How many units is 0.5 mg of semaglutide?

It depends on exactly one thing: the concentration printed on your vial. Here it is at the 4 strengths compounded semaglutide usually comes in, and drawn on the barrel.

At 1 mg/mL, 0.5 mg is 50 units (0.5 mL). At 2.5 mg/mL, 0.5 mg is 20 units (0.2 mL). At 5 mg/mL, 0.5 mg is 10 units (0.1 mL). At 10 mg/mL, 0.5 mg is 5 units (0.05 mL).

0.5 mg of semaglutide, by vial concentration. U-100 insulin syringe.
Vial says	Which is	mL	Units	Syringe
1 mg / 1 mL 2 mg / 2 mL 5 mg / 5 mL	1 mg/mL	0.5	50	50-unit
2.5 mg / 1 mL 5 mg / 2 mL 10 mg / 4 mL	2.5 mg/mL	0.2	20	30-unit
5 mg / 1 mL 10 mg / 2 mL	5 mg/mL	0.1	10	30-unit
10 mg / 1 mL 20 mg / 2 mL	10 mg/mL	0.05	5	30-unit

What that looks like on the barrel

1 mg/mL → 50 units on a 50-unit syringe

2.5 mg/mL → 20 units on a 30-unit syringe

5 mg/mL → 10 units on a 30-unit syringe

10 mg/mL → 5 units on a 30-unit syringe

About this dose

Weeks 5–8. Weeks five to eight, the first dose that does real work, and where a fair number of people stay. At 2.5 mg/mL it's 20 units — the number a lot of people remember. At 10 mg/mL it's still only 5 units; if that's what you've been sent, it's worth asking for a weaker vial.

Check it yourself

The whole sum is units = dose ÷ concentration × 100. For this dose at 1 mg/mL: 0.5 ÷ 1 × 100 = 50. If your vial isn't marked in mg/mL, the concentration is the vial's total milligrams divided by the water that went in — a 2 mg vial with 2 mL of water is 1 mg/mL.

Not one of those concentrations?

Semaglutide vial → unitsU-100 syringe

Vial strength mg

Water you added mL

Your dose mg

Syringe

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Fill in all three boxes.

Common setups:

← 0.25 mg 1 mg →

Other doses: 0.25 mg · 1 mg · 1.7 mg · 2.4 mg. The whole ladder, with every dose at every strength: the semaglutide chart. Going the other way — you drew a number of units and want the milligrams — is here. And if the vial isn't semaglutide at all, mg to units works for anything.