Nandrolone Phenylpropionate

evidence score

anabolic

Scheduled Substance

299 studies

NPPDurabolinnandrolone PP+1 more

Nandrolone Phenylpropionate (NPP) is a short-acting ester of nandrolone (19-nortestosterone), a synthetic anabolic steroid with high anabolic-to-androgenic ratio (~3:1 vs testosterone). Approved in some countries for anemia, osteoporosis, and muscle-wasting diseases. NPP's 4-5 day half-life requires twice-weekly injections but clears faster than Deca-Durabolin (decanoate ester). Highly anabolic with lower androgenicity and minimal DHT conversion; however, strongly suppressive and notable for "Deca dick" (progesterone-mediated libido/erectile dysfunction). Significant collagen synthesis increases benefit connective tissue. Schedule III controlled substance.

Evidence

Moderate evidence

Safety

Unknown safety profile

Clinical Status

Approved

Research Sync

Feb 19, 2026

Dosing

Typical

300 mg

100 mgRange600 mg

FrequencyTwice weekly intramuscular injection

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Pharmacology

Half-life~4–5 days

Onset1–2 weeks for strength; 4–6 weeks for muscle mass changes

DurationSuppression persists 3–4 months post-cycle without PCT

Routes

intramuscular

Evidence Score

Level B — Moderate

299 studies indexed · 1 meta-analysis

Scoring Factors

Volume(40%)~50/100

Quality(30%)~43/100

Sample Size(10%)~100/100

Consistency(10%)~100/100

Replication(5%)~100/100

Recency(5%)~100/100

Scores estimated from study counts. Exact breakdown computed after research sync.

Evidence Levels

AScore ≥75 with at least 1 meta-analysis and 3+ RCTs

BScore ≥50 with at least 1 RCT or meta-analysis

CScore ≥25 — observational or animal evidence only

DScore <25 — very limited or preclinical data

Plain-English Snapshot

Nandrolone Phenylpropionate is currently categorized as a anabolic compound.

Evidence is moderate (67/100): promising signal from 299 indexed studies, but context and population still matter.

Safety scoring is incomplete. Start conservatively and monitor carefully.

Core mechanism

Highly anabolic 19-nor androgen; partial AR agonist with progestogenic activity; minimal aromatization; high anabolic-to-androgenic ratio via tissue-specific AR binding

Practical Context

Strongest current signals

Level D: The use of anabolic androgenic steroids appears to have a negative impact on erectile function and male reproductive health, with evidence of hypogonadism and hormonal alterations.
Level D: In both groups, PE was associated with ED, LL, poor subjective health, sexual dissatisfaction and a more negative sexual self-concept, suggesting a comparable psychological burden in l/a PE and s/v PE and emphasises that PE should be diagnosed at an early stage.
Level D: There is some evidence that testosterone replacement leads to symptom relief, particularly with respect to muscle strength, bone mineral density, and erectile dysfunction, and exogenous androgens have not been consistently shown to have antidepressant activity.

Elevated caution signals

2 severe/high side effect flags