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Muscle & performance

NPP (Nandrolone Phenylpropionate)

The fast Deca - the same nandrolone molecule with a short ester.

1 min read 9 sources

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Glass vial with pale yellow oil and a black TPD label on a white podium, next to it a glossy blue 3D steroid molecule in a bright lab, symbolic image for nandrolone phenylpropionate
Approved · since 1959

Summary

At a glance

Sources checked on 26 Oct 2026

Pilot trial before prostate surgery
54 men

Fewer complaints 24 hours after surgery than with placebo2

Body protein in 10 days
+9 %

Rats, at the lowest and the highest level3

Body fat, highest level
-32 %

Rats, 10 days, body weight stayed the same3

With the long ester (decanoate)
+4.5 kg

Lean mass in 6 months in dialysis, placebo +1.9 kg4

On the registry
0 trials

no trial with nandrolone phenylpropionate on ClinicalTrials.gov, as of 26 Oct 20268

  • NPP is nandrolone with a short phenylpropionate ester. Like Deca it acts on the androgen receptor, which nandrolone bound more strongly than testosterone in experiments.95
  • In a direct comparison of the esters the nandrolone level peaked earlier and higher with phenylpropionate than with decanoate. Own testosterone was suppressed fastest but only briefly.1
  • In a small randomised trial older men before prostate surgery had fewer complaints 24 hours afterwards than with placebo, after 48 hours the difference was no longer significant.2
  • In rats body protein rose by 9 percent in 10 days and at the highest level body fat fell by 32 percent. Larger human trials exist almost only for the long decanoate ester.34
  • According to ChEMBL nandrolone phenylpropionate has been approved since 1959. The registry lists no trial. Everything here is the state of research, not a recommendation.98
Profile

Updated June 2026

How long does it stay in the body?

Share left after one dose, calculated with a half-life of ~2.5 days

Half-life ~2.5 days
After 5 days: 25 %
Day 2, next dose · 57 %Day 2.5 · 50 %Day 5 · 25 %Day 7.5 · 12.5 %Day 12.5 · 3.1 %

Simplified model without an absorption phase, half-life from the TPD lexicon. The lexicon gives 2 to 3 days, we calculate with the middle.

Class
19-nor anabolic

short phenylpropionate ester

Use
Intramuscular

every other day

Half-life
about 2-3 days
WADA
banned

anabolic

Sizes
2 sizes

100mg/ml, 150mg/ml

Contents 14 sections
  1. At a glance
  2. What is NPP?
  3. How it works
  4. NPP vs Deca
  5. Dosing
  6. What the research shows
  7. Research status
  8. Side effects
  9. Storage
  10. PCT / after coming off
  11. Related compounds
  12. FAQ
  13. Glossary
  14. Sources

What is NPP?

NPP (Nandrolone Phenylpropionate) is the exact same nandrolone molecule as Deca, just with a short phenylpropionate ester. It rises and clears faster than Deca - meaning more frequent injections, but faster control and faster onset.

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

How it works

Identical to Deca: androgen receptor activation, weak aromatization, progesterone activity (prolactin topic). Only the kinetics differ.

Where it acts

Where NPP acted in studies

Tap a point or a card. Grey = observed, partly in animal studies.

  1. Calf muscle (rat)

    Muscle mass and protein rose at all levels3

    Observed in trials
  2. Fat tissue (rat)

    Body fat -32% at the highest level3

    Observed in trials
  3. Testes and hormone axis

    Own testosterone suppressed quickly but only briefly1

    Observed in trials

Targets in the ChEMBL database9

Compound CHEMBL1200412: one recorded mechanism, agonist with direct binding to the human receptor.

Androgen receptor
Gene
AR
UniProt
P10275
ChEMBL
CHEMBL1871
Action
Agonist, direct binding
Glossy blue 3D molecules drip from a glass pipette and dock onto binding sites between light blue fibres and a transparent joint
The short ester releases nandrolone quickly, it acts on the androgen receptor. Symbolic image.

NPP vs Deca

  • NPP: short, every other day, faster onset, fast out - popular for those who want to try nandrolone or control it quickly.
  • Deca: long, 1-2x per week, more convenient, builds over weeks.

Comparison

Short and long ester

The same compound at the same receptor with esters of different length, as stated in the TPD lexicon. Tap a card to open its entry.

Short ester NPP (Nandrolone Phenylpropionate) AR
Mix of both esters NandroMix 300 AR Long ester Deca (Nandrolone Decanoate) AR Testosterone, same ester Testosterone Phenylpropionate AR

In a direct comparison the level with phenylpropionate peaked earlier and higher, suppression of own testosterone came faster and lasted shorter than with decanoate. 1

Dosing

Dosing

Dosing, titration and syringe

Loading the dosing information …

  • Getting started and stepping up, drawn as a staircase
  • Units on the U-100 syringe for every step
  • How long one vial lasts

What the research shows

Nandrolone research (Johansen, JAMA 1999) applies to both esters equally - once the ester is cleaved, the same nandrolone acts. AAS pharmacology: Kicman 2008.

Study results

What the trials measured

Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.

Complaints after prostate surgery2

Questionnaire points, lower is better, 54 men with a mean age of 70

After 24 hours2
Placebo 9.77 Punkte
Nandrolone phenylpropionate 6.18 Punkte
After 48 hours2 not significant
Placebo 5.55 Punkte
Nandrolone phenylpropionate 4.48 Punkte

One injection before surgery against placebo in sesame oil. The questionnaire covered urinary complaints, wound pain and satisfaction. According to the trial no complication was due to the compound.

Body composition in rats3

Change in percent after 10 days, female rats, three levels

Body protein3 lowest level
Nandrolone phenylpropionate +9%
Body protein3 highest level
Nandrolone phenylpropionate +9%
Body fat3 highest level
Nandrolone phenylpropionate -32%

At the lowest level weight rose without more fat, at the highest weight stayed the same. Calf muscle mass and protein rose at all levels, muscle protein synthesis only at the two lower ones.

The same compound with the long ester4

Lean mass in kg after 6 months, 29 people on dialysis

Dialysis trial4
Placebo +1.9 kg
Nandrolone decanoate (long ester) +4.5 kg

The trial tested nandrolone decanoate, not NPP. Once the ester is split off both release nandrolone, only the release speed differs.

Transparent block model of tissue: a light blue cartilage layer on top, porous bone underneath, on a white background
There are few human trials on NPP itself, much comes from animal studies. Symbolic image.

Research status

Where the research stands

ClinicalTrials.gov lists no trial for nandrolone phenylpropionate. As of 26 Oct 2026. 8

  1. Preclinical Muscle and body fat in rats
  2. Phase 1 no registered trial
  3. Phase 2 no registered trial
  4. Phase 3 no registered trial
  5. Approval since 1959
Approved: ChEMBL lists nandrolone phenylpropionate with phase 4 as the highest phase and first approval in 1959.9

The approval predates today's trial registries, so the register shows no current trial for this form. 8

Side effects

  • Prolactin - cabergoline as countermeasure.
  • Strong HPTA suppression - PCT topic.
  • Weak aromatization, AI if needed.
  • Injection site irritation more common due to the short ester.

Storage

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

Four glass vials with golden oil on a white shelf, next to them a folded light blue cloth
Oil solution at room temperature and protected from light, no fridge needed. Symbolic image.
Level · NPP (Nandrolone Phenylpropionate)

How the level builds up

One dose every other day: each dose adds to what is left of the previous one.

Lexicon: Intramuscular, every other day
Peak 2.35×Trough 1.35×
Day 10 · 6. dose
2.27× of the first dose
Plateau
from Day 10

96 % of the plateau after dose 6

Peak
2.35×

of the first dose

Trough
1.35×

before the next dose

Simplified model, values relative to the first dose, no dosing information. Dashed: the first dose alone, green: the plateau.

Related

Related compounds

Same receptors or blends with NPP (Nandrolone Phenylpropionate): all in the TPD lexicon.

NPP (Nandrolone Phenylpropionate)
Deca (Nandrolone Decanoate) The same nandrolone, long ester NandroMix 300 Contains NPP plus nandrolone decanoate Test/NPP Mix 150 Contains NPP plus testosterone propionate Testosterone Phenylpropionate Testosterone with the same ester Testosterone Propionate Testosterone with a short ester Trenbolone Acetate Another 19-nor steroid, short ester

FAQ

Common questions about NPP (Nandrolone Phenylpropionate)

Short answers, each backed by the sources below.

How does NPP differ from Deca?

Only the ester. In a study of healthy men one group received phenylpropionate and the others the same amount of decanoate. With phenylpropionate the nandrolone level peaked earlier and higher and own testosterone dropped fastest but also recovered fastest. With decanoate the suppression lasted longer.1

Is NPP approved?

Yes. The ChEMBL database lists nandrolone phenylpropionate as an approved drug with first approval in 1959. ClinicalTrials.gov, however, lists no trial with this ester (as of 26 October 2026). Everything here is the state of research, not a recommendation.98

How strongly does nandrolone bind to the receptor?

In a comparison study on rat and rabbit muscle and prostate nandrolone bound more strongly to the androgen receptor than testosterone. Only the research androgen methyltrienolone bound even more strongly. The pattern was similar in muscle and prostate.5

What did the trial before prostate surgery show?

54 men with benign prostate enlargement, mean age 70, received NPP or placebo once before surgery. 24 hours later their complaint score was 6.18 against 9.77 points, after 48 hours 4.48 against 5.55, which was no longer significant. There was no complication due to the compound. The authors call for larger trials.2

What do animal studies show?

Female rats received NPP at three levels for 10 days. Body protein rose by 9 percent at the lowest and the highest level and at the highest level body fat fell by 32 percent with unchanged weight. Muscle protein synthesis rose only at the two lower levels. The authors describe strongly dose-dependent effects.3

Does the Deca research also apply to NPP?

In part. Both esters release nandrolone but differ in the speed and height of the level. The large trials in dialysis, HIV or osteoporosis almost all used decanoate, in dialysis for example lean mass rose by 4.5 kg in 6 months against 1.9 kg on placebo. Such numbers cannot be transferred directly.14

Which side effects are known?

There are no frequencies from trials for NPP alone. Reviews of anabolic steroids describe suppressed own hormone production that can last for months after stopping, falling HDL cholesterol, rising blood pressure, acne and virilisation in women.76

Glossary

Terms explained briefly

Dotted words in the text open these explanations directly.

19-nor steroid
Steroid lacking the methyl group at carbon 19. Nandrolone and trenbolone belong to this group.
Androgen receptor
Protein inside the cell that androgens bind to. Genes are then read, for example for muscle building.
Decanoate ester
Long fatty acid chain, the ester of Deca. It releases nandrolone over a longer time.
Depot
The oil solution stays in the tissue after the injection and releases the compound over days.
Half-life
Time until half of a compound has been broken down or excreted.
Hormone axis (HPTA)
Hypothalamus, pituitary and testes together control the body's own testosterone production. Androgens from outside suppress this axis.
Phenylpropionate ester
Short acid chain on nandrolone. It makes it oil-soluble but releases it faster than long esters.
Pilot trial
Small preliminary trial that checks whether a larger trial is feasible and worthwhile.
Placebo
Dummy preparation without active substance. Comparing against it shows what is due to the substance itself.

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.

Tamoxifen (Nolvadex) SERM, core of PCT View Clomid (Clomifen) SERM, core of PCT View Enclomiphene (Androxal) SERM alternative View HCG testicular restart before PCT View Arimidex (Anastrozole) aromatase inhibitor, on-cycle View Aromasin (Exemestane) aromatase inhibitor, on-cycle View Cabergoline prolactin control for 19-nor View

Evidence

Sources

Show all 9 sourcesHide sources 7 Studies1 Trial registry1 Database checked 26 Oct 2026

Studies

  1. Nandrolone esters compared: ester, injection site and oil volume

    Minto et al., Journal of Pharmacology and Experimental Therapeutics, 1997

    DOI 10.1016/s0022-3565(24)36598-x PMID 9103484
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed (Titel, Datensatz ohne DOI)
  2. Pilot trial: NPP before prostate surgery

    Pourmand et al., The Aging Male, 2008

    DOI 10.1080/13685530802272857 PMID 18821287
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  3. Body composition and muscle protein in rats at three levels

    Choo et al., Annals of Nutrition and Metabolism, 1991

    DOI 10.1159/000177638 PMID 1952814
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  4. Nandrolone decanoate in dialysis, randomised against placebo

    Johansen et al., JAMA, 1999

    DOI 10.1001/jama.281.14.1275 PMID 10208142
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  5. Binding of anabolic steroids to the androgen receptor in muscle and prostate

    Saartok et al., Endocrinology, 1984

    DOI 10.1210/endo-114-6-2100 PMID 6539197
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  6. Review of the pharmacology of anabolic steroids

    Kicman, British Journal of Pharmacology, 2008

    DOI 10.1038/bjp.2008.165 PMID 18500378
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  7. Review: effects and side effects of anabolic steroids in athletes

    Hartgens und Kuipers, Sports Medicine, 2004

    DOI 10.2165/00007256-200434080-00003 PMID 15248788
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed

Trial registry

  1. Search on ClinicalTrials.gov

    ClinicalTrials.gov, U.S. National Library of Medicine

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2

Database

  1. Mechanism and approval in ChEMBL

    ChEMBL, EMBL-EBI (CHEMBL1200412)

    Checked 26 Oct 2026 via ChEMBL

In the shop

NPP (Nandrolone Phenylpropionate) in the catalog

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