Mirabegron

updated

Mirabegron is an FDA-approved beta-3 adrenergic agonist (MYRBETRIQ, 2012) for overactive bladder. It activates brown fat in small studies, but at doses above the labeled maximum, and a PubMed search on 9 October 2026 found no randomized trial with weight loss, fat mass or body composition as a primary endpoint.

Beta-3 adrenergic agonist

  • FDA approved MYRBETRIQ under NDA 202611 on 28 June 2012; the granules followed under NDA 213801 on 25 March 2021. The label has no obesity or fat-loss indication.
  • In 12 healthy men, a single dose at four times the labeled maximum raised resting metabolic rate by 203 +/- 40 kcal/day (13%).
  • In the study that compared doses, only the highest dose raised both nonesterified fatty acids (68%) and resting energy expenditure (5.8%).
  • In 14 healthy women, 4 weeks at twice the labeled maximum raised brown fat activity and resting energy expenditure but did not change body weight or body composition.
  • In the label's thorough QT study of 352 healthy subjects, maximum mean heart rate increases were 6.7, 11 and 17 bpm at the maximum recommended dose and at twice and four times that dose.
  • A PubMed search on 9 October 2026 for mirabegron with weight loss, body composition or fat mass returned 15 records; none was a randomized human trial with those as a primary endpoint.

What is mirabegron approved to do?

FDA approved mirabegron as MYRBETRIQ in 2012 for overactive bladder in adults and later for neurogenic detrusor overactivity in children. There is no labeled use for obesity, fat loss or body composition.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate, and for neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. FDA approved it under NDA 202611 on 28 June 2012, and MYRBETRIQ Granules under NDA 213801 on 25 March 2021. The label has no indication for obesity, fat loss, body composition or metabolic disease.

The approval program used three randomized 12-week placebo-controlled overactive-bladder trials with urinary endpoints, incontinence episodes and micturitions per 24 hours. Across the phase 2 and 3 program, 5648 patients received monotherapy, of whom 2029 (35.9%) were 65 or older.

Mirabegron is C21H24N4O2S (396.5 g/mol, CAS 223673-61-8). Listed synonyms include Myrbetriq, Betmiga and the development code YM-178. The Myrbetriq tablet is extended-release, so an immediate-release or compounded preparation of the same molecule is not pharmacokinetically interchangeable with it.

MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source
MYRBETRIQ label trials: three 12-week trials, urinary endpoints, 5648 patients on monotherapy

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) prescribing information, clinical studies section, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

Three randomized 12-week placebo-controlled overactive-bladder trials used co-primary endpoints of change from baseline at week 12 in mean incontinence episodes per 24 hours and mean micturitions per 24 hours from a 3-day diary, with mean volume voided per micturition as an important secondary endpoint. Study 3 is NCT00912964. The effect appeared within 4 weeks and was maintained through 12 weeks at both studied doses. Across the phase 2 and 3 overactive-bladder program, 5648 patients received MYRBETRIQ monotherapy, of whom 2029 (35.9%) were 65 or older.

Participants / model
Adults with overactive bladder
Treatment
Oral mirabegron at the two labeled doses, 12 weeks
Follow-up
12 weeks
Study design
Label summary of randomized placebo-controlled trials
Funding
not stated in the source

The endpoints in the approval program are urinary, not metabolic.

Read the original source
Drugs@FDA: MYRBETRIQ 2012, granules 2021

Regulatory record

U.S. Food and Drug Administration. Drugs@FDA application record for NDA 202611 (MYRBETRIQ), with NDA 213801 (MYRBETRIQ Granules). Dates read from the openFDA Drugs@FDA records.

FDA approved MYRBETRIQ under NDA 202611 on 28 June 2012, and MYRBETRIQ Granules under NDA 213801 on 25 March 2021.

Participants / model
Not a clinical population
Treatment
Drug applications
Follow-up
Approvals in 2012 and 2021
Study design
FDA application records
Funding
not stated in the source

These records give approval dates. Indications come from the product label.

Read the original source
PubChem: mirabegron identity

Chemical identity record

National Library of Medicine. PubChem compound record CID 9865528 (mirabegron).

Mirabegron: C21H24N4O2S, 396.5 g/mol, CAS 223673-61-8. Listed synonyms include Myrbetriq, Betmiga and the development code YM-178. The Myrbetriq tablet is an extended-release formulation, so an immediate-release or compounded preparation of the same molecule is not pharmacokinetically interchangeable with it.

Participants / model
Chemical identity, not a clinical population
Treatment
Defined molecule
Follow-up
Not applicable
Study design
NLM chemical record
Funding
not stated in the source

Identity record only; it says nothing about efficacy or safety. The extended-release point comes from the product label.

Read the original source

What did the brown-fat studies find in people?

Mirabegron activated brown fat and raised resting energy expenditure in small studies at doses above the labeled maximum. In 14 healthy women, 4 weeks at twice that dose changed neither body weight nor body composition.

The founding study gave 12 healthy men a single oral dose at four times the labeled maximum, or placebo. Brown adipose tissue metabolic activity on 18F-FDG PET/CT rose in all twelve (p=0.001), and resting metabolic rate rose by 203 +/- 40 kcal/day, a 13% increase (p=0.001). Brown fat activity significantly predicted the change in resting metabolic rate (p=0.006).

The longest dedicated metabolic study measured body composition. Fourteen healthy women (age 27.5 +/- 1.1 years, BMI 25.4 +/- 1.2) took extended-release mirabegron at twice the labeled maximum daily for 4 weeks in an open-label study. Brown adipose tissue activity and whole-body resting energy expenditure rose, with no changes in body weight or body composition. HDL, ApoA1 and total bile acids rose, adiponectin was 35% higher at study end, and an intravenous glucose tolerance test showed higher insulin sensitivity, glucose effectiveness and insulin secretion.

A meta-analysis pooled 6 of 10 reviewed papers on mirabegron and human brown adipose tissue. It found no significant change in brown adipose tissue volume (p=0.72) or blood glucose (p=0.52), and significant increases in brown adipose tissue activity, nonesterified fatty acids, body temperature, resting energy expenditure, heart rate, diastolic blood pressure and blood insulin (all p<0.01). Systolic blood pressure was not significant (p=0.25). Weight and fat mass were not among the pooled outcomes, because the underlying studies did not supply them.

Founding brown-fat study: 12 healthy men, one dose at four times the labeled maximum

Randomized controlled trial

Cypess AM et al. Cell Metab. 2015;21(1):33-8. PMID 25565203.

Mirabegron raised brown adipose tissue metabolic activity, measured by 18F-FDG PET/CT, in all twelve men (p=0.001) and raised resting metabolic rate by 203 +/- 40 kcal/day, a 13% increase (p=0.001). Brown fat activity significantly predicted the change in resting metabolic rate (p=0.006).

Participants / model
12 healthy men
Treatment
A single oral dose at four times the labeled maximum, or placebo
Follow-up
Single dose
Study design
Randomized placebo-controlled study
Funding
not stated in the source

The dose was four times the labeled maximum. The result is for a single dose in healthy men.

Read the original source
Four-week study: 14 healthy women, twice the labeled maximum, no change in weight or composition

Clinical trial

O'Mara AE et al. J Clin Invest. 2020;130(5):2209-2219. PMID 31961826.

Brown adipose tissue metabolic activity increased and whole-body resting energy expenditure was higher, with no changes in body weight or body composition. HDL, ApoA1 and total bile acids rose, and adiponectin was 35% higher at study end. An intravenous glucose tolerance test showed higher insulin sensitivity, glucose effectiveness and insulin secretion.

Participants / model
14 healthy women of diverse ethnicities (age 27.5 +/- 1.1 years, BMI 25.4 +/- 1.2)
Treatment
Oral extended-release mirabegron at twice the labeled maximum daily, open label
Follow-up
4 weeks
Study design
Open-label study; registered as NCT03049462
Funding
not stated in the source

Twice the labeled dose for a month moved the mechanism and did not move body weight or composition.

Read the original source
Meta-analysis: 6 pooled human studies, no change in brown fat volume

Systematic review and meta-analysis

Ma L et al. Eur J Clin Pharmacol. 2024;80(3):317-333. PMID 38159219.

Pooling 6 of 10 reviewed papers, mirabegron produced no significant change in brown adipose tissue volume (p=0.72) or blood glucose (p=0.52). It significantly increased brown adipose tissue activity (p<0.01), nonesterified fatty acids (p<0.01), body temperature (p<0.01), resting energy expenditure (p<0.01), heart rate (p<0.01), diastolic blood pressure (p<0.01) and blood insulin (p<0.01). Systolic blood pressure was not significant (p=0.25), although the abstract's conclusion lists blood pressure generally among the increases; this page follows the reported p value. Weight and fat mass are not among the pooled outcomes, because the underlying studies did not supply them.

Participants / model
Participants across 6 pooled human studies
Treatment
Oral mirabegron at the doses used in the included studies
Follow-up
Varied by included study
Study design
Systematic review and meta-analysis; PROSPERO CRD42023413446
Funding
not stated in the source

Weight and fat mass were not pooled.

Read the original source

Do the studied doses match the labeled dose?

No. The brown-fat studies used doses above the labeled maximum. In the one study that compared doses, only the highest dose raised both nonesterified fatty acids and resting energy expenditure.

The founding brown-fat study used four times the labeled maximum dose. The study that separates the labeled dose from the studied dose gave 12 healthy men one-time randomized doses of placebo, the approved maximum dose and four times that dose. Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL.

Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The labeled maximum dose did not. The lipolysis and energy-expenditure endpoints that the supplier claim depends on were therefore not both raised at the labeled dose.

The label's own dose-response data show that the higher doses also raise heart rate and blood pressure more: maximum mean heart rate increases versus placebo were 6.7, 11 and 17 bpm at the maximum recommended dose, twice that dose and four times that dose. No supratherapeutic dose is given on this page as a usable number.

Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source
Founding brown-fat study: 12 healthy men, one dose at four times the labeled maximum

Randomized controlled trial

Cypess AM et al. Cell Metab. 2015;21(1):33-8. PMID 25565203.

Mirabegron raised brown adipose tissue metabolic activity, measured by 18F-FDG PET/CT, in all twelve men (p=0.001) and raised resting metabolic rate by 203 +/- 40 kcal/day, a 13% increase (p=0.001). Brown fat activity significantly predicted the change in resting metabolic rate (p=0.006).

Participants / model
12 healthy men
Treatment
A single oral dose at four times the labeled maximum, or placebo
Follow-up
Single dose
Study design
Randomized placebo-controlled study
Funding
not stated in the source

The dose was four times the labeled maximum. The result is for a single dose in healthy men.

Read the original source
MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source

What happened in obese, insulin-resistant adults?

In obese, insulin-resistant adults, glucose tolerance, HbA1c and insulin sensitivity improved. The abstract reports no body weight or fat mass result, so it does not support a recomposition claim.

This is the study in the population the supplier claim targets. In obese, insulin-resistant people treated with mirabegron, oral glucose tolerance improved (P<0.01), HbA1c fell (P=0.01), insulin sensitivity improved (P=0.03) and beta cell function improved (P=0.01). In subcutaneous white adipose tissue, mirabegron stimulated lipolysis, reduced fibrotic gene expression and increased alternatively activated macrophages. In skeletal muscle it reduced triglycerides, raised PGC1A expression (P<0.05) and increased type I fibers (P<0.01).

The published abstract reports no body weight or fat mass result, and it states no dose or treatment duration, so none is attributed here. The registry record NCT02919176 is an early phase 1 study listing 39 participants and no posted results.

Obese, insulin-resistant adults: glucose and tissue changes; no weight or fat result reported

Clinical trial

Finlin BS et al. J Clin Invest. 2020;130(5):2319-2331. PMID 31961829.

In obese, insulin-resistant people treated with mirabegron, oral glucose tolerance improved (P<0.01), HbA1c fell (P=0.01), insulin sensitivity improved (P=0.03) and beta cell function improved (P=0.01). In subcutaneous white adipose tissue, mirabegron stimulated lipolysis, reduced fibrotic gene expression and increased alternatively activated macrophages. In skeletal muscle it reduced triglycerides, raised PGC1A expression (P<0.05) and increased type I fibers (P<0.01). The published abstract reports no body weight or fat mass result and states no dose or treatment duration.

Participants / model
Obese, insulin-resistant adults; the registry record NCT02919176 lists 39 participants
Treatment
Oral mirabegron; dose and duration not stated in the abstract
Follow-up
not stated in the source
Study design
Clinical trial; the registry record is an early phase 1 study with no posted results
Funding
not stated in the source

The glucose and tissue findings are reported; a recomposition claim is not supported by what the abstract reports. No dose or duration is attributed to this study.

Read the original source

Does mirabegron cause fat loss or recomposition?

No trial has tested it. A PubMed search on 9 October 2026 for mirabegron with weight loss, body composition or fat mass returned 15 records, and none was a randomized human trial with those as a primary endpoint.

Sellers promote mirabegron for fat loss and recomposition through thermogenesis and lipolysis, by activating brown adipose tissue and browning white adipose tissue. The brown-fat activation is real in the studies above, but it appeared at doses above the labeled maximum, and 4 weeks at twice that dose changed neither body weight nor composition.

The 15 PubMed records were reviews, mouse and microneedle-patch studies, two overactive-bladder systematic reviews, and the human brown-fat work already cited. On ClinicalTrials.gov the same day, a query for mirabegron and obesity returned 11 studies and a query for mirabegron and brown adipose tissue returned 12, all mechanism, thermogenesis or glucose-tolerance studies. The largest mirabegron entry was NCT05051436 (phase 4, n=96, recruiting, glucose tolerance in prediabetics), with the rest between 9 and 60 participants. None named weight loss or body composition as its stated subject.

PubMed search, 9 October 2026: 15 records, no randomized weight-loss trial

PubMed search record

PubMed search run on 9 October 2026: mirabegron AND (weight loss OR body composition OR fat mass). 15 records returned. ClinicalTrials.gov queries the same day for mirabegron with obesity (11 studies) and with brown adipose tissue (12 studies).

The PubMed search returned 15 records: reviews, mouse and microneedle-patch studies, two overactive-bladder systematic reviews, and the human brown-fat work already cited. None was a randomized human trial with weight loss, fat mass or body composition as a primary endpoint. On ClinicalTrials.gov the same day, a query for mirabegron and obesity returned 11 studies and a query for mirabegron and brown adipose tissue returned 12, all mechanism, thermogenesis or glucose-tolerance studies. The largest mirabegron entry was NCT05051436 (phase 4, n=96, recruiting, glucose tolerance in prediabetics), with the rest between 9 and 60 participants, and none naming weight loss or body composition as its stated subject. In the records reviewed, no trial has tested mirabegron for weight loss or recomposition as a primary endpoint.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 9 October 2026
Study design
Literature and registry search
Funding
not stated in the source

A search result shows what the databases returned on that date. It is not proof that no unindexed study exists.

Read the original source
Four-week study: 14 healthy women, twice the labeled maximum, no change in weight or composition

Clinical trial

O'Mara AE et al. J Clin Invest. 2020;130(5):2209-2219. PMID 31961826.

Brown adipose tissue metabolic activity increased and whole-body resting energy expenditure was higher, with no changes in body weight or body composition. HDL, ApoA1 and total bile acids rose, and adiponectin was 35% higher at study end. An intravenous glucose tolerance test showed higher insulin sensitivity, glucose effectiveness and insulin secretion.

Participants / model
14 healthy women of diverse ethnicities (age 27.5 +/- 1.1 years, BMI 25.4 +/- 1.2)
Treatment
Oral extended-release mirabegron at twice the labeled maximum daily, open label
Follow-up
4 weeks
Study design
Open-label study; registered as NCT03049462
Funding
not stated in the source

Twice the labeled dose for a month moved the mechanism and did not move body weight or composition.

Read the original source
Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source

How does mirabegron work?

Mirabegron is a beta-3 adrenergic agonist. Single doses above the labeled maximum activated brown fat in healthy men, and the approval program measured urinary endpoints, not metabolic ones.

Mirabegron is a beta-3 adrenergic agonist, the mechanism behind its bladder indication. In healthy men, single doses above the labeled maximum raised brown adipose tissue metabolic activity on 18F-FDG PET/CT, and the highest dose raised nonesterified fatty acids and resting energy expenditure.

Human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue. The same single-dose study reported a 35% increase in gallbladder size and reductions in conjugated bile acids, with no chronic-use follow-up. The approval program's endpoints were urinary, not metabolic, and the approved product is an extended-release tablet.

MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source
MYRBETRIQ label trials: three 12-week trials, urinary endpoints, 5648 patients on monotherapy

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) prescribing information, clinical studies section, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

Three randomized 12-week placebo-controlled overactive-bladder trials used co-primary endpoints of change from baseline at week 12 in mean incontinence episodes per 24 hours and mean micturitions per 24 hours from a 3-day diary, with mean volume voided per micturition as an important secondary endpoint. Study 3 is NCT00912964. The effect appeared within 4 weeks and was maintained through 12 weeks at both studied doses. Across the phase 2 and 3 overactive-bladder program, 5648 patients received MYRBETRIQ monotherapy, of whom 2029 (35.9%) were 65 or older.

Participants / model
Adults with overactive bladder
Treatment
Oral mirabegron at the two labeled doses, 12 weeks
Follow-up
12 weeks
Study design
Label summary of randomized placebo-controlled trials
Funding
not stated in the source

The endpoints in the approval program are urinary, not metabolic.

Read the original source
Founding brown-fat study: 12 healthy men, one dose at four times the labeled maximum

Randomized controlled trial

Cypess AM et al. Cell Metab. 2015;21(1):33-8. PMID 25565203.

Mirabegron raised brown adipose tissue metabolic activity, measured by 18F-FDG PET/CT, in all twelve men (p=0.001) and raised resting metabolic rate by 203 +/- 40 kcal/day, a 13% increase (p=0.001). Brown fat activity significantly predicted the change in resting metabolic rate (p=0.006).

Participants / model
12 healthy men
Treatment
A single oral dose at four times the labeled maximum, or placebo
Follow-up
Single dose
Study design
Randomized placebo-controlled study
Funding
not stated in the source

The dose was four times the labeled maximum. The result is for a single dose in healthy men.

Read the original source
Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source

What warnings and side effects does the label report?

The label warns that mirabegron can increase blood pressure and is not recommended in severe uncontrolled hypertension. Heart rate and blood pressure effects are dose-dependent, and the label also warns about urinary retention and angioedema.

In the label's thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean heart rate increases versus placebo were 6.7, 11 and 17 bpm. Twenty-four-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo.

The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In overactive-bladder trials at the maximum recommended dose, mean pulse rate rose approximately 1 bpm and blood pressure approximately 0.5 to 1 mm Hg over placebo.

In overdose studies in healthy volunteers, single doses at several times the maximum recommended dose produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses for 10 days raised pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx. The 35% gallbladder enlargement came from single doses in 12 men and has no chronic-use follow-up.

MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source
Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source

Why does mirabegron sit in A tier?

An FDA approval, a large overactive-bladder program and a real brown-fat mechanism support the A for the compound. The fat-loss claim fails on dose and outcome.

Mirabegron has been FDA-approved since 2012, and 5648 patients received monotherapy in the overactive-bladder program, so the compound is well evidenced for a narrow urinary label. The A reflects that it is now promoted far outside that label.

The supplier claim fails on dose and on outcome. The brown-fat effects needed doses above the labeled maximum, only the highest dose raised both nonesterified fatty acids and resting energy expenditure, 4 weeks at twice the labeled maximum changed neither body weight nor composition, and the doses that move metabolism also raise heart rate and blood pressure. No trial found has tested weight loss or recomposition as a primary endpoint.

MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source
MYRBETRIQ label trials: three 12-week trials, urinary endpoints, 5648 patients on monotherapy

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) prescribing information, clinical studies section, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

Three randomized 12-week placebo-controlled overactive-bladder trials used co-primary endpoints of change from baseline at week 12 in mean incontinence episodes per 24 hours and mean micturitions per 24 hours from a 3-day diary, with mean volume voided per micturition as an important secondary endpoint. Study 3 is NCT00912964. The effect appeared within 4 weeks and was maintained through 12 weeks at both studied doses. Across the phase 2 and 3 overactive-bladder program, 5648 patients received MYRBETRIQ monotherapy, of whom 2029 (35.9%) were 65 or older.

Participants / model
Adults with overactive bladder
Treatment
Oral mirabegron at the two labeled doses, 12 weeks
Follow-up
12 weeks
Study design
Label summary of randomized placebo-controlled trials
Funding
not stated in the source

The endpoints in the approval program are urinary, not metabolic.

Read the original source
Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source
Four-week study: 14 healthy women, twice the labeled maximum, no change in weight or composition

Clinical trial

O'Mara AE et al. J Clin Invest. 2020;130(5):2209-2219. PMID 31961826.

Brown adipose tissue metabolic activity increased and whole-body resting energy expenditure was higher, with no changes in body weight or body composition. HDL, ApoA1 and total bile acids rose, and adiponectin was 35% higher at study end. An intravenous glucose tolerance test showed higher insulin sensitivity, glucose effectiveness and insulin secretion.

Participants / model
14 healthy women of diverse ethnicities (age 27.5 +/- 1.1 years, BMI 25.4 +/- 1.2)
Treatment
Oral extended-release mirabegron at twice the labeled maximum daily, open label
Follow-up
4 weeks
Study design
Open-label study; registered as NCT03049462
Funding
not stated in the source

Twice the labeled dose for a month moved the mechanism and did not move body weight or composition.

Read the original source
PubMed search, 9 October 2026: 15 records, no randomized weight-loss trial

PubMed search record

PubMed search run on 9 October 2026: mirabegron AND (weight loss OR body composition OR fat mass). 15 records returned. ClinicalTrials.gov queries the same day for mirabegron with obesity (11 studies) and with brown adipose tissue (12 studies).

The PubMed search returned 15 records: reviews, mouse and microneedle-patch studies, two overactive-bladder systematic reviews, and the human brown-fat work already cited. None was a randomized human trial with weight loss, fat mass or body composition as a primary endpoint. On ClinicalTrials.gov the same day, a query for mirabegron and obesity returned 11 studies and a query for mirabegron and brown adipose tissue returned 12, all mechanism, thermogenesis or glucose-tolerance studies. The largest mirabegron entry was NCT05051436 (phase 4, n=96, recruiting, glucose tolerance in prediabetics), with the rest between 9 and 60 participants, and none naming weight loss or body composition as its stated subject. In the records reviewed, no trial has tested mirabegron for weight loss or recomposition as a primary endpoint.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 9 October 2026
Study design
Literature and registry search
Funding
not stated in the source

A search result shows what the databases returned on that date. It is not proof that no unindexed study exists.

Read the original source

Studies and sources

PubChem: mirabegron identity

Chemical identity record

National Library of Medicine. PubChem compound record CID 9865528 (mirabegron).

Mirabegron: C21H24N4O2S, 396.5 g/mol, CAS 223673-61-8. Listed synonyms include Myrbetriq, Betmiga and the development code YM-178. The Myrbetriq tablet is an extended-release formulation, so an immediate-release or compounded preparation of the same molecule is not pharmacokinetically interchangeable with it.

Participants / model
Chemical identity, not a clinical population
Treatment
Defined molecule
Follow-up
Not applicable
Study design
NLM chemical record
Funding
not stated in the source

Identity record only; it says nothing about efficacy or safety. The extended-release point comes from the product label.

Read the original source
MYRBETRIQ label, version effective 1 August 2024: indications, cardiovascular effects, overdose, warnings

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) extended-release oral tablets and extended-release oral suspension granules, prescribing information, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

MYRBETRIQ is a beta-3 adrenergic agonist labeled for two uses: overactive bladder in adults with urge urinary incontinence, urgency and urinary frequency, alone or with solifenacin succinate; and neurogenic detrusor overactivity in children aged 3 and older weighing 35 kg or more. There is no labeled indication for obesity, fat loss, body composition or metabolic disease. In a thorough QT study of 352 healthy subjects given the maximum recommended dose, twice that dose or four times that dose daily for 10 days, maximum mean increases in heart rate versus placebo were 6.7, 11 and 17 bpm, and 24-hour average systolic blood pressure increases versus placebo were 3.0, 5.5 and 9.7 mm Hg. At the maximum recommended dose, the maximum mean increase in supine systolic over diastolic pressure was approximately 4.0/1.6 mm Hg over placebo. The label warns that the drug can increase blood pressure, requires periodic monitoring especially in hypertensive patients, and is not recommended in severe uncontrolled hypertension (systolic at or above 180 or diastolic at or above 110 mm Hg). In adult overactive-bladder trials at the maximum recommended dose, the mean pulse-rate change from baseline was approximately 1 bpm and the mean blood pressure increase approximately 0.5 to 1 mm Hg over placebo. In the overdose section, single doses at several times the maximum recommended dose in healthy volunteers produced palpitations in 1 of 6 subjects and a pulse rate above 100 bpm in 3 of 6, and multiple daily doses at several times the maximum for 10 days increased pulse rate and systolic blood pressure. The label recommends pulse rate, blood pressure and ECG monitoring in overdose. Other warnings are urinary retention in patients with bladder outlet obstruction or taking muscarinic antagonists, and angioedema of the face, lips, tongue or larynx.

Participants / model
Adults with overactive bladder; children 3 and older with neurogenic detrusor overactivity; 352 healthy subjects in the thorough QT study; healthy volunteers in the overdose studies
Treatment
MYRBETRIQ extended-release oral tablets and extended-release oral suspension granules
Follow-up
Label version effective 1 August 2024
Study design
FDA prescribing information
Funding
not stated in the source

The cardiovascular effects are dose-dependent, which matters for any use at doses above the label. No supratherapeutic dose is given here as a usable number.

Read the original source
MYRBETRIQ label trials: three 12-week trials, urinary endpoints, 5648 patients on monotherapy

FDA prescribing information

DailyMed, U.S. National Library of Medicine. MYRBETRIQ (mirabegron) prescribing information, clinical studies section, label version effective 1 August 2024. Set ID ba9e9e15-e666-4c56-9271-2e24739cfa2d.

Three randomized 12-week placebo-controlled overactive-bladder trials used co-primary endpoints of change from baseline at week 12 in mean incontinence episodes per 24 hours and mean micturitions per 24 hours from a 3-day diary, with mean volume voided per micturition as an important secondary endpoint. Study 3 is NCT00912964. The effect appeared within 4 weeks and was maintained through 12 weeks at both studied doses. Across the phase 2 and 3 overactive-bladder program, 5648 patients received MYRBETRIQ monotherapy, of whom 2029 (35.9%) were 65 or older.

Participants / model
Adults with overactive bladder
Treatment
Oral mirabegron at the two labeled doses, 12 weeks
Follow-up
12 weeks
Study design
Label summary of randomized placebo-controlled trials
Funding
not stated in the source

The endpoints in the approval program are urinary, not metabolic.

Read the original source
Drugs@FDA: MYRBETRIQ 2012, granules 2021

Regulatory record

U.S. Food and Drug Administration. Drugs@FDA application record for NDA 202611 (MYRBETRIQ), with NDA 213801 (MYRBETRIQ Granules). Dates read from the openFDA Drugs@FDA records.

FDA approved MYRBETRIQ under NDA 202611 on 28 June 2012, and MYRBETRIQ Granules under NDA 213801 on 25 March 2021.

Participants / model
Not a clinical population
Treatment
Drug applications
Follow-up
Approvals in 2012 and 2021
Study design
FDA application records
Funding
not stated in the source

These records give approval dates. Indications come from the product label.

Read the original source
Founding brown-fat study: 12 healthy men, one dose at four times the labeled maximum

Randomized controlled trial

Cypess AM et al. Cell Metab. 2015;21(1):33-8. PMID 25565203.

Mirabegron raised brown adipose tissue metabolic activity, measured by 18F-FDG PET/CT, in all twelve men (p=0.001) and raised resting metabolic rate by 203 +/- 40 kcal/day, a 13% increase (p=0.001). Brown fat activity significantly predicted the change in resting metabolic rate (p=0.006).

Participants / model
12 healthy men
Treatment
A single oral dose at four times the labeled maximum, or placebo
Follow-up
Single dose
Study design
Randomized placebo-controlled study
Funding
not stated in the source

The dose was four times the labeled maximum. The result is for a single dose in healthy men.

Read the original source
Dose comparison: 12 healthy men, placebo, labeled maximum and four times that

Randomized controlled trial

Baskin AS et al. Diabetes. 2018;67(10):2113-2125. PMID 29980535.

Brown adipose tissue metabolic activity rose more than dose-proportionally: medians 0.0 versus 18.2 versus 305.6 mL x SUVmean x g/mL for placebo, the labeled maximum and four times that dose. Only the highest dose elevated both nonesterified fatty acids (68%) and resting energy expenditure (5.8%). The study also reported a previously undescribed 35% increase in gallbladder size and reductions in conjugated bile acids, and showed that human beta-3 adrenergic receptor mRNA is highly expressed in gallbladder as well as brown adipose tissue.

Participants / model
12 healthy men
Treatment
Single oral doses of placebo, the approved maximum dose, and four times that dose, in random order
Follow-up
Single doses
Study design
Randomized crossover study
Funding
not stated in the source

The gallbladder finding comes from single doses in 12 men and has no chronic-use follow-up.

Read the original source
Four-week study: 14 healthy women, twice the labeled maximum, no change in weight or composition

Clinical trial

O'Mara AE et al. J Clin Invest. 2020;130(5):2209-2219. PMID 31961826.

Brown adipose tissue metabolic activity increased and whole-body resting energy expenditure was higher, with no changes in body weight or body composition. HDL, ApoA1 and total bile acids rose, and adiponectin was 35% higher at study end. An intravenous glucose tolerance test showed higher insulin sensitivity, glucose effectiveness and insulin secretion.

Participants / model
14 healthy women of diverse ethnicities (age 27.5 +/- 1.1 years, BMI 25.4 +/- 1.2)
Treatment
Oral extended-release mirabegron at twice the labeled maximum daily, open label
Follow-up
4 weeks
Study design
Open-label study; registered as NCT03049462
Funding
not stated in the source

Twice the labeled dose for a month moved the mechanism and did not move body weight or composition.

Read the original source
Obese, insulin-resistant adults: glucose and tissue changes; no weight or fat result reported

Clinical trial

Finlin BS et al. J Clin Invest. 2020;130(5):2319-2331. PMID 31961829.

In obese, insulin-resistant people treated with mirabegron, oral glucose tolerance improved (P<0.01), HbA1c fell (P=0.01), insulin sensitivity improved (P=0.03) and beta cell function improved (P=0.01). In subcutaneous white adipose tissue, mirabegron stimulated lipolysis, reduced fibrotic gene expression and increased alternatively activated macrophages. In skeletal muscle it reduced triglycerides, raised PGC1A expression (P<0.05) and increased type I fibers (P<0.01). The published abstract reports no body weight or fat mass result and states no dose or treatment duration.

Participants / model
Obese, insulin-resistant adults; the registry record NCT02919176 lists 39 participants
Treatment
Oral mirabegron; dose and duration not stated in the abstract
Follow-up
not stated in the source
Study design
Clinical trial; the registry record is an early phase 1 study with no posted results
Funding
not stated in the source

The glucose and tissue findings are reported; a recomposition claim is not supported by what the abstract reports. No dose or duration is attributed to this study.

Read the original source
Meta-analysis: 6 pooled human studies, no change in brown fat volume

Systematic review and meta-analysis

Ma L et al. Eur J Clin Pharmacol. 2024;80(3):317-333. PMID 38159219.

Pooling 6 of 10 reviewed papers, mirabegron produced no significant change in brown adipose tissue volume (p=0.72) or blood glucose (p=0.52). It significantly increased brown adipose tissue activity (p<0.01), nonesterified fatty acids (p<0.01), body temperature (p<0.01), resting energy expenditure (p<0.01), heart rate (p<0.01), diastolic blood pressure (p<0.01) and blood insulin (p<0.01). Systolic blood pressure was not significant (p=0.25), although the abstract's conclusion lists blood pressure generally among the increases; this page follows the reported p value. Weight and fat mass are not among the pooled outcomes, because the underlying studies did not supply them.

Participants / model
Participants across 6 pooled human studies
Treatment
Oral mirabegron at the doses used in the included studies
Follow-up
Varied by included study
Study design
Systematic review and meta-analysis; PROSPERO CRD42023413446
Funding
not stated in the source

Weight and fat mass were not pooled.

Read the original source

Why is Mirabegron in A tier?

A fits an approved drug well evidenced for a narrow label and promoted far outside it. The brown-fat mechanism is real, but it appeared at doses above the labeled maximum, and nothing found tests weight loss or body composition as a primary endpoint.