Nandrolone

Lean tissue

Human trials show gains in fat-free mass. Strength and physical function improve less consistently.^{1128,1129,1130}

Deca and NPP

Decanoate and phenylpropionate release the same parent steroid at different rates. The half-life and hormone-suppression results depend on formulation.^1131,1132

The joint-pain evidence

The joint-pain pilot had follow-up from 18 of 48 men, all receiving testosterone alongside nandrolone. Thirteen reported pain improvement. Structural healing was not measured.¹¹³³

About this chapter

Selected studies through October 1, 2026 leave long-term safety and several regional records unresolved.

Common questions

01 Are Deca and NPP the same drug?

They release the same parent drug, nandrolone, from different esters. Deca usually means decanoate; NPP means phenylpropionate. The ester changes how the injection releases the drug.^{1131,1135,1136}

02 Is nandrolone a peptide?

It is an anabolic-androgenic steroid, a small molecule related to testosterone. Decanoate and phenylpropionate are ester forms of that steroid.^{1137,1135,1136}

03 How much lean mass did the bodybuilder study find?

The eight-week study included 16 experienced male bodybuilders. In the nandrolone group, body mass rose 2.2 kg, fat-free mass 2.6 kg and total body water 1.4 kg. Fat mass did not change significantly.¹¹²⁸

04 Was that 2.6 kg all new muscle?

Fat-free mass includes water and other tissues. The study measured body compartments rather than isolated muscle protein, and total body water rose alongside fat-free mass.¹¹²⁸

05 Does it help with fat loss?

The bodybuilder trial found no significant fat loss. In a separate trial of postmenopausal women restricting calories, nandrolone increased lean mass but also increased visceral fat. Body weight alone can hide those differences.^1128,1138

06 Does more lean mass mean more strength?

The results vary. A dialysis study found better walking and stair performance but unchanged grip strength. In another dialysis trial, resistance exercise contributed to strength and function while nandrolone increased lean mass.^1129,1130

07 Has it been tested in people with HIV-related weight loss?

Yes. A 303-man trial found a 1.34 kg greater gain in fat-free mass than placebo over 12 weeks.¹¹³⁹

08 Did it work as well as growth hormone?

A smaller HIV trial reported lean-mass gains of 1.6 kg with nandrolone, 2.5 kg with growth hormone and 0.4 kg with placebo. It did not establish equivalence between the drugs, and the growth-hormone arm was open label.¹¹⁴⁰

09 Did it help people with COPD?

Findings were mixed. During pulmonary rehabilitation, one trial found more fat-free mass but similar overall functional improvements between groups. A separate small trial without structured rehabilitation found no benefit.^1141,1142

10 Can it speed recovery after intensive care?

A 22-person pilot did not show consistent improvement in its main strength and function outcomes. The groups started with different levels of weakness, which makes its shorter-hospital-stay finding difficult to attribute to nandrolone.¹¹⁴³

11 What did the joint-pain study actually show?

Of 48 men assessed at the start, only 18 supplied follow-up information. Thirteen of those 18 reported marked pain improvement. They were also receiving testosterone, and there was no control group.¹¹³³

12 Does less pain mean my cartilage or tendon has healed?

The pilot measured pain questionnaires; cartilage and tendon healing were outside its outcomes. A repair claim would need structural and functional outcomes that this study did not collect.¹¹³³

13 Has it been studied for weak bones?

Yes. In a two-year trial of 65 women over 70 with osteoporosis, new vertebral fractures were reported in 21% receiving nandrolone and 43% receiving placebo. That trial studied bone disease rather than sports-related joint pain.¹¹⁴⁴

14 Have women taken it in clinical studies?

Yes, including studies of osteoporosis and HIV-related weight loss. In an osteoporosis study, two women withdrew with excess hair growth or hoarseness. The historical label warns that some virilizing changes can be irreversible.^{1145,1146,1134}

15 Which changes need prompt medical attention?

New swelling, yellow skin or eyes, unusual bleeding, voice changes or other virilizing effects should be assessed promptly. The label identifies fluid retention, liver problems, bleeding interactions and potentially irreversible androgenic changes.¹¹³⁴

16 Can it suppress my own testosterone?

Yes. A 23-man study measured testosterone and inhibin after a single injection. The degree and timing of suppression differed with ester, injection site and oil volume.¹¹³¹

17 Can it affect erections or sperm production?

Impotence, reduced sperm production, testicular atrophy and changes in libido appear in the historical label. The size and timing of these risks vary with exposure and the person; the label does not give a reliable percentage for performance use.¹¹³⁴

18 Will changing to NPP prevent hormone suppression?

Both esters suppressed testosterone in the comparative study. Phenylpropionate produced an earlier, shorter suppression pattern than decanoate under the tested conditions.¹¹³¹

19 What is the measured half-life of Deca?

A single-dose study in 54 healthy men reported terminal half-lives of seven to 12 days for nandrolone decanoate. The estimate belongs to that formulation and study; it is not an NPP half-life.¹¹³²

20 Why do half-life estimates differ between products?

Release depends on the preparation. The direct comparison found effects from ester, injection site and oil volume. A published concentration curve must be read with those details.¹¹³¹

21 Why can a urine test stay positive after blood levels fall?

Urine tests measure metabolites as well as the original exposure. In the decanoate study, some urinary metabolites were detectable months later. That result covers detection; duration of benefit and hormone recovery require separate measurements.¹¹³²

22 Does injecting it avoid liver effects?

Injection does not eliminate liver risk. In a small two-year telomeropathy trial, liver-test elevations were common, although no treatment was stopped for liver toxicity. The historical label also includes serious liver warnings.^1147,1134

23 Does a normal cholesterol result make it heart-safe?

A cholesterol measurement answers only part of that question. The short nandrolone lipid study was small and did not measure heart attacks or other cardiovascular outcomes. Its separate mixed-steroid cohort had a different exposure.¹¹⁴⁸

24 Can it cause water retention?

Fluid retention and edema are recognized in the label. The label treats heart, kidney or liver disease as relevant to that risk. Changes on the scale may include water.^1134,1128

25 Can it interact with other medicines?

Product information flags stronger anticoagulant effects, lower diabetes-treatment requirements and increased fluid retention with corticosteroids. The Japanese warfarin label also specifically names nandrolone decanoate.^1163,1160

26 Is it suitable during pregnancy?

Pregnancy and breastfeeding are contraindications in the Australian prescribing information. Androgen exposure can affect fetal development, and the label warns of possible virilizing effects in a breastfed infant.¹¹⁶³

27 What are the concerns in children?

Androgens can accelerate bone maturation and affect growth. The telomeropathy trial also reported progressive signs of early puberty in a four-year-old child. Pediatric findings need specialist, disease-specific interpretation.^1134,1147

28 Does the telomere study show an anti-aging benefit?

The study enrolled 17 people with rare telomere disorders, and ten completed two years. It measured blood-cell telomeres and disease-related outcomes without a control group. Healthy aging and lifespan were not tested.¹¹⁴⁷

29 What happened to US Deca-Durabolin approval?

FDA withdrew the listed approval at the applicant's request, effective December 19, 2024. The notice says the products were no longer marketed. It does not identify a nandrolone safety finding as the reason.¹¹⁴⁹

30 Is it still registered in Australia?

TGA lists separate syringe and ampoule registrations with active status. Both pages also record zero declared turnover in 2024-25. The register establishes product status; current pharmacy supply needs its own check.^1150,1151

31 Is it banned in tested sport?

WADA lists nandrolone under anabolic-androgenic steroids, prohibited both in and out of competition. The published 2027 list retains that classification.^1152,1153

32 Is there human research on NPP as well as Deca?

Yes. Besides the ester-comparison study, a Chinese journal abstract describes 36 severely burned patients studied for albumin-related outcomes over 14 days. The full burn paper and its detailed methods still need review.^1131,1154

33 Have controlled studies tested knee pain?

An older trial studied 43 military patients with painful knees. A Cochrane review describes symptom improvement with NPP plus exercise, but rates the trial as low quality. Pain was not reported separately from the overall clinical assessment.¹¹⁵⁵

34 What happened after knee-replacement surgery?

A ten-person pilot found better quadriceps strength with nandrolone. Walking, sit-to-stand and the functional knee score did not clearly improve. The small sample and many statistical comparisons leave considerable uncertainty.¹¹⁵⁶

35 Has it been studied in rheumatoid arthritis?

Yes. A two-year study followed 47 postmenopausal women. Nandrolone improved some blood and body-composition measures, while bone measures did not improve and hoarseness was the main reported side effect.¹¹⁵⁷

36 Can it prevent muscle loss while a leg is immobilized?

In a study of 30 healthy young men, seven days in a leg cast reduced quadriceps size by about 6% in both groups. The studied nandrolone injection did not preserve muscle size or strength.¹¹⁵⁸

37 Is critical-illness recovery still being studied?

A 2025 protocol describes a larger placebo-controlled trial, GAINS 2.0, measuring mobility, strength and time out of hospital. A protocol explains what researchers plan to test; this paper contains no treatment results.¹¹⁵⁹

38 Does it improve recovery after a hip fracture?

A pilot trial randomized 23 older adults to nandrolone or placebo, alongside the same exercise and nutritional program. At 14 weeks, the main analysis found no significant difference in knee-extension strength between groups. Recruitment stopped early, leaving the trial smaller than planned.¹¹⁶¹

39 Does dialysis remove nandrolone?

A small Japanese study reported poor removal during dialysis. It followed 10 men receiving hemodialysis and also reported prolonged blood levels. This 1986 conference abstract gives limited assay and dialysis details.¹¹⁶²

40 What if I have a peanut or soy allergy?

The Australian Deca-Durabolin ampoule contains peanut oil. Its product information lists peanut or soy allergy as a contraindication.¹¹⁶³

41 Can it raise hematocrit?

Yes. The Australian product information warns about polycythemia, an increased concentration of red blood cells, and recommends checking hemoglobin and hematocrit during treatment.¹¹⁶³

42 Can it affect thyroid blood tests?

Anabolic steroids can lower thyroxine-binding globulin and total T4. The Australian label describes unchanged free thyroid hormone levels, so this blood-test pattern can occur without clinical thyroid dysfunction.¹¹⁶³

43 Will side effects stop as soon as I stop taking it?

They may persist. The Australian label says side effects cannot be quickly reversed by stopping the long-acting injection, and some voice changes can last or become permanent.¹¹⁶³

44 Can it affect mood or sleep?

Excitation, insomnia and depression appear in the historical US label. Psychiatric case reports include prolonged use of several steroids, making the responsible drug hard to identify.^1134,1164

45 Can it cause hair loss, and does finasteride change that?

The historical US label lists increased body hair and male-pattern baldness in women. The cited human evidence leaves the effects of combining nandrolone with finasteride or dutasteride unresolved.¹¹³⁴