TRT Injection Calculator
Convert your weekly mg, vial concentration, and injection frequency into exact insulin syringe units. Works for daily microdosing, every-other-day, twice-weekly, and weekly protocols.
TRT Dosage Calculator
Calculate your injection volume
Enter your weekly dose to calculate how much to draw per injection.
Common: Test Cyp/E (200mg/mL), Test Prop (100mg/mL)
Typical TRT range: 100-200mg per week
Per injection, draw
0.5 mL
= 50 units on a U-100 insulin syringe
(100mg per injection, 2x per week)
Now that you know your dose, never miss an injection.
Regimen tracks your testosterone cypionate protocol — 100mg twice a week. It reminds you when to inject, logs every dose, and shows your estimated blood levels between injections.
- Injection reminders on your schedule
- See testosterone level curves between doses
- Log injection sites to track rotation
Free for one compound. No trial, no paywall.
For educational and research purposes only. This calculator provides estimates based on standard formulas.
Always verify calculations with your healthcare provider before use. We assume no liability for dosing errors, adverse events, or outcomes resulting from use of this tool.
Worked example: 200 mg/week at 200 mg/mL
The 200 mg per week prescription at a 200 mg per mL vial concentration is the most common TRT setup in the US. The unit math falls cleanly across every standard injection frequency.
- Daily microdose (7x/week): 200 ÷ 7 = 28.6 mg per day. 28.6 ÷ 200 = 0.143 mL. About 14 units per day.
- Every other day (3.5x/week): approximately 57 mg per injection, which is 0.29 mL, or about 29 units.
- Twice weekly (2x/week): 100 mg per injection = 0.5 mL = 50 units.
- Weekly (1x/week): 200 mg = 1.0 mL = 100 units (fills the full barrel of a 100-unit insulin syringe).
The math generalizes to any concentration. If your vial is 100 mg per mL instead of 200, double the mL and unit numbers. If it's 250 mg per mL, multiply the mL by 0.8.
Why frequency matters more than total dose
With test cypionate's roughly 8-day half-life and test enanthate's 4.5-day half-life, your injection frequency directly drives how flat your weekly testosterone levels look. Weekly injection produces a noticeable peak-to-trough swing; twice-weekly compresses it; daily microdosing flattens it almost entirely. Flatter levels generally mean less estradiol conversion from peaks, less symptomatic variance, and easier hematocrit management.
Modern TRT clinical practice has moved toward twice-weekly minimum, with daily microdosing becoming common for users who want maximum stability. For the full walkthrough of daily and EOD protocols, including unit rounding for non-round divisions, see the microdosing TRT guide and the insulin syringe daily TRT dose guide.
Frequently asked questions
How many units for 200 mg/week TRT daily with a 200 mg/mL vial?
200 ÷ 7 ÷ 200 × 100 = approximately 14 units per day on a 100-unit insulin syringe. Round to 14 units. Exact math: 0.143 mL per day, which is 14.3 units.
What's the math for daily TRT microdosing?
Divide your weekly mg by 7 to get your daily mg. Divide that by your vial concentration in mg per mL to get mL. Multiply by 100 to get units on a 100-unit insulin syringe. The formula is: weekly_mg ÷ 7 ÷ concentration_mg_per_mL × 100 = daily units.
How do I split 200 mg/week into twice-weekly injections?
100 mg per injection. At 200 mg per mL that's 0.5 mL each, or 50 units on a 100-unit insulin syringe. Inject Monday and Thursday (or any pair of days roughly 3 to 4 days apart).
What concentration is standard for testosterone cypionate?
200 mg per mL is the most common in the US. Some pharmacies stock 100 mg/mL or 250 mg/mL. Always check your vial label and enter the actual concentration printed there.
Should I use a 100-unit or 50-unit insulin syringe?
For most TRT protocols, a 100-unit (1 mL) syringe is more flexible because it covers the full range from daily microdose draws up to weekly draws. A 50-unit (0.5 mL) syringe has finer unit markings and is preferred for smaller daily microdose protocols (under 25 units per draw) where precision matters.
How to use this calculator
Enter weekly mg
Your full prescribed weekly dose (e.g., 200 mg)
Enter vial concentration
Standard testosterone cypionate in the US is 200 mg/mL
Pick a frequency
Daily, every other day, twice weekly, or weekly
Read the units
Calculator returns exact units on a 100-unit insulin syringe
Log every TRT injection with the unit math built in
Regimen has the injection calculator built in and logs each shot with site rotation, dose, and reminders.
- Built-in dose calculators
- Smart injection reminders
- Symptom and lab correlation
- Private, secure health data
