Nandrolone Decanoate
A long-acting ester of nandrolone (19-nortestosterone), the most-studied 19-nor anabolic. Added to testosterone protocols for lean mass and joint comfort, with a progestogenic side-effect profile and a very long detection window as the cost.
01 Overview
Nandrolone differs from testosterone by a single missing carbon at the 19 position, which sharply reduces its conversion to DHT and its aromatisation. The decanoate ester gives a ~7 day half-life.
Much of its reputation for joint relief is real but poorly isolated in controlled work; its reputation for sexual dysfunction is better established and stems more from low DHT than from prolactin alone.
02 Mechanism
Nandrolone is an androgen-receptor agonist with high anabolic and low androgenic activity. Its 19-nor structure means it reduces to the weak androgen DHN rather than DHT, and aromatises only weakly — but to the more potent oestrogen-like effects it does produce, it adds progestogenic activity at the progesterone receptor.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Therapeutic | 50–100 mg/wk | IM | Licensed for anaemia of renal insufficiency and wasting. Given fortnightly at the low end. |
| Common | 200–400 mg/wk | IM | Typical addition to a testosterone base for a mass phase. |
| High | 400–600 mg/wk | IM | Higher joint-comfort and mass returns; progestogenic side effects scale with it. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased lean body massWell documented in wasting and renal-anaemia populations | +2–4 kg / cycle | Clinical | |
| Improved joint comfortConsistently reported; mechanism plausibly collagen and synovial fluid, not isolated in controlled work | Marked (reported) | Anecdotal | |
| Raised red cell massThe basis of its licensed use in renal anaemia | Dose-dependent | Clinical | |
| Increased bone mineral densityStudied in osteoporosis before bisphosphonates | +3–5% | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Sexual dysfunction ("deca dick")Erectile difficulty and low libido, even with adequate testosterone alongside. More about low DHT than prolactin, contrary to the common account. | Moderate | Common | Observational | |
| HPTA suppressionStrong and prolonged suppression of the natural axis; recovery is slower than with testosterone. | Severe | Universal | Clinical | |
| Progestogenic gynaecomastiaBreast tissue growth driven by progestogenic rather than purely oestrogenic activity, so it does not always respond to an aromatase inhibitor. | Moderate | Uncommon | Observational | |
| Very long detection windowMetabolites are detectable for up to 12–18 months — the longest of the common compounds. Relevant to any tested sport. | Mild | Universal | Clinical |