TB-500 On Arrival: What to Check and Do First

When a TB-500 order arrives, check that each vial’s seal and cap are intact and that the contents look like a dry white cake or powder, then put the sealed vials in the fridge for near-term use or the freezer for longer holding. Lyophilised TB-500 is a dry, chemically robust material, so it does not need an ice pack in transit.

Why TB-500 travels without ice

A lyophilised vial contains the peptide as a freeze-dried cake with almost no water. Every degradation route that matters for TB-500, from slow hydrolysis to the enzymatic cutting at its lysines that has been mapped in serum and enzyme systems (Rahaman et al., Journal of Chromatography B, 2024), needs water to proceed. In the dry, sealed state those routes have very little to work with.

The sequence adds a second layer of protection. TB-500, Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln, has no methionine, cysteine, tryptophan, histidine or tyrosine, so the oxidation that makes some peptides sensitive to air and warmth is not a concern. The methionine that oxidises in full-length thymosin beta-4 sits at position 6 (Huff et al., European Journal of Biochemistry, 1995), outside the 17 to 23 fragment. It also has no asparagine and no aspartic acid, so deamidation and isomerisation have almost nothing to act on.

Every Vistara Labs order ships from within Canada by Canada Post Xpresspost, so the vials stay in the domestic network without a customs hold. A few days at room temperature in transit does not harm sealed TB-500 powder. An ice pack would add condensation risk inside the parcel without protecting anything.

What to check, vial by vial

The seal and cap

Each vial should have its crimped aluminium seal intact and the plastic flip-off cap in place over the rubber stopper. The cap protects the stopper surface from dust and handling. A cap that has popped off in transit does not by itself mean the vial is open; the crimp and stopper are the actual closure. If the crimp is loose or the stopper is visibly pushed in or pierced, contact us before using the vial. A sealed closure matters for TB-500 in particular, because contamination is its main route of breakdown once mixed.

The glass

Look for cracks or chips, especially around the neck. Intact glass and an intact crimp mean the vial is sealed.

The cake or powder

Lyophilised TB-500 is white to off-white. A 10 mg fill is a small amount of material, so expect a compact cake or pellet at the bottom of the vial, not a full plug. It is normal for:

• the cake to have shrunk away from the glass or cracked into pieces;
• the cake to have broken up into loose powder that moves when the vial is tilted;
• powder to be scattered up the walls or on the underside of the stopper after travel.

None of these affect the peptide. Freeze-dried cakes are fragile and shift with handling. Tap the vial gently on the bench to settle the powder before reconstituting.

What would warrant a question is a cake that looks wet, syrupy or collapsed into a glassy film, or that has a yellow or brown tint. Those suggest moisture got in. Because TB-500 itself is colourless and has no aromatic residues to discolour, any tint is worth asking about.

The nasal spray

The TB-500 Nasal Spray is different: it arrives ready-mixed in sterile saline in a sealed metered pump. Because it is already a solution, it goes into the fridge upright as soon as it arrives. See how to store a peptide nasal spray.

What to do first

1. Leave the vials sealed. Do not open or reconstitute a vial until it is needed. The dry cake is the most stable form TB-500 will ever be in.
2. Decide fridge or freezer. Vials for use in the coming weeks go in the fridge at 2 to 8 °C. Vials to be held for months go in the freezer at minus 20 °C. The full windows are on how long TB-500 lasts.
3. Keep them boxed and dark. Store vials in their box in the main body of the fridge or freezer, not in the door.
4. Store the bacteriostatic water separately. Unopened bacteriostatic water keeps at room temperature; once its stopper has been pierced it is kept cool and used within its own window.
5. When you are ready to mix, let the vial warm to room temperature before piercing it so condensation does not form on the powder. The method is on the TB-500 handling page and the volumes on the TB-500 reconstitution page.

If the parcel sat somewhere warm

A parcel left in a mailbox or a warm vehicle for an afternoon is not a problem for sealed lyophilised TB-500, for the reasons above. Move the vials to cold storage when you get them and proceed as normal. A mixed vial or the ready-mixed spray is different, because it is already in solution; those should be refrigerated promptly.

More on TB-500

How the peptide holds up over time is on the TB-500 stability page. Our certificates are on the lab reports page.