The most chemically varied group in the catalogue, and the one containing our favourite certificate quirk: GHK-Cu arrives as a blue powder, and that is exactly right.
GHK-Cu
Three amino acids wrapped around a copper ion. Found in human plasma, where the amount present falls markedly with age, which is the observation that launched decades of work on what it is doing there.
Glutathione
The cell’s principal antioxidant, present at unusually high concentrations, with the whole story hanging off a single sulphur atom.
Combination preparations
Glow and Klow are prepared blends. Their component compounds and quantities are listed on their product pages, and each component appears on the certificate rather than being described only as a proprietary total.
What ties them together
Less mechanism than setting. These are compounds studied at the level of the cell and its immediate environment: redox state, copper handling, the extracellular matrix. It is the broadest grouping here and the one where the compounds have least in common chemically.
Handling
Varies more than elsewhere in the catalogue, so the specification table on each product page is worth reading rather than assuming the group behaves alike. Glutathione in particular oxidises readily and is prepared fresh.