Nandrolone (Deca-Durabolin)
Also known as: Deca, Deca-Durabolin, NPP, Nandrolone Decanoate, Nandrolone Phenylpropionate, Durabolin, Nandro, Nandrolon
19-nor steroid with a favourable anabolic-to-androgenic ratio, known for effects on joints and connective tissue — and for suppression that outlasts almost every other compound.
Substance family
Testosterone missing the carbon at position 19. They carry progestogenic activity and raise prolactin, which is why nipple and libido symptoms here need prolactin measured rather than an aromatase inhibitor. Suppression outlasts most other classes.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
Ester variants
Same active substance, same risk profile — only release rate and injection rhythm differ. The ester determines the timing, not the effect.
| Variant | Half-life | Injection interval |
|---|---|---|
| DecanoateDeca, Deca-DurabolinThe classic. Long carry-over means it must be stopped well before any planned recovery phase. | ~6–12 days | 1–2× / week |
| PhenylpropionateNPP, DurabolinSame substance, far more controllable. If prolactin side effects appear, stopping takes effect within days instead of weeks — at the cost of frequent injections. | ~2–3 days | Every 2–3 days |
The ester also determines how long the substance stays active after the last injection — relevant when planning a recovery phase.
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Medical (anemia, cachexia)
MedicalDose
50–100 mg / 2–4 weeks
Frequency
Every 2–4 weeks
Cycle length
Time-limited, medically supervised
Historically used for renal anemia and muscle wasting; today largely replaced by more modern therapies.
Mass building — Intermediate
IntermediateDose
200–400 mg / week
Frequency
Decanoate 1–2× / week, NPP every 2–3 days
Cycle length
12–16 weeks
Almost always alongside a testosterone base at least equal to the nandrolone dose. Most 'Deca dick' reports trace back to a base that is too low.
Joint support — lower dose
IntermediateDose
100–200 mg / week
Frequency
1–2× / week
Cycle length
8–12 weeks
Lower doses are often enough for the connective-tissue effect. SuppressionSuppressionThe body shutting down its own testosterone production because an external source is present., however, occurs at this level too — it does not scale down proportionally.
Higher doses
AdvancedDose
> 400 mg / week
Frequency
1–2× / week
Cycle length
Varies
ProgestogenicProgestogenicActing on the progesterone receptor — a property of 19-nor compounds that causes estrogen-like problems without high estradiol. side effects and the duration of suppressionsuppressionThe body shutting down its own testosterone production because an external source is present. increase markedly, without a proportional gain.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Erectile dysfunction and loss of libido ('Deca dick')
Countermeasure
Usually a consequence of an insufficient testosterone base or elevated prolactinprolactinA pituitary hormone that, when elevated, causes low libido, erectile problems and breast tissue growth., not of the nandrolone itself. Keep the testosterone base adequately high, have prolactin and estradiolestradiolThe main estrogen — needed in men too, and damaging in both directions when out of range. measured; tadalafil can bridge symptomatically. Mesterolone is the other common lever — it supplies the androgenic tone that 19-nor compounds lack, but it does nothing if prolactin is the actual cause.
Problem
Elevated prolactin, sensitive nipples
Countermeasure
Measure prolactinprolactinA pituitary hormone that, when elevated, causes low libido, erectile problems and breast tissue growth. before reaching for an aromatase inhibitoraromatase inhibitorA drug that blocks the conversion of testosterone to estradiol. — the cause here is usually progestogenicprogestogenicActing on the progesterone receptor — a property of 19-nor compounds that causes estrogen-like problems without high estradiol., not estrogenic. Cabergoline can be considered under medical guidance.
Problem
Very long-lasting suppression of the HPTA axis
Countermeasure
The decanoate esteresterA chemical chain attached to a steroid to slow its release from the injection site. releases for weeks — plan the recovery phase using the PCTPCTThe protocol after a cycle intended to restart the body's own testosterone production. timeline and stop far earlier than with short esters. Tamoxifen is part of a structured post-cycle plan; HCG preserves testicular function during the cycle.
Problem
Elevated hematocrit / thicker blood
Countermeasure
Cardio and adequate hydration; donate blood if markedly elevated. Monitor hematocrithematocritThe percentage of blood made up of red cells — rises on androgens and thickens the blood. and hemoglobin regularly. Nattokinase supports fibrinolysis but does not lower the cell count — donation remains the measure that works.
Problem
Unfavourable lipid profile (HDL drops)
Countermeasure
Milder than with trenbolone, but present: cardio, omega-3, possibly citrus bergamot. Check the lipid panel before and during.
Problem
Elevated blood pressure
Countermeasure
Measure at home, control salt and water balance, keep cardio in the plan. Medically, telmisartan, amlodipine or lisinopril, and low-dose tadalafil.
Problem
Masking of joint pain instead of healing
Countermeasure
The relief for joints is real, but it can hide existing injuries. Do not adjust loads upward on the basis of pain-free training alone.
Problem
Very long detection window in doping tests
Countermeasure
Nandrolone metabolites remain detectable for up to 18 months regardless of which esteresterA chemical chain attached to a steroid to slow its release from the injection site. was used. Unsuitable for anyone subject to testing.
Overview
Nandrolone is one of the oldest and best-studied anabolic steroids and, unlike trenbolone, it does have genuine medical approval — historically for renal anemia, osteoporosis and muscle wasting in chronic illness. That data basis makes it one of the few compounds in this field where long-term effects in humans have actually been described.
In the bodybuilding context, it is used in mass phases and is known above all for its perceived improvement in joint comfort. Its reputation as "mild" is only half accurate: side effects such as liver strain are indeed modest, but nandrolone suppresses natural testosterone production more persistently than almost any other substance.
Two esters are in common use. They contain the same active substance and differ only in release rate — everything below applies to both.
Mechanism of Action
Nandrolone is testosterone lacking the carbon atom at position 19, which shifts the ratio of anabolic to androgenic activity in favour of the anabolic effect. It aromatizes only to a small extent — roughly a fifth as strongly as testosterone — which is why estrogen-related side effects are less pronounced.
The decisive point is elsewhere: nandrolone has notable progestogenic activity and raises prolactin. Symptoms that look estrogenic — sensitive nipples, loss of libido, erectile problems — are therefore usually mediated by progesterone and prolactin. An aromatase inhibitor is the wrong response and, by crashing estradiol, tends to make the libido problem worse rather than better.
The improved joint comfort is attributed to increased collagen synthesis and water binding in the connective tissue. The effect is real, but it is symptomatic relief, not repair of a damaged structure.
Choosing an Ester
The choice between decanoate and phenylpropionate is a choice about controllability, not about effect.
Nandrolone is a substance whose characteristic side effects, particularly the prolactin-mediated ones, often only become apparent after several weeks. With the decanoate ester, a decision to stop takes weeks to have any effect. With phenylpropionate, it takes days. That difference matters more here than with most compounds, precisely because the problematic side effects show up late.
The trade-off is frequency. Injections every two to three days over ten weeks add up, and the cumulative strain on injection sites is a real factor. This is the main reason many people accept the decanoate ester despite its far longer tail.
One thing the shorter ester does not change: the detection window in doping tests. Nandrolone metabolites remain traceable for months regardless of the ester.
Typical Context
Nandrolone is used in longer mass phases, essentially always alongside a testosterone base. The rule of thumb that has proven itself is to keep the testosterone dose at least at the level of the nandrolone dose — a large share of reported libido and erectile problems trace back to violating it.
The long tail of the decanoate ester is the point most often underestimated. Anyone planning a recovery phase must stop nandrolone substantially earlier than a short-ester compound — otherwise the post-cycle plan starts while active substance is still circulating.
Side Effects & Risks
- Very long-lasting suppression of the body's own testosterone production
- Erectile dysfunction and loss of libido, especially with an insufficient testosterone base
- Elevated prolactin with progestogenic effects on breast tissue
- Increase in hematocrit and hemoglobin
- Shift in the lipid profile (HDL drops), less pronounced than with trenbolone
- Elevated blood pressure, mainly via water retention
- Masking of joint pain, with the risk of training through an existing injury
- Mood changes; depressive episodes are described in the literature
- Detectability in doping tests for up to 18 months
Blood Work & Monitoring
- Total/free testosterone — to verify the base is adequate
- Prolactin — the key marker for libido and nipple symptoms
- Estradiol (sensitive) — do not crash it; it is needed for libido
- Hematocrit & hemoglobin — checking for polycythemia
- Lipid profile (LDL, HDL, triglycerides)
- Blood pressure — measured at home
- Liver values (ALT, AST, GGT) — usually unremarkable, but part of the baseline
Harm-Reduction Notes
- Keep the testosterone base at least at the level of the nandrolone dose
- On nipple or libido symptoms, check prolactin first — an aromatase inhibitor is the wrong lever here
- With the decanoate ester, stop far earlier than with short-acting compounds and plan the recovery phase using the PCT timeline
- If controllability matters, choose phenylpropionate — stopping actually works within days there
- Do not interpret improved joint comfort as healing; keep load progression conservative
- Not suitable for anyone subject to doping controls — the detection window spans months
- Sterile single-use needles, rotate injection sites
- A post-cycle plan should be in place before the first injection
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Schedule III controlled substancePrescription required; possession without one is a federal offence. |
| EU / UK | Prescription-only medicineApproved for defined medical indications; supply without prescription is an offence. |
| Canada / Australia | Controlled substance, prescription-onlyImport for personal use is restricted. |
| Parts of Asia & Latin America | Pharmacy availability variesSome countries treat it as pharmacy-dispensed rather than strictly prescription-bound. Enforcement is inconsistent and rules change. |
| Competitive sport | Prohibited at all timesListed by WADA; national anti-doping law applies in addition. |