Two different shelf-life clocks
An unopened, lyophilised retatrutide vial has a longer shelf life than most people expect when kept refrigerated and away from light, often measured in months. Reconstituting it starts a second, much shorter clock.
Before reconstitution
Manufacturer data for similar peptides commonly points to refrigerated lyophilised powder remaining stable for an extended period, frequently cited in the range of many months to roughly two years depending on the specific formulation and storage conditions. This isn’t a guarantee for every product, and a batch’s own documentation should take priority over a general figure.
After reconstitution
Once bacteriostatic water is added, most guidance for similar peptides suggests using the vial within about 2-4 weeks when kept refrigerated at 2-8°C. This shorter window is why many people reconstitute only what they expect to use within that stretch, rather than mixing an entire supply at once.
Signs a reconstituted vial may no longer be good
Visible cloudiness, discoloration, or particles in a solution that was previously clear are commonly cited signs a reconstituted peptide shouldn’t be used, though the absence of visible changes doesn’t guarantee potency hasn’t declined.
Tracking it properly
Writing the reconstitution date directly on the vial with a permanent marker is a simple habit that removes any guesswork later about how long a given vial has actually been in use.