Updated October 2, 2026

How to store reconstituted peptide vials

Once a powdered (lyophilized) vial is mixed, most labels say keep it in the fridge at 2–8°C (36–46°F), never frozen, and use it within a set number of days: 28 for Humatrope and Genotropin, 30 for Novarel. For any punctured multi-dose vial, USP and the CDC default to 28 days unless the label gives another date.

Powder and mixed vials are different products

A lyophilized vial is freeze-dried powder. Its label sets its storage before mixing. Once you add diluent, the clock and the temperature range change, and the mixed solution is usually the fragile one. The label's “after reconstitution” line is the one that counts once the needle goes in.

What labels say after mixing

These are FDA-approved products that ship as powder, so their labels give a tested rule. Most say fridge. Two say otherwise, which is the point: the specific label decides.

Product	Store the mixed vial	Use within
Humatrope	Fridge, 2–8°C (36–46°F)	Up to 28 days. Avoid freezing
Genotropin	Fridge, 2–8°C, between each use	Up to 28 days
Novarel (hCG)	Fridge, 2–8°C	Use within 30 days
Pregnyl (hCG)	Fridge, 2–8°C	Discard after 60 days. Do not freeze
Egrifta WR (tesamorelin)	Room temperature, 20–25°C	Discard 7 days after mixing
Glucagon kit (Fresenius)	—	Use immediately; discard what's left

The 28-day rule for punctured vials

USP <797>, the US standard for sterile preparations, says that once a multi-dose container is first entered or punctured, it “is not used for more than 28 days unless otherwise specified by the manufacturer on the labeling.” The CDC gives the same rule: date the vial when you first puncture it, and discard it within 28 days unless the manufacturer states another date. That date never runs past the vial's original expiration.

Travelling with mixed vials

2–8°C means fridge, not room. A mixed vial with a fridge label needs real cooling for the whole trip, not an insulated bag that drifts warm by afternoon.
Freezing is the other failure. Humatrope says avoid freezing the mixed cartridge and Pregnyl says do not freeze. Keep vials off ice packs and away from a mini-fridge's back wall.
Upright. A vial standing in a padded holder doesn't knock or roll.
Date it. Write the mixing date on the vial cap so the 28-day count survives the trip.

For the TSA side of it, see flying with injectable medication. For cooling options without a fridge, see the comparison.

Sources

This guide quotes manufacturer labels and government pages, linked above. Labels change, so the leaflet in your box and your pharmacist have the final word. VialCool sells an empty cooler, not medication.

Something out of date? Email support@vialcool.com.