Compound profile
Nandrolone
Also known as Deca-Durabolin, Deca, Nandrolone decanoate, Nandrolone phenylpropionate (NPP)
Last reviewed October 2026
Educational only. A summary of published research, not medical advice or a recommendation. No doses are listed.
Quick take
An injectable steroid closely related to testosterone (a “19-nor” steroid), once used medically to treat anemia and muscle wasting.
- Class
- Anabolic steroids
- Status
- Previously approved
- Evidence
- Early or small human studies
- Half-life
- About 6–12 days (decanoate ester)
Mechanism fingerprint
What it acts on, and how. Each chip links to that pathway on the map.
Binds the androgen receptor strongly, but is converted to a weaker androgen in skin and scalp than testosterone is. It also acts on progesterone receptors, which is linked to some of its side effects.
What makes it different
A “19-nor” steroid: unlike testosterone, it becomes a weaker androgen in skin and scalp, and it also acts on progesterone receptors.
Compare side by side
Mechanism & pathways
-
Agonist
Androgen receptor
Receptor for testosterone and DHT. Activating it builds muscle and drives male traits such as body hair and a deeper voice. Every anabolic steroid binds it.
-
Acts on
Progesterone receptor
Receptor for the hormone progesterone. Some “19-nor” steroids also act on it, which is linked to some of their side effects.
-
Converted by
5α-reductase
makes a weaker androgen
An enzyme that converts testosterone into DHT, a stronger androgen, in skin, scalp and prostate. It turns nandrolone into a weaker androgen instead.
Evidence overview
Early or small human studies
Older clinical trials in anemia, HIV-related wasting and kidney disease showed gains in lean mass and red blood cells. Bodybuilding use hasn't been studied in safety trials.
A breakdown into human, animal and cell studies hasn't been added for this compound yet.
Why it's used
Medically, it raised red blood cell counts in kidney failure and helped people regain lean mass in wasting illnesses. Bodybuilders use it for size and weight gain.
Side effects & risks
Reported side effects
- Water retention
- Lower libido and erectile problems
- Breast tissue growth (gynecomastia)
- Higher red blood cell count
- Acne
Risks and warnings
- Shuts down the body's own testosterone production: testicles shrink and sperm counts fall, and recovery after stopping can take months or be incomplete.
- Lowers HDL (“good”) cholesterol and raises LDL, adding to heart disease risk.
- Long-term use is linked to high blood pressure, heart muscle damage (cardiomyopathy), heart attacks and early death.
- Irritability and aggression while using, and depression after stopping; dependence can develop.
- In women: masculinizing effects (deeper voice, facial and body hair, clitoral enlargement) that can be permanent.
- In teenagers, can close growth plates early and stunt final height.
- Underground-lab products are often mislabeled or contaminated, and non-sterile injections can cause abscesses and infections.
- Schedule III controlled substance in the US: illegal to possess without a prescription.
- Prohibited in sport by the World Anti-Doping Agency (WADA).
FAQ
Short answers taken from this profile.
What is Nandrolone?
An injectable steroid closely related to testosterone (a “19-nor” steroid), once used medically to treat anemia and muscle wasting.
How does Nandrolone work?
Binds the androgen receptor strongly, but is converted to a weaker androgen in skin and scalp than testosterone is. It also acts on progesterone receptors, which is linked to some of its side effects.
What receptors or pathways does Nandrolone act on?
androgen receptor (agonist), progesterone receptor (acts on) and 5α-reductase (converted by; makes a weaker androgen).
How is Nandrolone different from similar compounds?
A “19-nor” steroid: unlike testosterone, it becomes a weaker androgen in skin and scalp, and it also acts on progesterone receptors.
What is the half-life of Nandrolone?
About 6–12 days (decanoate ester).
Is Nandrolone approved?
Was FDA-approved for anemia of kidney disease, but hasn't been marketed in the US since 2002; still a prescription medicine in some other countries.
What has Nandrolone been studied for?
Medically, it raised red blood cell counts in kidney failure and helped people regain lean mass in wasting illnesses. Bodybuilders use it for size and weight gain.
How strong is the evidence?
Early or small human studies. Older clinical trials in anemia, HIV-related wasting and kidney disease showed gains in lean mass and red blood cells. Bodybuilding use hasn't been studied in safety trials.
What are the main risks?
Shuts down the body's own testosterone production: testicles shrink and sperm counts fall, and recovery after stopping can take months or be incomplete. Lowers HDL (“good”) cholesterol and raises LDL, adding to heart disease risk. Long-term use is linked to high blood pressure, heart muscle damage (cardiomyopathy), heart attacks and early death. More are listed under risks and warnings.
Sources
- Johansen KL et al. Anabolic effects of nandrolone decanoate in patients receiving dialysis: a randomized controlled trial. JAMA 1999.
- Federal Register, 2010: Deca-Durabolin was not withdrawn from sale for reasons of safety or effectiveness.
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol 2008.
- Pope HG et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev 2014.