Nandrolone
Deca-Durabolin (decanoate) / NPP (phenylpropionate); 19-nortestosterone
Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Schedule III; FDA-approved (US) only for anemia of chronic kidney disease
- WADA
- Prohibited at all times (S1 Anabolic Agents). Nandrolone metabolites are a classic long-window anti-doping finding.
Reference only. Not medical advice.
This is something to take to a clinician. The Atlas can tell you what is known about nandrolone in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Nandrolone is 19-nortestosterone, a testosterone derivative lacking the 19-methyl group. As the long-acting decanoate ester (Deca-Durabolin) it is one of the few AAS with a retained FDA indication, anemia of chronic kidney disease, and it has a documented history in cachexia/wasting and osteoporosis research. Its 19-nor structure produces progestogenic activity and a metabolite that can blunt erectile function and libido even when total testosterone looks adequate, the phenomenon users call 'deca dick.' The phenylpropionate ester (NPP) is shorter-acting.
A genuine medical drug for anemia and wasting, and the origin of 'deca dick.'
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
- Anemia of chronic kidney disease
- The remaining US-approved indication; stimulates erythropoiesis in select dialysis-era patients.
- Historical wasting/osteoporosis use
- Studied for cachexia, post-menopausal osteoporosis and corticosteroid-induced catabolism before modern alternatives.
How it is supposed to work
Nandrolone binds the androgen receptor to drive muscle protein synthesis and erythropoiesis. Unlike testosterone it is a poor substrate for 5-alpha-reductase, and in tissues where it is reduced it forms a weaker androgen, part of why it was marketed as comparatively 'mild' androgenically. However, it possesses notable progesterone-receptor activity, contributing to suppression and sexual side effects.
Identical to testosterone but for removal of the carbon-19 methyl group ('19-nor'), which alters receptor binding and metabolism and confers progestogenic character.
Why 'deca dick' happens
Nandrolone strongly suppresses the HPTA (lowering endogenous testosterone) while its progestogenic activity and its reduced metabolite can impair central and peripheral mechanisms of erection and libido. The result is sexual dysfunction that can persist even when bloodwork is manipulated to look normal, a frequently reported, poorly appreciated harm.
Safety in detail
This intervention involves significant physiological effects and requires evaluation and monitoring by a qualified physician. Self-administration without medical oversight carries documented health risks.
- Pronounced HPTA suppression with slow recovery owing to the long ester.
- Sexual dysfunction ('deca dick') from progestogenic activity and suppression.
- Polycythemia from erythropoietic stimulation.
- Adverse lipid changes and cardiovascular risk shared with the AAS class.
- Long detection window, a frequent anti-doping positive.
Replacement is not the same as a cycle
The approved anemia dose is modest and monitored. Physique use applies supraphysiological doses for which sexual dysfunction, polycythemia, prolonged suppression and cardiovascular harm are documented. This entry does not provide such dosing.
What it does to fertility
Strongly suppresses LH/FSH and spermatogenesis. The long decanoate ester means suppression, and impaired fertility, can persist for an extended period after the last dose; recovery is variable.
What has to be monitored
The bloodwork this needs, and the reason it belongs with a clinician rather than a website.
- Hematocrit/hemoglobin
- Lipid panel
- LH/FSH, total testosterone
- PSA where indicated
- Blood pressure
What people get wrong
Often said'Deca is mild because it is less androgenic'
ActuallyLower androgenic 'rating' does not mean low-risk: nandrolone is strongly suppressive, progestogenic, and is associated with marked sexual dysfunction ('deca dick') and the same cardiovascular/lipid concerns as other AAS.
Often said'Deca dick is a myth'
ActuallyNandrolone-associated erectile and libido suppression is a well-recognized, mechanistically plausible effect of its HPTA suppression and progestogenic activity.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
How we got here
Nandrolone esters were introduced clinically in the late 1950s-1960s (Organon's Deca-Durabolin). It became a workhorse of anemia and wasting therapy and one of the most-studied AAS, while simultaneously becoming a mainstay of illicit physique use. Its long detection window made it a frequent positive in sports anti-doping testing.
- ~1960Nandrolone decanoate (Deca-Durabolin) introduced by Organon
- 1960s-1990sUsed clinically for anemia, wasting, osteoporosis
- 1990Schedule III in the US
- 2000sNarrowing of approved indications as alternatives emerged
At a glance
- Class
- 19-nortestosterone derivative
- Esters
- Decanoate (long), phenylpropionate/NPP (short)
- Decanoate half-life
- ~6-12 days (ester-dependent)
- FDA indication
- Anemia of chronic kidney disease
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Nandrolone. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- What can go wrong. We have not written the risk line for this one. Read the safety section below rather than treating its absence as reassurance.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Frisoli et al., nandrolone decanoate in osteoporosis2005
Documented bone and lean-mass effects in older women, illustrating the legitimate-medicine lineage.
Pope et al., Endocrine Society Scientific Statement2014
Places 19-nor agents within the broader AAS cardiovascular/endocrine harm profile.