Cosmetic-grade vs research-grade GHK-Cu — does it matter for topical use?

I do. Caveats: buy from a supplier that publishes a CoA with HPLC purity, reconstitute in a clean environment (isopropyl wipe everything, gloves, use preserved base), make small batches. The molecule is the molecule — purity is the only variable.

Cosmetic-grade premixed also has the advantage of validated preservatives and stability testing. For face use specifically, 'research-grade in your kitchen' is fine for 2 weeks refrigerated, not fine for 6 months on a bathroom shelf.

Makes sense. Small batches it is.

The cost differential is real — you can make a year of 0.1% serum from a single 100mg research vial for under $30. Just treat it like a compounding exercise and don't be gross.

Been doing this for like 4 months now. Got a vial from a research supplier with a legit CoA, mixed it in some hyaluronic acid base with a few drops of preservative. Honestly the hardest part was not overthinking the sterility thing. Just wipe down your workspace, use clean containers, keep it in the fridge. Way cheaper and honestly works the same as the cosmetic stuff I tried before, just takes like 15 mins of work upfront.

Did the research powder route for a few months. Honestly the purity difference is negligible if you're buying from somewhere with a legit CoA, and yeah the cost savings are stupid good. My only real concern was contamination but that's more about being not lazy than anything actually risky. Use sterile containers, keep it in the fridge, dont let it sit around for months and you're fine. Works just as well as the cosmetic stuff imo.