There’s been some fear mongering circulating because a creator made a video saying you shouldn’t refrigerate Tesamorelin.
Here’s the thing—he was talking about Egrifta, the pharmaceutical version. That’s a completely different situation than what most of you are working with.
Huge shout out to Barry for digging deeper into this. Let me explain why RUO (research-use-only) Tesamorelin is fundamentally different, and why you should absolutely still refrigerate it like every other lyophilized peptide.
Yes, Egrifta and RUO Tesamorelin share the same active ingredient. But Egrifta is an FDA-approved product held to a much higher standard for purity, excipients, endotoxins, and stability.
This is exactly why context matters—”gray market” products, while chemically similar, a lot of the times don’t have the same stabilization ingredients.
RUO tesamorelin is not manufactured under drug GMP the way an FDA-approved product is. Even when a vendor provides a COA, it may not cover the same parameters, not to the same standard, and sometimes not even for the final vial you receive.
This is a common problem in the industry: a bulk batch gets tested, then aliquoted into individual vials later—meaning your specific vial may not have been directly tested.
EGRIFTA WR isn’t just peptide in bacteriostatic water. It’s a deliberately engineered formulation designed for room temperature stability:
Hydroxypropyl-β-cyclodextrin — stabilizes peptide conformation
Tightly buffered pH (≈4.5–7.4) — maintains optimal environment
This formulation was stress-tested during FDA stability studies at room temperature for 7 days. Refrigeration wasn’t required to preserve potency within that validated window.
In fact, the product was specifically engineered so that refrigeration adds no benefit—and may actually introduce instability through temperature cycling, condensation, or crystallization effects.
Your RUO Tesamorelin doesn’t have that sophisticated stabilization system. It’s a lyophilized peptide like any other, and it should be treated like one.
Refrigerate it.
Don’t let a video about a completely different product change how you handle your research materials. Context matters, and now you understand why.
Questions? Reply to this email or drop them in the community.
— Derek
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