When a tesamorelin order arrives, check that each vial is intact and sealed, that the lyophilised material looks like a dry white cake or powder, and then put the sealed vials in the fridge or freezer, in their box. Lyophilised tesamorelin does not need an ice pack in transit, and it does not need to be mixed on arrival.
Our tesamorelin is supplied as 10 mg lyophilised vials and ships within Canada by Canada Post Xpresspost. The few minutes spent on these checks protect the material for the months it may sit in storage before use.
Check the vial and seal
- Glass intact. No cracks, chips or star fractures, particularly around the base and the neck.
- Cap and crimp in place. The flip-off cap should be seated, and the aluminium crimp tight around the rubber stopper with no gap or spinning.
- Stopper undisturbed. The rubber should sit flush and unpunctured.
- Box dry. The packaging should be free of moisture inside.
A sealed vial matters more for tesamorelin than for most peptides because water is what drives its degradation. Asparagine 8 deamidates and aspartate 3 isomerises only when water is present (Bongers, International Journal of Peptide and Protein Research, 1992), so an intact seal keeps the cake in the dry state where those reactions effectively stop.
What the cake should look like
Lyophilised tesamorelin is a white to off-white solid. In the vial it usually appears as one of the following, all of which are normal:
- A firm, slightly porous disc or plug at the bottom of the vial.
- A cake that has shrunk away from the glass, or cracked into a few pieces.
- A loose powder or flakes, where the cake broke up in transit or was dislodged from the base.
- A thin film on the walls or under the stopper after the vial has been tipped.
The amount looks small. At a molecular weight of about 5,136, tesamorelin is one of the heavier single peptides in the catalogue, and 10 mg of it is a modest volume of solid. A cake that has moved or broken is not a concern; lyophilised material is fragile, and the mass in the vial is unchanged.
What would be worth contacting us about: a cake that looks wet, glassy, sticky or collapsed into a syrup-like layer, visible liquid in an unopened vial, or any yellow or brown colour. Each of these suggests moisture got in.
Why there is no ice pack
The reactions that limit tesamorelin’s life all need water. Deamidation at asparagine 8 runs through a cyclic intermediate formed in solution, isomerisation and cleavage at aspartate 3 depend on the ionisation state of a dissolved side chain (Bongers, International Journal of Peptide and Protein Research, 1992), and oxidation of methionine 27 is a solution-phase process (Campbell, Peptides, 1994). In a dry, sealed cake, molecular mobility is too low for these to proceed at any meaningful rate over days.
The approved medicine shows this clearly: its lyophilised vials are labelled for storage at 20 to 25 °C, with excursions to 15 to 30 °C permitted (US prescribing information, 2025). That rating belongs to that formulation and its excipients, but it illustrates how robust the dry peptide is. A few days in the post at ordinary temperatures is well within what lyophilised tesamorelin tolerates. An ice pack could add a risk instead, because condensation on a cold vial can work its way under a cap.
More on shipping within Canada is in ordering peptides in Canada.
What to do first
- Leave the vials sealed. Do not open a vial to inspect the cake; the glass shows everything you need.
- Store them cold and dark. In the fridge at 2 to 8 °C for near-term use, or the freezer at -20 °C for longer storage, in the original box. One supplier rates the solid at least 4 years at -20 °C (Cayman Chemical, product information). The full windows are on how long does tesamorelin last.
- Do not mix on arrival unless the vial is needed now. A mixed vial has about a week, while a sealed vial keeps far longer.
- When you are ready to mix, warm the sealed vial to room temperature before opening, then follow the tesamorelin reconstitution page for water volumes and concentrations.
If your order included bacteriostatic water
Check the bacteriostatic water multi-dose vials in the same way as the peptide vials: glass intact, cap seated, crimp tight and the liquid clear. Keep them unopened, away from heat and light, until the day you mix, and swab the stopper before the first access. Background on the diluent is in bacteriostatic water explained.
Bench practice for the mixing day is on the handling page. Certificates for our compounds are published on the lab reports page.
Sources: Bongers J et al., Int J Pept Protein Res 1992 (PMID 1428526); Campbell RM et al., Peptides 1994 (PMID 7937325); Cayman Chemical, tesamorelin (acetate) item 42498 product information; US prescribing information for tesamorelin, revised 2025.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
