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 |
06 Commonly used with
What nandrolone is combined with, and why. This is about intent rather than safety — the interactions table below covers what is dangerous. Nothing here is listed without what it costs.
| Compound | Frequency | Purpose & trade-off |
|---|---|---|
| Stacked compounds | ||
| Testosteronebase | Testosterone is run as the base to preserve libido and erectile function that nandrolone alone suppresses.Trade-off: Adds its own aromatisation and estrogenic load requiring separate management. | |
| Support & ancillaries | ||
| Cabergolinedopamine agonist | Controls prolactin elevation from the 19-nor to prevent prolactin-driven gyno and sexual dysfunction.Trade-off: Can cause nausea, low blood pressure and fatigue, and over-suppressing prolactin has its own downsides. | |
| AnastrozoleAI | Manages estrogen from the testosterone base, since nandrolone side effects are worsened by high estrogen.Trade-off: Crashing estrogen alongside a 19-nor can severely impair libido and mood. | |
| hCGon-cycle | Maintains testicular function during the deep, prolonged suppression that decanoate causes.Trade-off: Raises estrogen conversion and adds cost and injections to an already suppressive protocol. | |
| Post-cycle | ||
| ClomifenePCT | Drives LH and FSH to restart natural production after the long decanoate ester clears.Trade-off: Nandrolone's heavy, prolonged suppression makes recovery slow and sometimes incomplete despite PCT. | |