Last updated: June 2026
Masteron Dosage Calculator
Quick answer: A 300 mg/week dose over 3.5 shots from a 100 mg/mL vial is 0.857 mL (85.7 units) per shot, ≈ 252 mg active hormone/week. mL = (weekly mg ÷ shots) ÷ mg/mL.
Injectable ester — about 84% of each mg is Masteron; the calculator converts dose → mL, units and active mg. Aromatises: No. Liver-strain (17α-alkylated): No. Half-life: Propionate ≈ 2 days (drug monograph); Enanthate.
About this calculator
Masteron (drostanolone) is a DHT-derived injectable that does not aromatise. It comes as a fast propionate (≈84% active) and a slow enanthate (≈73% active). This calculator converts a dose into mL and U-100 units; pick the ester to set the active fraction. The propionate has a monograph half-life; the enanthate’s is not established, so its timeline is omitted.
Drostanolone is a 2α-methyl dihydrotestosterone derivative valued for its non-aromatising, "dry" profile. Propionate is usually 100 mg/mL and enanthate 200 mg/mL.
How the injection-volume maths works
Propionate is about 84% drostanolone (304.5 ÷ 360.5) and enanthate about 73% (304.5 ÷ 416.6), so the same labelled dose delivers different active milligrams. The calculator applies the factor for whichever ester you choose.
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 examples
Weekly dose: 300 mg · Concentration: 100 mg/mL · Injections/week: 3.5
85.71 mg/shot ÷ 100 = 0.857 mL (85.7 units) · active ≈ 252 mg/week
Weekly dose: 400 mg · Concentration: 200 mg/mL · Injections/week: 2
200 mg/shot ÷ 200 = 1 mL (100 units) · active ≈ 336 mg/week
Masteron dose chart
Common doses at 100 mg/mL, 2 injections/week (each row is the calculator’s arithmetic worked out):
| Weekly dose | mL/shot | Units | Active/week |
|---|---|---|---|
| 100 mg | 0.5 mL | 50 | 84 mg |
| 150 mg | 0.75 mL | 75 | 126 mg |
| 200 mg | 1 mL | 100 | 168 mg |
| 300 mg | 1.5 mL | 150 | 252 mg |
| 400 mg | 2 mL | 200 | 336 mg |
| 500 mg | 2.5 mL | 250 | 420 mg |
Half-life & clearance
Illustrative single-dose elimination by half-life (t½ ≈ 2 days). Each marker is one half-life; after ~5 the dose is essentially cleared. For an oil depot the real rise-and-fall is slower (absorption-limited release), so treat this as a timing reference, not a blood-level prediction.
Masteron propionate has a ~2-day depot (a drug-monograph figure, not a primary trial); the enanthate has no citable human half-life, so we show the conversion without a timeline for that ester.
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 Masteron that ester delivers — useful when comparing esters or switching concentrations. The half-life figure is a pharmacokinetic timing reference only.
Aromatisation, liver & monitoring
As a DHT derivative drostanolone does not aromatise, so it adds no estrogen of its own. It is not 17α-alkylated, so it is not directly hepatotoxic; its androgenic nature (hair, prostate) is the more typical concern.
Common mistakes
Mixing the two esters is the usual error — a 100 mg/mL propionate and a 200 mg/mL enanthate need different draw volumes for the same labelled dose. Set the ester first, then read the mL.
Masteron at a glance
| Property | Masteron |
|---|---|
| Form | Injectable (oil/suspension) |
| Active fraction | 0.84 (esterFactor) |
| Half-life | Propionate ≈ 2 days (drug monograph); Enanthate — not reliably established |
| Aromatises | No — a DHT derivative, not an aromatase substrate. |
| Liver (17α-alkylated) | No (not 17α-alkylated). |
| Approx. detection | ~3 weeks (propionate); longer for the enanthate. |
Frequently asked questions
Related guides
Other compounds
Other calculators
References
- PubChem — drostanolone (molecular weight), CID 6011
- PubChem — drostanolone propionate (molecular weight), CID 224004
- PubChem — drostanolone enanthate (molecular weight), CID 13014314
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol 2008;154(3):502–521
Every citation URL was verified to return HTTP 200. Citations are provided for transparency and education and 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 (1 mL = 100 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, both from PubChem). For orals it divides the daily dose by your doses-per-day and tablet strength to get tablets per dose. Half-life timing uses ke = ln2 ÷ t½ and the ~5-half-life rule of thumb for steady state and clearance. 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.