What is Test/NPP Mix 150?
Test/NPP Mix 150 is a ready-made oil solution with 75mg testosterone propionate and 75mg nandrolone phenylpropionate (NPP) per ml, 150mg/ml in total. One vial holds 10 ml and needs no mixing. Both esters are short, so the blend is given often in small amounts.
It is the fast version of the classic testosterone and nandrolone pairing: levels build within days rather than weeks and drop just as quickly after stopping. In a research context that counts as an advantage when you want to react to side effects quickly.
This information is for research and educational purposes only. No medical advice.
Comparison
Testosterone and nandrolone, short or long
Which compounds each oil contains, as stated in the TPD lexicon. Tap a card to open its entry.
Simplified: the same compounds do not mean the same amount per ml. Every extra compound brings its own side effects.
How it works
Testosterone and nandrolone bind the androgen receptor in muscle and drive protein synthesis, nitrogen retention and recovery. Nandrolone is a 19-nor steroid, strongly anabolic and weaker on the androgenic side in tissue than testosterone. It acts noticeably on the progesterone receptor and can raise prolactin, while testosterone aromatizes to estradiol.
The ester only decides how fast the compound is released from the depot. Propionate has a half-life of about one day, phenylpropionate about two to three days. That is why two doses per week are not enough here; levels would swing too much.
Where it acts
One receptor, several organs
Tap a point or a card. Grey = effect seen in trials.
- Hypothalamus and pituitary
LH suppressed as long as testosterone was raised, one to two days with propionate6
Observed in trials - Testes
Sperm production suppressed: no sperm in 65 percent after 6 months, recovery within months after stopping7
Observed in trials - Blood
Haemoglobin and haematocrit rose with the testosterone dose, more in older men8
Observed in trials - Liver and blood lipids
HDL cholesterol fell by about 60 percent under several anabolic steroids at once3
Observed in trials - Heart and vessels
24-hour blood pressure higher (systolic 132 vs 124 mmHg), aorta stiffer4
Observed in trials - Skeletal muscle
Fat-free mass in dialysis patients +4.5 kg on nandrolone, +1.9 kg on placebo2
Observed in trials - Skin
Acne in 28 of 100 users, breast tissue growth in 199
Observed in trials
Targets in the ChEMBL database12
Compound CHEMBL1170: one recorded mechanism, agonist with direct binding to the human receptor.
- Gene
- AR
- UniProt
- P10275
- ChEMBL
- CHEMBL1871
- Action
- Agonist, direct binding
Use and 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
Injection
Intramuscular into the glute, thigh or shoulder, with a thick needle to draw up and a thin one (23G to 25G) to inject. Disinfect the stopper and the site first. With this many injections, rotate sites consistently.
Short esters like propionate sting noticeably more than long ones and irritate subcutaneous fat. Subcutaneous use is therefore a poor fit for this blend. If lumps or strong stinging appear, spread the volume over several sites.
What the research shows
A dose-response study shows that fat-free mass and strength rise with the testosterone dose while HDL falls in step (Bhasin, 2001). For nandrolone, randomized trials show gains in lean body mass and physical performance, for example in dialysis patients (Johansen, 1999). Those trials used the long decanoate ester; the active compound is the same as in NPP.
In strength athletes 200mg nandrolone per week on its own barely changed lipids, while several steroids at once lowered HDL sharply (Hartgens, 2004). Current and former users have higher blood pressure and a stiffer aorta on average (Rasmussen, 2018). There is no study of the fixed combination.
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.
Fat-free mass after 6 months2
Dialysis patients, weekly injection of nandrolone decanoate or placebo, gain in kg
Nandrolone with the long decanoate ester, the active substance is the same as in the phenylpropionate. The walking and stair test got faster (36.5 to 32.7 seconds) and slower on placebo (38.7 to 42.1). Grip strength did not change in either group.
How long levels stay raised after one injection6
Days (d) above the lower limit of the normal range, healthy men and men with hormone deficiency
LH stayed suppressed for as long as the level was raised. The enanthate dose was much higher than the two propionate doses, so the comparison shows ester and amount together.
Blood lipids under several anabolic steroids3
Change in percent, 19 strength athletes, self-chosen cycle over 8 or 14 weeks
Percentages calculated from the mean values in the abstract: HDL from 1.08 to 0.43 mmol/l, apo-A1 from 1.41 to 0.71 g/l, apo-B from 0.96 to 1.32 g/l, Lp(a) from 189 to 32 U/l. Six weeks after stopping the values had not yet recovered. Nandrolone decanoate alone did not change blood lipids in the second part of the study.
High blood pressure in users4
Share with systolic hypertension on 24-hour monitoring, strength athletes
Systolic 24-hour average 132 vs 124 mmHg. Aortic distensibility was 21 percent lower in current and in former users than in controls, so the aorta was stiffer.
Research status
Where the research stands
There is no study on the blend or on nandrolone phenylpropionate, testosterone propionate appears on the registry only as a nasal spray or cream. Shown are registered trials with nandrolone as decanoate, the same compound with a long ester, given by injection. As of 26 Oct 2026. 11
- Preclinical How anabolic steroids act in animals and cells (review)
- Phase 1 no registered trial
- Phase 2 4 trials on components, 2 completed, 1 stopped early
- Phase 3 no registered trial
- Approval both components, the blend itself without a study
Show all 4 phase 2 trials on a timelineHide timeline
NCT00242463 · 20 participants (planned), started Oct 2005, stopped early Oct 2007.
NCT02055456 · 20 participants, started Feb 2014, primary endpoint reached Feb 2017.
Registry entry ↗ · Results not yet in PubMed
HIP-SAP · NCT03545347 · 29 participants, started Sept 2018, primary endpoint reached May 2020. Tests several agents.
Registry entry ↗ · Results not yet in PubMed
SARKOPENIA · NCT05978206 · 168 participants (planned), started Aug 2023, primary endpoint planned Dec 2026. Tests several agents.
Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026, grey = stopped early.
Side effects
- Prolactin: the NPP share can raise prolactin, with effects on libido and erection. Prolactin belongs in the bloodwork.
- Lipids: HDL falls and LDL rises, more so together with testosterone than with nandrolone alone.
- Blood pressure: water retention and rising blood pressure are common. Measure regularly rather than guess.
- Sleep and mood: restless sleep, night sweats or mood swings are reported, often linked to prolactin and estradiol.
- Estrogen and blood count: testosterone aromatizes, gynecomastia is possible. Hematocrit rises.
- Hormone axis and skin: your own production is suppressed, plus acne and oily skin.
The upside of short esters: after stopping, side effects fade faster than with Test/Deca.
Tolerability
Frequency in the HAARLEM study
Out of 100 users, how many had the event. One cohort without a comparison group, participants chose compounds and amounts themselves.
| Event | All 100 users |
|---|---|
| At least one side effect9 | 100% |
| Lower libido after the cycle9 | 58% |
| Fluid retention during the cycle9 | 56% |
| Agitation during the cycle9 | 36% |
| Acne9 | 28% |
| Breast tissue growth (gynecomastia)9 | 19% |
Four participants had a serious event: heart failure, pancreatitis, suicidal thoughts and a flare of ulcerative colitis. One year after the start the observed effects were back at baseline. Prolactin effects were not reported separately.9
Storage
Store at room temperature, in the dark and in the original packaging, out of reach of children. Do not put it in the fridge, because cold makes the compounds crystallize out of the oil. If you see crystals, warm the vial in your hand or in warm water and swirl until the solution is clear again. Disinfect the stopper before every draw.
