TRT Dosage Calculator

How to Use This TRT Calculator

Pick the button that matches what you already know, then fill in your vial concentration and how often you inject.

1. I know my weekly dose. Enter the weekly milligrams from your prescription. The calculator splits it across your injection frequency and gives the volume per shot.
2. I know my dose per shot. Enter the milligrams you inject each time. The calculator gives the volume and shows what that adds up to per week.
3. I know the volume. Enter the mL or insulin units you draw and work backwards to milligrams per injection and per week. Useful for checking a dose against what is actually in the syringe.

All three give the same set of results: volume in mL, units on a U-100 insulin syringe, the nearest mark you can actually measure, and a 30-injection schedule you can download to your calendar.

Not on TRT yet? Open the second calculator underneath. Enter your age, height, weight and testosterone result and it returns your BMI, how your level compares to the reference range, and the starting dose range clinicians work from in mg, mL and syringe units. It shows the published range rather than a dose calculated for you — only a clinician can set that.

TRT Dose Formula: mg, mL and Syringe Units

Every testosterone volume calculation uses the same three numbers: your dose, the days between injections, and the concentration of your vial.

Working backwards from a volume simply reverses the last two steps:

Example 1: 140 mg per week, 200 mg/mL, twice weekly

140 ÷ 7 × 3.5 = 70 mg per injection. 70 ÷ 200 = 0.35 mL, which is 35 units on a U-100 insulin syringe.

Example 2: working backwards from 0.5 mL at 200 mg/mL

0.5 mL × 200 mg/mL = 100 mg per injection. Injected twice weekly, that is 100 ÷ 3.5 × 7 = 200 mg per week.

Example 3: 120 mg per week, 250 mg/mL, every other day

120 ÷ 7 × 2 = 34.3 mg per injection. 34.3 ÷ 250 = 0.14 mL, or about 14 units.

What Is a Typical Starting TRT Dose?

The Endocrine Society clinical practice guideline lists 75–100 mg per week, or 150–200 mg every two weeks, as typical intramuscular starting regimens for testosterone enanthate and testosterone cypionate. The FDA label for Depo-Testosterone gives a broader replacement range of 50 to 400 mg every two to four weeks, covering a wide spread of clinical situations. Xyosted, the subcutaneous enanthate auto-injector, starts at 75 mg once weekly and is adjusted in 25 mg steps.

These are starting points, not target doses. The guideline's aim is a testosterone level in the mid-normal range, reached by adjusting the dose after follow-up labs rather than by calculating it in advance.

What does not decide your dose

• Body weight. Injectable testosterone replacement is not prescribed per kilogram.
• Activity level. Training volume does not change a replacement dose.
• Age on its own. Age affects screening and monitoring decisions more than the starting amount.

What does decide it: a confirmed low morning testosterone result, your symptoms, your medical history, and how your levels respond once treatment starts.

Testosterone Reference Range: Where Does Your Result Sit?

The Endocrine Society guideline cites a harmonized reference range of 264 to 916 ng/dL for healthy non-obese men aged 19 to 39, based on the 2.5th and 97.5th percentiles. Individual laboratories publish their own ranges, so always compare your number to the range printed on your own report.

One low result is not a diagnosis. The guideline recommends confirming a low reading by measuring total testosterone on two separate mornings while fasting, because a substantial share of men with one low reading are in the normal range when retested. Read more about testosterone levels and the causes of low testosterone.

Testosterone Cypionate vs Enanthate: Concentrations and Half-Life

What concentration is on the vial

• Testosterone cypionate. Supplied in the US at 100 mg/mL (10 mL vials) and 200 mg/mL (1 mL and 10 mL vials), per the Depo-Testosterone label. Labelled for intramuscular injection.
• Testosterone enanthate. Generic enanthate injection is supplied in the US at 200 mg/mL in a 5 mL multiple-dose vial, also labelled for intramuscular injection. Higher concentrations such as 250 mg/mL appear on products sold outside the US, so check your own label rather than assuming.
• Xyosted. A testosterone enanthate auto-injector in 50 mg, 75 mg and 100 mg strengths, each delivering 0.5 mL, and the one testosterone product FDA approved for subcutaneous use. Its label restricts injection to the abdomen.

Half-life: what is actually documented

The FDA label for testosterone cypionate states that its half-life after intramuscular injection is approximately eight days. The label for testosterone enanthate gives no ester half-life in days at all; the figures you see quoted for enanthate, commonly in the region of 4.5 to 8 days, come from the pharmacokinetic literature rather than from the prescribing information.

You will also see a single figure of about 6.9 days quoted for both esters. That number traces back to a non-compartmental estimate from one study of supratherapeutic weekly cypionate dosing in healthy volunteers. The later population-pharmacokinetic reanalysis of that same dataset put the median at closer to 4 days. It was never measured for enanthate at all, so we do not publish it as a figure covering both esters.

For practical purposes the two esters are dosed on the same schedules and the volume math is identical. What changes your injection volume is the concentration on the vial, not the ester. See our TRT dosage guidelines for more.

How to Read an Insulin Syringe for TRT

• U-100 insulin syringes are marked so that 100 units = 1 mL and 1 unit = 0.01 mL.
• A 0.3 mL syringe holds 30 units, a 0.5 mL syringe holds 50 units, and a 1 mL syringe holds 100 units.
• The markings differ by size. A 1 mL U-100 syringe is normally graduated in 2-unit steps, so a calculated 37 units has to be rounded. The 0.3 mL and 0.5 mL sizes are available with half-unit markings and are far easier to read for small doses.
• At 200 mg/mL, every 10 units contains 20 mg of testosterone.
• Pick a syringe whose capacity is close to your dose. The calculator above shows the nearest mark you can actually measure for the size you would use.

Needle length, gauge and injection site depend on the route your prescription specifies. Cypionate and enanthate vials are labelled for intramuscular injection; subcutaneous injection from a vial is common in practice but is an off-label use of those products. Follow your prescriber's directions and our step-by-step guide on how to inject testosterone.

Important Safety Information

This calculator is an educational tool. It converts between a testosterone dose prescribed by a clinician and the volume to draw into a syringe, and it shows published starting ranges for context. It does not recommend a dose for you, and it is not medical advice.

• Testosterone is a prescription-only, Schedule III controlled substance in the United States. It should only be used under the supervision of a licensed clinician.
• Your dose is set by your clinician from your symptoms, your confirmed laboratory results and your medical history, then adjusted using follow-up bloodwork. It is not calculated from body weight, age or activity level.
• Always confirm the concentration printed on your own vial before drawing a dose. The same volume contains a different amount of testosterone at 100, 200 and 250 mg/mL.
• Testosterone cypionate and enanthate vials are labelled for intramuscular injection. Other routes, and any change to your dose or injection schedule, should be discussed with your prescriber first.
• If you think you have taken the wrong dose, contact your prescriber. In an emergency, call 911 or your local emergency number.

The Sanctuary Wellness Institute provides this page for general education. It does not create a clinician–patient relationship and is not a substitute for individual medical advice. Speak with one of our licensed clinicians about your own treatment.

References

1. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. PubMed — reference range of 264–916 ng/dL, the 75–100 mg/week starting regimen, two-morning confirmatory testing and the monitoring schedule.
2. DEPO-Testosterone (testosterone cypionate) injection, prescribing information. U.S. Food and Drug Administration. FDA label (PDF) — approximately eight-day half-life, 100 and 200 mg/mL presentations, 50–400 mg every two to four weeks, intramuscular route.
3. Testosterone enanthate injection, USP, prescribing information. DailyMed — 200 mg/mL in a 5 mL multiple-dose vial, intramuscular route, no ester half-life stated.
4. XYOSTED (testosterone enanthate) injection, for subcutaneous use, prescribing information. DailyMed — 50, 75 and 100 mg auto-injector strengths, subcutaneous abdominal administration, 75 mg weekly starting dose.
5. Bi Y, Perry PJ, Ellerby M, Murry DJ. Population Pharmacokinetic/Pharmacodynamic Modeling of Testosterone Cypionate. CPT Pharmacometrics Syst Pharmacol. 2018;7(4):259–268. PMC — context for the competing half-life estimates discussed above.
6. Anabolic steroids, including testosterone, listed under Schedule III. 21 CFR § 1308.13.

Last updated September 25, 2026. Information on this page is educational and is not a substitute for advice from your healthcare provider.