Nandrolone Phenylpropionate (NPP): Status and mg to mL
App Library Tools Pricing Download
[Anabolic · Compound guide]

Nandrolone Phenylpropionate: US status and mg to mL math

Vial strengths · mg to mL · Units chart · Half-life notes

What is nandrolone phenylpropionate?

Nandrolone phenylpropionate (NPP, also spelled phenpropionate) is the anabolic steroid nandrolone attached to a shorter phenylpropionate ester and dissolved in oil for injection into muscle. It was sold in the US as Durabolin, but that approval was withdrawn in 2018.

Also known as: NPP, Durabolin, nandrolone phenpropionate.

Common strengths

Durabolin came as 25 mg/mL and 50 mg/mL injections, and Drugs@FDA lists it and every US generic as discontinued. Check the strength printed on your vial; the math below uses 50 mg/mL only as an example. It is already a liquid, so there is nothing to mix.

Worked example: mg to mL and syringe units

Nandrolone phenylpropionate is already a solution, so there is no mixing. The only math is turning an amount in mg into a volume. Here it is at 50 mg/mL for 25 mg.

  1. Volume to draw. 25 mg ÷ 50 mg/mL = 0.5 mL
  2. On a U-100 syringe. 0.5 mL × 100 = 50 units
The amount here is an example to show the math, not a recommendation. How much to take is a decision for you and your prescriber. Check the strength printed on your vial; the same amount is a different volume at a different strength.

Volume chart at 50 mg/mL

Amounts are examples for the conversion, not doses.
AmountVolumeU-100 syringe
12.5 mg0.25 mL25 units
25 mg0.5 mL50 units
37.5 mg0.75 mL75 units
50 mg1 mL100 units

US status and how it compares with the decanoate

FDA withdrew approval of Durabolin (nandrolone phenpropionate injection, NDA 011891) in September 2018 after the holder said it was no longer marketed. Drugs@FDA lists Durabolin and the generic nandrolone phenpropionate injections as discontinued, so there is no NPP product approved for people in the US today.

Anabolic steroids are Schedule III controlled substances in the US, and this one is named in the federal list (21 CFR 1308.13(f)). Having it without a valid prescription is illegal. (Nandrolone and its esters are listed.) It is on the World Anti-Doping Agency (WADA) Prohibited List as an anabolic agent, banned in and out of competition.

In a study of healthy men given a single 100 mg injection of either nandrolone ester (Minto 1997), the phenylpropionate gave higher and earlier peak nandrolone levels than the decanoate, and suppressed the body's own testosterone faster but for a shorter time. For the label warnings that apply to nandrolone, see the nandrolone decanoate page.

Nandrolone phenylpropionate half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

The study we found that compared the two esters in men (Minto 1997) reports that the phenylpropionate peaks higher and earlier than the decanoate, but its summary gives no half-life or time to peak in hours, so we do not list one.

How to track nandrolone phenylpropionate in Dose Track

  1. Add nandrolone phenylpropionate as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Save the vial strength (for example 50 mg/mL). Every amount you log then shows in mL and syringe units.
  3. Log each shot. The app subtracts it from the vial, shows what is left, and warns you before you run out.
  4. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  5. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

Nandrolone DecanoateDeca-Durabolin, Deca · half-life about 8 days Testosterone PropionateTest P · half-life about 20 hours TrenboloneTrenbolone acetate, Trenbolone enanthate Trestolone (MENT)MENT, 7α-methyl-19-nortestosterone

Frequently asked questions

How many mL is 25 mg of nandrolone phenylpropionate?+
Divide the amount by the strength on the vial. At 50 mg/mL, 25 mg is 0.5 mL. At a different strength the volume changes, so always check the label. The amount is only an example for the math, not a recommendation.
How many units on an insulin syringe is 25 mg of nandrolone phenylpropionate?+
On a U-100 insulin syringe, 1 mL is 100 units. At 50 mg/mL, 25 mg is 0.5 mL, which is 50 units. Multiply the mL by 100 to get units.
What is the half-life of nandrolone phenylpropionate?+
The study we found that compared the two esters in men (Minto 1997) reports that the phenylpropionate peaks higher and earlier than the decanoate, but its summary gives no half-life or time to peak in hours, so we do not list one.
What is the difference between NPP and nandrolone decanoate?+
Both are nandrolone. NPP has a shorter phenylpropionate ester, and in a study in men (Minto 1997) it reached higher, earlier peak levels than the decanoate and its effect on testosterone was shorter. Dose Track has nandrolone decanoate built in.
Can I track nandrolone phenylpropionate in Dose Track?+
Yes. Nandrolone phenylpropionate is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each shot next to your other compounds, save the vial strength so every amount shows in mL and syringe units, see how much is left in the vial, and get reminders. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Minto CF, et al. Pharmacokinetics and pharmacodynamics of nandrolone esters in oil vehicle: effects of ester, injection site and injection volume. J Pharmacol Exp Ther. 1997;281(1):93-102.
  2. Drugs@FDA: Durabolin (nandrolone phenpropionate) injection, NDA 011891, marketing status.
  3. FDA. Merck Sharp & Dohme Corporation, et al.; withdrawal of approval of four new drug applications (includes Durabolin, NDA 011891). Federal Register, August 8, 2018.
  4. 21 CFR 1308.13(f): Schedule III anabolic steroids. eCFR, October 2026.
  5. World Anti-Doping Agency. 2026 Prohibited List (S0 non-approved substances; S1 anabolic agents; S4.1 aromatase inhibitors; S4.4.1 metabolic modulators).

All compound guides · Reconstitution calculator · Supported medications