Methenolone

a non-17-alpha-alkylated androgen with a current Japanese oral acetate label, historical injectable enanthate use, and no validated systemic half-life for either formulation.

tier B · androgens · 0 validated systemic half-life studies located

verdict

Japan's current oral acetate label supplies a real foreign medical record, while the missing human PK and modern organ-safety file keep the evidence below top tier.

if you are asking whether oral Primobolan is 17-alpha-alkylated — no. methenolone acetate is orally active without a 17-alpha alkyl group. it should not inherit the signature cholestasis classification of oxandrolone, stanozolol, methandienone, or oxymetholone.

if you are asking whether acetate and enanthate share a half-life — no. no qualifying systemic half-life was located for either, and a vendor's roughly 10-day enanthate value is not accepted.

if you are asking whether it is approved anywhere — yes. Japan's PMDA lists Primobolan 5 mg oral methenolone acetate tablets. no current US product was located.

Urine or feces detection after oral acetate and calf metabolism work does not become a plasma elimination half-life.

why B-tier

B tier reflects a clear molecule and current foreign label with a strong older medical record. The absence of systemic PK, modern controlled outcomes, and contemporary organ-safety data remains material.

the core tension

Methenolone has a real current foreign label and a chemically distinct oral design, but no validated systemic half-life or modern controlled cardiovascular and body-composition dataset closes the major gaps.

what it is

Methenolone is a 1-methyl, 5-alpha-androst-1-ene androgen. Oral Primobolan uses the acetate ester. Historical depot products used methenolone enanthate in oil. The esters and routes are separate products.

what it does

After ester hydrolysis, methenolone activates the androgen receptor. Its 5-alpha-reduced A-ring is not an aromatase substrate. Oral activity comes from the 1-methyl and double-bonded structure rather than a 17-alpha alkyl group.

origin

Japan's Primobolan 5 mg oral tablet has a current PMDA label with a 1962 marketing history. The label describes osteoporosis, wasting, and marrow-depletion indications and includes virilization, hepatic, edema, glucose, interaction, and pediatric growth warnings.

why researchers are interested

Its non-aromatizing and non-17-alpha-alkylated structure drives a low-risk reputation. The absence of one structural liability does not supply controlled cardiovascular, reproductive, or long-term safety data.

does it work

The current Japanese label establishes a medical and regulatory record, but the located English-accessible evidence does not provide a modern pivotal body-composition outcome or a systemic half-life. That is a strong older and foreign B-tier file.

claims vs the data

• all oral anabolic steroids are 17-alpha-alkylated — contradicted — methenolone acetate is the cohort's important exception.
• methenolone enanthate has a verified 10.5-day human half-life — unsupported — no qualifying primary systemic PK study was located.
• the oral acetate label validates depot enanthate — contradicted — the formulations, routes, and PK are distinct.

key facts

• molecular formula: C22H32O3 (acetate); C27H42O3 (enanthate)
• molecular weight: 344.49 g/mol (acetate); 414.63 g/mol (enanthate)
• amino acids: n/a (steroidal small molecule, not a peptide)
• half-life: unknown; no qualifying systemic plasma half-life located for acetate or enanthate
• type: 1-methyl, 5-alpha-androst-1-ene anabolic-androgenic steroid; oral acetate and injectable enanthate are distinct formulations
• CAS: 434-05-9 (acetate); 303-42-4 (enanthate)
• 1962 Japanese oral product marketing history
• 2 formulations kept separate
• 0 validated systemic half-life studies located
• 4 wk rat cardiac-remodeling exposure

frequently asked questions

Is methenolone FDA-approved?

No current US approval was located. Japan's PMDA lists a current oral methenolone acetate product, so the page classifies it as approved abroad.

Is oral methenolone acetate 17-alpha-alkylated?

No. Its oral activity does not come from the 17-alpha alkyl group carried by four other oral androgens in this cohort.

What is Primobolan Depot's half-life?

No qualifying systemic human or animal half-life for methenolone enanthate was located. Vendor and community estimates are not published as verified PK.

Does non-aromatizing mean low risk?

No. Androgen-receptor effects, gonadal suppression, virilization, erythrocytosis, edema, lipid and cardiovascular effects, and product-quality risk remain relevant.

related peptides

• Drostanolone — another 5-alpha-reduced non-aromatizing androgen with an older medical record
• Oxandrolone — an oral DHT-derived comparator that is 17-alpha-alkylated
• Nandrolone — an injectable ester with actual human depot PK

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.