This information is for research and educational purposes only. No medical recommendations. Products are not approved for human use. For health questions, consult a doctor.

Lexicon

Muscle & performance

Deca (Nandrolone Decanoate)

The classic bulk staple - slow, mild building with a joint reputation.

1 min read 2 sources Titration Updated June 2026
Class
19-nor anabolic (long decanoate ester)
Use
Intramuscular or subcutaneous, 1-2x per week
Half-life
about 6-12 days
WADA
banned (anabolic)

Getting started

Typical dosing (research context)

Per-week figures in mg, split across 1-2 injections. Long ester, slow build over weeks.

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What is Deca?

Deca (Nandrolone Decanoate) is one of the oldest and best-known anabolics - a 19-nor steroid with a long decanoate ester. It builds slowly and comparatively mildly, is known for the reputation of making joints feel "smoother", and was used clinically for muscle wasting, anemia and osteoporosis.

This information is for research and educational purposes only. No medical advice.

How it works

Nandrolone activates the androgen receptor, aromatizes only weakly (less estrogen than testosterone), but - like all 19-nor compounds - has progesterone activity. That is the reason for the prolactin-related nickname "deca dick" (libido/erection issues) when prolactin is not controlled.

Use and dosing

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What the research shows

Nandrolone decanoate has an unusually good clinical data base compared to other anabolics. The Johansen study (JAMA, 1999) showed a significant gain in fat-free mass on nandrolone vs placebo in dialysis patients. The AAS pharmacology is summarized in Kicman (2008).

Side effects

  • Prolactin: "deca dick" - libido/erection issues, cabergoline as countermeasure.
  • HPTA suppression: strong and long-acting - longer PCT needed.
  • Estrogen: weak aromatization, an AI may still be needed.
  • Water retention, blood pressure.

Storage

Store the oil solution at room temperature, protected from light - no fridge needed. Out of reach of children.

Practice

PCT / after coming off

Anabolic substances suppress the body's own testosterone production in the research context. Anyone who comes off a cycle (rather than running it continuously) typically uses a post-cycle therapy (PCT) to restart the natural axis (HPTA).

The standard scheme in the research/literature context combines a SERM (tamoxifen and/or clomifene, alternatively enclomiphene) over roughly four weeks, optionally preceded by HCG to re-sensitise the testes before the SERM block. An aromatase inhibitor (anastrozole/exemestane) belongs more to on-cycle estrogen control than to the PCT itself.

19-nor note: nandrolone and trenbolone are progestagenic and can raise prolactin. The literature additionally discusses a prolactin-lowering agent (cabergoline) and a somewhat longer wash-out window here.

Tip: order the PCT items together with the cycle so they are already on hand when you come off.

This information serves research and educational purposes only. Not medical advice.

Evidence

Sources

  1. 1 Anabolic effects of nandrolone decanoate in dialysis patients - randomized trial. Johansen et al., JAMA, 1999
  2. 2 Pharmacology of anabolic steroids - comprehensive review. Kicman, Br J Pharmacol, 2008

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