NPP (Nandrolone Phenylpropionate) — Dosing, Cycles, Half-Life & Side Effects
NPP (Nandrolone Phenylpropionate) is an injectable 19-nortestosterone derivative with a half-life of 2.7 days. Short-ester nandrolone for mass and joint relief. Complete HPTA shutdown with persistent metabolites (same as Deca). Primary risks include strong HPTA suppression, prolonged 19-nor metabolite clearance affecting PCT timing. This page is educational harm-reduction reference compiled from peer-reviewed literature — not medical advice, not an endorsement, not a recommendation to use. Consult a licensed clinician before any decision.
Quick Facts
| Class | 19-nor Injectables |
|---|---|
| Half-life | 2.7 days |
| Detection window | 360 days |
| Aromatization | Mild |
| Hepatotoxicity | None |
| Suppression | 10/10 |
| 17α-alkylated | No |
| 19-nor structure | Yes (extended metabolite clearance) |
| Administration | injectable |
Typical Dosing Ranges
Common dose range: 200-400mg/week
Cycle length: 8-12 weeks
Time to steady state: ~12 days
Dose ranges are compiled from published pharmacokinetic studies and community-reported usage. Where a value is community-reported rather than clinically studied, this page and its structured data flag it. Lower end of any range is always the safer starting point.
Stacking Considerations
- 19-nor compound — avoid stacking with another 19-nor (nandrolone/trenbolone) unless you accept extended and overlapping metabolite clearance.
- Incompatible combinations per internal rule set: tren-ace, tren-enan, finasteride, dutasteride.
PCT Requirements
- This compound causes clinically meaningful HPTA suppression. Post-cycle therapy is recommended.
- As a 19-nor, metabolites persist for weeks after last dose — PCT start should be delayed until apparent half-life clearance plus adequate wash-out (typically 4–6+ weeks post-last-injection for nandrolone; longer for trenbolone-dominant stacks).
- Depot clearance estimate: ~13 days post-last-dose before SERM start (5 × apparent depot half-life of 60h).
- Never stack two SERMs. Extend a single SERM (tamoxifen OR enclomiphene/clomiphene) rather than combining.
- Use the cycle planner to generate a full protocol based on your complete stack, not this compound alone.
Side Effect Profile
- Frequent injections
- 19-nor side effects
- Prolactin issues
- Long recovery
Known Interactions
Deca Durabolin (Nandrolone Decanoate) + Trenbolone Acetate
moderate — hormonalBoth are 19-nor compounds affecting prolactin and progesterone. Compounding effects on HPTA.
Recommendation: Consider prolactin management (cabergoline/P5P). Recovery may be prolonged.
Monitor: Prolactin, Progesterone, LH, FSH
Deca Durabolin (Nandrolone Decanoate) + Tamoxifen (Nolvadex)
moderate — hormonalTamoxifen may up-regulate progestin receptors when used with 19-nor compounds.
Recommendation: Consider enclomiphene as alternative SERM for PCT after nandrolone cycles.
Monitor: Progesterone, Prolactin, LH, FSH
Related compounds
Anadrol (Oxymetholone)
Orals · t½ 8-9 hours
Anavar (Oxandrolone)
Orals · t½ 8-9 hours
Deca Durabolin (Nandrolone Decanoate)
19-nor · t½ 6-12 days (apparent depot terminal half-life; free nandrolone elimination ~4.3h after de-esterification; Minto CF et al. 1997 PMID 9103484)
Dianabol (Methandrostenolone)
Orals · t½ 3-6 hours
Monitoring (Bloodwork & Vitals)
- Comprehensive metabolic panel (baseline, mid-cycle, post-cycle)
- Lipid panel (total cholesterol, HDL, LDL, triglycerides)
- CBC (hemoglobin, hematocrit — watch for erythrocytosis)
- Sex-hormone panel (Total T, Free T, Estradiol sensitive, SHBG, LH, FSH)
- Blood pressure (weekly self-check; flag systolic >140 or diastolic >90)
Baseline bloodwork is recommended before any cycle. Discontinue if liver enzymes exceed 3× upper limit of normal or if hematocrit exceeds 54%.
Frequently Asked Questions
What is the half-life of NPP (Nandrolone Phenylpropionate)?
NPP (Nandrolone Phenylpropionate) has a half-life of approximately 2.7 days. Clearance estimate: 60h � 5 = 300h = 12.5 days. This figure is used to determine injection frequency (for esters) and post-cycle clearance timing.
What is the typical dose range for NPP (Nandrolone Phenylpropionate)?
Commonly reported ranges for NPP (Nandrolone Phenylpropionate): 200-400mg/week. Cycle length: 8-12 weeks. These are compiled from published studies and community-reported usage — individual response varies and lower end is always preferred.
Does NPP (Nandrolone Phenylpropionate) suppress natural testosterone?
NPP (Nandrolone Phenylpropionate) causes severe suppression of the HPTA axis (score 10/10). Post-cycle therapy (PCT) is recommended after use. As a 19-nor compound, metabolites persist for weeks-to-months and shift PCT timing later than non-19-nor cycles.
Does NPP (Nandrolone Phenylpropionate) aromatize to estrogen?
Aromatization profile: Mild. Minimal to no aromatization expected, so aromatase inhibitors are not typically indicated for this compound alone.
What is NPP (Nandrolone Phenylpropionate) typically used for?
NPP (Nandrolone Phenylpropionate) is commonly used for: Bulking, Joint support, Mass building. Intended-use context does not imply safety — every use case carries the same underlying pharmacological risks.
Citations
- Belkien L et al.. 1985. Pharmacokinetics of 19-nortestosterone esters — Practical half-life 2.5-4.5 days for NPP; shorter ester chain than decanoate with more frequent dosing
- Minto CF et al.. 1997. J Pharmacol Exp Ther — Pharmacokinetics and pharmacodynamics of nandrolone esters in oil vehicle
- de Oliveira Vilar Neto JF et al.. 2021. Andrologia — Systematic review: only 4/38 known-outcome AAS-induced hypogonadism cases fully recovered; 19-nor compounds associated with prolonged suppression
- Liu et al.. 2025. Substance Use & Misuse — AAS meta-analysis: SBP +12.43 mmHg (95% CI: 9.59-15.26), LDL-C +9.12 mg/dL (95% CI: 6.75-11.49)
- Handelsman DJ / Shankara-Narayana N et al.. 2022. Eur J Endocrinol — 19-nor HPTA recovery median 52 weeks; NPP suppression equivalent to decanoate (same active compound, different ester) - supports suppressionScore 10/10
- Hartgens F, Kuipers H. 2004. Sports Medicine — NPP shares nandrolone's low aromatization (~20% vs. testosterone); progesterone-receptor agonism drives prolactin risk - supports aromatizationRate 2/10
- Geusens P. Nandrolone decanoate: pharmacological properties and therapeutic use in osteoporosis. Clin Rheumatol. 1995. PMID: 8846659
- Beiner JM, et al. The effect of anabolic steroids and corticosteroids on healing of muscle contusion injury. Am J Sports Med. 1999;27(1):2-9. PMID: 9934411
Disclaimer
StackItSmart is an independent harm-reduction reference. The content above is compiled from peer-reviewed literature and is not medical advice, not an endorsement, and not a recommendation to use NPP (Nandrolone Phenylpropionate). Performance-enhancing compounds carry legal, endocrine, cardiovascular, and hepatic risks. Consult a licensed clinician before any decision. StackItSmart does not provide sourcing, procurement, or dosing prescriptions.