Last updated: June 2026

NPP Dosage Calculator

Q: How do I calculate my NPP dose?

Divide your weekly dose by the number of injections, then by the vial concentration: mL = (weekly mg ÷ shots) ÷ mg/mL, and × 100 for U-100 syringe units. The calculator above does this instantly.

Q: What is the active-hormone amount for NPP?

NPP is an ester, so only part of each milligram is hormone. Its esterFactor is 0.67 (parent MW 274.4 ÷ ester MW 406.6), so a 100 mg dose delivers about 67 mg of the parent hormone.

Q: Does it aromatise or stress the liver?

Aromatises: Partial / weak — aromatises far less than testosterone; mainly progestogenic. 17α-alkylated (liver strain): No (not 17α-alkylated).

Q: Is this medical advice?

No. This is an educational arithmetic tool. It converts the numbers you enter, stores nothing, and does not recommend any dose, cycle, or protocol. Anabolic steroid use carries real health risks — consult a qualified clinician.

Quick answer: A 100 mg/week dose over 3.5 shots from a 100 mg/mL vial is 0.286 mL (29 units) per shot, ≈ 67 mg active hormone/week. mL = (weekly mg ÷ shots) ÷ mg/mL.

About this calculator

NPP is the short-ester form of nandrolone (19-nortestosterone). About 67% of each milligram is active nandrolone. This calculator converts your weekly dose into draw volume and syringe units, and shows the depot half-life that drives its more-frequent injection schedule versus long-ester Deca. esterFactor = 274.4 ÷ 406.6 = 0.67 (active NPP fraction).

How to use this calculator

Enter your weekly dose, the concentration printed on your vial (mg/mL), and how many injections per week. The result updates instantly with the mL to draw, the U-100 syringe units, and the active-hormone milligrams delivered.

Worked example

Worked example — injectable

Weekly dose: 100 mg · Concentration: 100 mg/mL · Injections/week: 3.5

28.6 mg/shot ÷ 100 = 0.286 mL (29 units) · active hormone ≈ 67 mg/week

How to interpret your result

The result is the volume to draw per injection and its mark on a U-100 syringe. The active-hormone figure shows how much actual NPP that ester delivers — useful when comparing esters. The half-life figure is a pharmacokinetic timing reference only. For oil depots it is the absorption-limited release of the ester, not the cleared parent hormone.

NPP at a glance

Property	NPP
Form	Injectable (oil/suspension)
Active fraction	0.67 (esterFactor)
Half-life	≈ 2.7 days (65 h) oil-depot; free nandrolone clears in < 4.3 h
Aromatises	Partial / weak — aromatises far less than testosterone; mainly progestogenic.
Liver (17α-alkylated)	No (not 17α-alkylated).
Approx. detection	Very long — the 19-norandrosterone marker is detectable for months.

Frequently asked questions

How do I calculate my NPP dose?

Divide your weekly dose by the number of injections, then by the vial concentration: mL = (weekly mg ÷ shots) ÷ mg/mL, and × 100 for U-100 syringe units. The calculator above does this instantly.

What is the active-hormone amount for NPP?

NPP is an ester, so only part of each milligram is hormone. Its esterFactor is 0.67 (parent MW 274.4 ÷ ester MW 406.6), so a 100 mg dose delivers about 67 mg of the parent hormone.

What is the half-life of NPP?

≈ 2.7 days (65 h) oil-depot; free nandrolone clears in < 4.3 h.

Does it aromatise or stress the liver?

Aromatises: Partial / weak — aromatises far less than testosterone; mainly progestogenic. 17α-alkylated (liver strain): No (not 17α-alkylated).

Is this medical advice?

No. This is an educational arithmetic tool. It converts the numbers you enter, stores nothing, and does not recommend any dose, cycle, or protocol. Anabolic steroid use carries real health risks — consult a qualified clinician.

Choose a compound

Testosterone Cypionate Anavar (Oxandrolone) Trenbolone Dianabol (Methandrostenolone) NPP (Nandrolone Phenylpropionate) Turinabol (Tbol) Deca (Nandrolone Decanoate) Winstrol (Stanozolol) Equipoise (Boldenone Undecylenate)

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References

Citations are provided for transparency and education. They do not imply the cited authors or bodies endorse this tool. Anabolic steroid use carries real health risks — always consult a qualified clinician.

How this is calculated

For injectables the calculator divides your weekly dose by the number of injections, then by the vial concentration, to get the mL per shot — and multiplies by 100 for U-100 syringe units. The active-hormone milligrams are the dose multiplied by the esterFactor (the parent hormone's molecular weight divided by the full ester's molecular weight). For orals it divides the daily dose by your doses-per-day and tablet strength to get tablets per dose. It is arithmetic only — nothing you enter is stored or sent anywhere, and the result is not medical advice or an endorsement of anabolic steroid use.