TRT Calculators
Last updated: June 2026
Daily TRT Microdose: Units Chart for 10-30mg Per Day
This is a reference chart that converts common daily testosterone microdoses, from 10 mg to 30 mg per day, into insulin-syringe units at a concentration of 200 mg/mL. It covers only the measurement arithmetic, not what dose anyone should take.
The daily testosterone microdose units chart at 200 mg/mL
This daily testosterone microdose units chart assumes the most common compounded and commercial concentration, 200 mg/mL, drawn on a U-100 insulin syringe. On a U-100 syringe, 1 mL is marked as 100 units, so 0.01 mL equals 1 unit. The chart shows each daily dose, the volume it occupies, the units to draw, and the weekly total it adds up to.
| Dose per day (mg) | Volume (mL) | Units (U-100) | Weekly total (mg) |
|---|---|---|---|
| 10 mg | 0.05 mL | 5 units | 70 mg |
| 12.5 mg | 0.0625 mL | 6.25 units | 87.5 mg |
| 15 mg | 0.075 mL | 7.5 units | 105 mg |
| 17.5 mg | 0.0875 mL | 8.75 units | 122.5 mg |
| 20 mg | 0.10 mL | 10 units | 140 mg |
| 25 mg | 0.125 mL | 12.5 units | 175 mg |
| 30 mg | 0.15 mL | 15 units | 210 mg |
The figures are pure unit conversions, not a recommendation. Your prescribed dose, ester, and concentration come from your prescriber. To change any input, use the TRT Microdosing Calculator.
How the math works
Two steps convert a dose in milligrams into syringe units. First, divide the dose by the concentration to get the volume in millilitres. Second, multiply that volume by 100 to get U-100 units.
- Volume (mL) = dose (mg) / concentration (mg/mL)
- Units = volume (mL) × 100
At a fixed concentration of 200 mg/mL these collapse into a single shortcut: units = mg / 2. Every 2 mg of testosterone at 200 mg/mL equals 1 unit on a U-100 syringe. That is why 20 mg lands exactly on the 10-unit mark and 30 mg on the 15-unit mark.
Example
Dose: 15 mg per day. Concentration: 200 mg/mL. Volume = 15 / 200 = 0.075 mL. Units = 0.075 × 100 = 7.5 units. Using the shortcut: 15 / 2 = 7.5 units. Both methods agree.
If you are new to the underlying ideas, the guides on how mg/mL works and syringe units explained walk through each step slowly.
Why the concentration changes the units
The same milligram dose draws to a different number of units at a different concentration. The chart above is built for 200 mg/mL. If your vial is a different strength, the units move.
| Daily dose | At 100 mg/mL | At 200 mg/mL | At 250 mg/mL |
|---|---|---|---|
| 10 mg | 10 units | 5 units | 4 units |
| 20 mg | 20 units | 10 units | 8 units |
| 30 mg | 30 units | 15 units | 12 units |
A higher concentration packs more milligrams into each millilitre, so the same dose occupies fewer units. Always confirm the concentration printed on your own vial before reading any chart. The guide why vial strength changes the dose explains this in more detail.
Reading half-unit doses on a U-100 syringe
Several daily microdoses land on a half-unit: 12.5 mg is 6.25 units, 15 mg is 7.5 units, 17.5 mg is 8.75 units, 25 mg is 12.5 units. A standard U-100 syringe is marked in whole units, so quarter-unit values like 6.25 and 8.75 fall between marks and are hard to measure precisely.
- Doses that resolve to whole units (10 mg = 5 units, 20 mg = 10 units, 30 mg = 15 units) are the easiest to draw accurately.
- Half-unit values (15 mg = 7.5 units, 25 mg = 12.5 units) sit on a readable midpoint between two marks.
- Quarter-unit values (12.5 mg, 17.5 mg) are the hardest to read and most prone to measurement error at small volumes.
Example
Dose: 12.5 mg per day at 200 mg/mL. Volume = 12.5 / 200 = 0.0625 mL, which is 6.25 units. On a whole-unit U-100 syringe this falls a quarter of the way between the 6 and 7 marks. A 0.3 mL (30-unit) syringe spreads the same volume across more visible marks and is easier to read at this scale, as covered in 0.3 mL vs 0.5 mL vs 1 mL syringes.
Daily microdosing versus EOD and longer intervals
Daily dosing splits a weekly total into seven equal injections, which is why each daily draw is small. The weekly total column in the main chart shows the trade-off: a 20 mg daily dose is 140 mg per week, the same weekly amount whether it is split daily, every other day, or twice weekly. Only the per-injection volume changes.
The clinical rationale for splitting frequency relates to the half-life of the ester. Shorter esters such as testosterone propionate have a much shorter half-life than longer esters such as cypionate or enanthate, which influences how often some protocols inject. Frequency choice is a medical decision, not a measurement one, and there is no solid evidence that any one schedule suits everyone; it is unsafe to change without medical supervision. The conceptual side is covered in why injection frequency matters and testosterone esters explained.
Common measurement mistakes at small volumes
Small daily volumes magnify reading errors. A few practical points that follow directly from the arithmetic:
- Confirm the concentration first. Reading a 200 mg/mL chart while holding a 100 mg/mL vial doubles the dose. The concentration is the single most important number.
- Account for dead space. Liquid trapped in the needle hub is not delivered. At microdose volumes this is a larger fraction of the draw than at higher volumes, as explained in what is dead space in a syringe.
- Do not confuse units with millilitres. On a U-100 syringe, 10 units is 0.10 mL, not 10 mL. The guide why 10 units does not always mean the same dose shows how the same unit mark maps to different milligram doses at different strengths.
FAQs
How many units is 20 mg of testosterone per day at 200 mg/mL?
20 mg at 200 mg/mL is 0.10 mL, which is 10 units on a U-100 insulin syringe. The shortcut at 200 mg/mL is units = mg / 2, so 20 / 2 = 10 units.
What is the formula for converting a daily testosterone dose to syringe units?
Divide the dose in milligrams by the concentration in mg/mL to get volume in millilitres, then multiply by 100 for U-100 units. At 200 mg/mL this simplifies to units = mg divided by 2.
Why is my daily draw such a small volume?
Daily dosing splits the weekly total across seven injections, so each draw is roughly one seventh of a less-frequent dose. A 20 mg daily dose is only 0.10 mL, while the same 140 mg weekly total injected twice weekly would be 0.35 mL per shot.
Does this chart tell me what dose to take?
No. It is a unit-conversion reference only. Your dose, concentration, ester, and injection frequency are medical decisions set by your prescriber. This page converts a known dose into syringe units and nothing more.
What if my vial is not 200 mg/mL?
The units change. At 100 mg/mL the same dose needs twice as many units; at 250 mg/mL it needs fewer. Always read the concentration on your own vial and recalculate, or enter it into the TRT Microdosing Calculator.
Read next
Trt Every 35 Days Calculator GuideSources
- 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.ncbi.nlm.nih.gov/29562364.
- DailyMed. DEPO-Testosterone (testosterone cypionate) injection, solution drug label. U.S. National Library of Medicine. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cfbb53d4-b868-4a28-8436-f9112eb01c39.
- MedlinePlus. Giving an insulin injection. U.S. National Library of Medicine Medical Encyclopedia. medlineplus.gov/ency/patientinstructions/000660.htm.
- Behre HM, Abshagen K, Oettel M, Hubler D, Nieschlag E. Intramuscular injection of testosterone undecanoate for the treatment of male hypogonadism: phase I studies. Eur J Endocrinol. 1999;140(5):414-419. pubmed.ncbi.nlm.nih.gov/10229906.
This guide is for general educational purposes only and does not constitute medical advice. Always follow your prescriber's specific instructions.