This means they could affect the absorption of vitamin B12, which can potentially lead to vitamin B12 deficiency or worsen it in someone who already has it
Our results indicated that neither GHK nor GHK-Cu showed cytotoxic activity at the range of concentrations tested while CuCl 2 and Cu(OAc) 2 showed substantial cytotoxicity to the HaCaT cells at the highest concentration assayed, i.e., at 5800 M, after 30 mins treatment
For the chronic dosing studies, most studies are looking at doses of 4 g/day.[ref] (This used to be the maximum recommended acetaminophen dose per day, but that has now changed to 3g/day.) For reference, a single over-the-counter Extra Strength Tylenol is 500 mg, with the directions saying not to exceed 6 tablets in 24 hours (so 3g/day)
Safety Assessment of Tripeptide-1, Hexapeptide-12, Their Metal Salts and Fatty Acyl Derivatives, and Palmitoyl Tetrapeptide-7 as Used in Cosmetics
It often feels like nothing for the first 1-2 weeks
