Searches for retatrutide in units come in two shapes: how many units a trial amount is, and how many milligrams a unit reading holds. The second has no table anywhere else on this site, and it is the one people reach after a syringe is already filled. Both have the same answer: a unit is a volume, 0.01 mL on a U-100 syringe, so its milligram content is set by the concentration of the vial and by nothing else. This page gives the reverse table first, the forward conversion second, and the size of a one-unit misread at each concentration. It reports arithmetic; it recommends no amount.
The trial ladders themselves, with their registry numbers, are on the retatrutide dosing schedule. The milligram doses by vial size and water volume are on the retatrutide dosage page, and the water side of the arithmetic on the retatrutide reconstitution page. The compound itself is covered in Medibact's Retatrutide guide.
The status, before any number
Retatrutide has no approved label anywhere. Its four phase 3 TRIUMPH registry entries (NCT05929066, NCT05929079, NCT05882045, NCT05931367) were listed as completed with no posted results when read on 2026-10-15. The milligram amounts that circulate come from two phase 2 trials (0.5, 1, 2, 4, 8 and 12 mg once weekly) and from Eli Lilly's 2026 releases on phase 3 (steps of 2, 4, 6 and 9 mg to an assigned 4, 9 or 12 mg). None of those sources states a unit count. Every unit figure below is a conversion of a milligram figure, and a conversion is only as good as the concentration it uses.
The formula
units = mg ÷ concentration (mg/mL) × 100, and in reverse mg = units ÷ 100 × concentration. The concentration is the vial's labelled milligrams divided by the millilitres of water added. Research-market retatrutide is labelled 5, 10 and 20 mg, so 1, 2 or 3 mL of water produces 1.67 to 20 mg/mL. The mg to units page sets out the general method and the tenfold slips it guards against.
Units to milligrams
Each row is a unit reading on a U-100 syringe. Each column is a concentration a research vial produces: 2.5 mg/mL (5 mg in 2 mL), 3.33 mg/mL (10 mg in 3 mL), 5 mg/mL (5 mg in 1 mL, or 10 mg in 2 mL), 10 mg/mL (10 mg in 1 mL, or 20 mg in 2 mL) and 20 mg/mL (20 mg in 1 mL).
| Units (mL) | 2.5 mg/mL | 3.33 mg/mL | 5 mg/mL | 10 mg/mL | 20 mg/mL |
|---|---|---|---|---|---|
| 5 (0.05 mL) | 0.13 mg | 0.17 mg | 0.25 mg | 0.5 mg | 1 mg |
| 10 (0.10 mL) | 0.25 | 0.33 | 0.5 | 1 | 2 |
| 20 (0.20 mL) | 0.5 | 0.67 | 1 | 2 | 4 |
| 25 (0.25 mL) | 0.63 | 0.83 | 1.25 | 2.5 | 5 |
| 30 (0.30 mL) | 0.75 | 1 | 1.5 | 3 | 6 |
| 40 (0.40 mL) | 1 | 1.33 | 2 | 4 | 8 |
| 50 (0.50 mL) | 1.25 | 1.67 | 2.5 | 5 | 10 |
| 60 (0.60 mL) | 1.5 | 2 | 3 | 6 | 12 |
| 80 (0.80 mL) | 2 | 2.67 | 4 | 8 | 16 |
| 100 (1.00 mL) | 2.5 | 3.33 | 5 | 10 | 20 |
Every row spans an eightfold range. "Forty units" is 1 mg in a 5 mg vial mixed with 2 mL and 8 mg in a 20 mg vial mixed with 1 mL. A unit reading without the vial and the water volume beside it is not a dose record of any kind, which is the whole content of the question "is 40 units of retatrutide a lot".
Every trial amount as units
The forward direction, kept to the amounts the trials name and the four concentrations that put every step on a single 1 mL syringe at least once.
| Trial amount | Where it appears | 2.5 mg/mL | 5 mg/mL | 10 mg/mL | 20 mg/mL |
|---|---|---|---|---|---|
| 0.5 mg | phase 2 fixed arm (type 2 diabetes) | 20 | 10 | 5 | 2.5 |
| 2 mg | first step, phase 2 and phase 3 | 80 | 40 | 20 | 10 |
| 4 mg | step and maintenance | 160 | 80 | 40 | 20 |
| 6 mg | phase 3 step | 240 | 120 | 60 | 30 |
| 9 mg | phase 3 step and maintenance | 360 | 180 | 90 | 45 |
| 12 mg | maintenance | 480 | 240 | 120 | 60 |
Cells over 100 do not fit one U-100 syringe. Read as sentences: at 10 mg/mL the phase 3 ladder of 2, 4, 6, 9 and 12 mg is 20, 40, 60, 90 and 120 units; at 20 mg/mL it is 10, 20, 30, 45 and 60. The full grid by vial size and water volume, including 1, 8 mg and the 3 mL rows, is on the retatrutide dosage page; the retatrutide calculator works any vial and volume entered.
What one unit holds, and what a misread costs
The concentration that makes the volume small also makes each mark carry more drug. One unit holds:
| Concentration | mg in 1 unit | 1 unit as a share of 2 mg | 1 unit as a share of 12 mg |
|---|---|---|---|
| 2.5 mg/mL | 0.025 mg | 1.25% | 0.21% |
| 5 mg/mL | 0.05 mg | 2.5% | 0.42% |
| 10 mg/mL | 0.1 mg | 5% | 0.83% |
| 20 mg/mL | 0.2 mg | 10% | 1.67% |
The barrel adds its own resolution. The 1 mL syringe in BD's FDA clearance (K190054, as recorded on this site's insulin syringe units page) is marked in 2-unit steps, so a reading halfway between marks is a one-unit uncertainty by construction; the 0.3 mL barrel is marked in 1- or half-unit steps. At 20 mg/mL, a 2 mg amount is 10 units, and one unit either way is a tenth of it. At 5 mg/mL the same 2 mg is 40 units and one unit is a fortieth. That trade-off, smaller volume against coarser marks, is the arithmetic behind the dilution choices in the reconstitution tables; it is not a recommendation of either.
What this page does not establish
No label, regulator or posted trial result gives a retatrutide amount in units, and none gives an amount to use; every figure here is a conversion of a published milligram figure at a stated concentration. A research vial's concentration is only as accurate as its labelled content, and no source read for this page measured how closely research vials match their labels. Nothing here is a suggested amount; decisions about amounts belong with a prescriber.
Sources and dates
Opened 2026-10-15: the ClinicalTrials.gov v2 records for NCT05929066, NCT05929079, NCT05882045 and NCT05931367 (overall status, results flag, last update). The phase 2 arm sequences (NCT04881760, NCT04867785), the Lilly releases of 2026-05-21 and 2026-07-23 and the papers behind them are as read and cited on this site's retatrutide dosing schedule (2026-10-14). Syringe barrel markings from BD's 510(k) K190054 as recorded on this site's insulin syringe page (read 2026-09-18). All unit and milligram arithmetic by this site. Corrections go to the contact page.