GLOW vs KLOW Peptide Stacks: What's the Difference? Let's cut through the marketing noise and look at the actual science of fat loss. A lot of supplements make big claims, but L Carnitine is heavily backed by research for its Cla+Carnitine Bpi Sport Gold Nutrition 12 weeks in, and my skin has NEVER looked better! GHK peptides are doing their thing. Alright, I need to give you an updateit's been 12 weeks since I started using GHK