How long does a 10 mL vial of testosterone last?
It comes down to two numbers on your label and prescription: the strength of the vial (mg per mL) and your weekly dose in mg. Multiply the strength by 10 mL to get the total in the vial, then divide by your weekly dose.
Note: this is general information, not medical advice. Your dose is set by your prescriber.
The quick table
Weeks a full 10 mL vial lasts, before allowing for waste:
| Weekly dose | 200 mg/mL vial (2,000 mg) | 250 mg/mL vial (2,500 mg) |
|---|---|---|
| 100 mg | 20 weeks | 25 weeks |
| 120 mg | 16.7 weeks | 20.8 weeks |
| 140 mg | 14.3 weeks | 17.9 weeks |
| 160 mg | 12.5 weeks | 15.6 weeks |
| 180 mg | 11.1 weeks | 13.9 weeks |
| 200 mg | 10 weeks | 12.5 weeks |
How you split the dose doesn't change how long the vial lasts: 140 mg a week is 140 mg a week whether it's one injection or seven.
Working it out for yours
- Total in the vial = strength × volume. 250 mg/mL × 10 mL = 2,500 mg.
- Weeks = total ÷ weekly dose. 2,500 ÷ 140 = 17.9 weeks.
- Volume per injection = dose ÷ strength. 70 mg ÷ 250 mg/mL = 0.28 mL, the 28 mark on a 1 mL insulin syringe.
The injection volume calculator does all three for any strength, dose and vial size.
Plan for a little less
In practice a vial gives a bit less than the maths says:
- A small amount stays in the needle and syringe each time you draw. With frequent small injections this adds up.
- You can't draw the very last drops out of the vial.
- A multi-dose vial has a use-by period once opened. Check your product's leaflet: if that comes first, it limits how long the vial lasts, not your dose.
Ordering the next vial a few weeks before the maths says you'll run out, allowing for delivery time, avoids a gap.
If your vial isn't what the label says
A lab test sometimes shows a vial is stronger or weaker than labelled. Then both the volume you draw and how long it lasts change. See what to do when a lab test shows your vial is off.
Keeping count
Enhanced Training Studio takes each logged dose off the open vial, so it always knows what's left, how many weeks your stock lasts and when to reorder, including sealed vials you haven't opened yet.
General information, not medical advice. Your prescriber sets your dose and schedule.
Track it without the spreadsheet
Enhanced Training Studio schedules every injection, shows what to draw, rotates your sites and estimates your levels. The protocol tracker is free, needs no account and keeps everything on your phone.
See the TRT tracker Levels calculator