Why do vendors sell different vial sizes (10mg vs 30mg) for the same peptide?

Vial size is a packaging decision, not a property of the peptide. The same compound at 10 mg and 30 mg is the same molecule in a different quantity.

Why vendors offer several

• Different suppliers standardise on different fill volumes.
• Larger vials usually cost less per milligram, so they serve buyers optimising on cost.
• Smaller vials suit shorter protocols and reduce how long a reconstituted vial must remain stable.

Bigger is not automatically better value

Price per mg is the right comparison — vial price divided by the milligrams inside — but it is not the whole calculation. Once reconstituted, a vial is on a stability clock of roughly 14–30 days refrigerated. A 30 mg vial that outlasts that window at your intended dose is not cheaper in practice; the unused portion is waste.

The useful question is therefore how much you will actually use before the reconstituted material stops being viable, and then which vial size gets you there at the lowest cost per mg.

Worked comparison

A 10 mg vial at $60 is $6.00/mg. A 30 mg vial at $150 is $5.00/mg — 17% cheaper per milligram, and genuinely better value only if the full 30 mg gets used.

The vendor comparison lists price per mg across suppliers so sizes can be compared directly, and the calculator works out doses per vial. See also how price per mg is calculated. Research use only. Not medical advice.