Question 1

How long does a 10 mL testosterone vial last?

Accepted Answer

A 10 mL vial of 200 mg/mL testosterone holds 2,000 mg total. At 100 mg/week it lasts about 20 weeks. At 150 mg/week, about 13 weeks. At 200 mg/week, about 10 weeks. Dead space from standard needles can shorten these numbers by 5–8% over the life of the vial. Use the calculator above for your exact dose, frequency, and needle type.

Question 2

What is syringe dead space and how much testosterone does it waste?

Accepted Answer

Dead space is the small amount of liquid trapped in the needle hub and syringe tip after injection. A standard needle wastes about 0.04 mL per injection. Over a 10 mL vial with 2 injections/week, that's roughly 5–8% of your medication. Low dead space (LDS) needles reduce this to nearly zero.

Question 3

Should I use low dead space needles for TRT?

Accepted Answer

If you inject frequently (2+ times per week), LDS needles can save you hundreds of mg over the life of a vial. They're especially worth it for expensive medications or smaller 1 mL vials. They cost slightly more but pay for themselves in saved medication.

Question 4

How many injections can I get from a 1 mL testosterone vial?

Accepted Answer

With a 200 mg/mL vial and 100 mg per injection (0.5 mL), you'll get 2 injections. With dead space, you might only get 1 full injection and a partial second. This is why many people prefer 10 mL multi-dose vials.

Question 5

Does testosterone expire once the vial is opened?

Accepted Answer

USP guidelines say multi-dose vials should be discarded 28 days after first puncture. In practice, many TRT clinics allow longer use if stored properly (room temperature, away from light). Check with your provider and watch for cloudiness or particles.

Question 6

How do I calculate my cost per week for TRT?

Accepted Answer

Divide the cost of your vial by the number of weeks it lasts. Enter your vial cost in the optional field above to see this automatically. Don't forget to factor in syringes, needles, and alcohol swabs.

Question 7

When should I reorder my vial?

Accepted Answer

Work out the day your current vial runs out (doses left × days between doses), then order a few days before that so the new one arrives in time. The calculator shows both dates above — pick a 3, 7, or 14-day buffer based on your typical shipping time.

Vial	Total testosterone	100 mg/wk	150 mg/wk	200 mg/wk	250 mg/wk
10 mL	2,000 mg	~20 wks	~13 wks	~10 wks	~8 wks
5 mL	1,000 mg	~10 wks	~6.5 wks	~5 wks	~4 wks
3 mL	600 mg	~6 wks	~4 wks	~3 wks	~2.5 wks

Testosterone Vial Calculator

How long does a testosterone vial last?

How to Use This Calculator

Enter your vial size

Enter concentration

Enter your weekly dose

Set injection frequency

Vial Longevity Q&A

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