Amazon.com: Neurogan GHK Cu Copper Peptide Hair & Scalp Serum 2400mg, 4% Copper Peptides Fast Absorbing, Water Based Formula for Hair Softness & Shine Cosmetic Dry Scalp Moisturizer Spray, Made in USA : Essential GHK Cu Serum: What It Is, How It Works, and Why It Matters f Bacteriostaticwater.com GHK Cu Copper Peptide: The Ultimate Peptide For Longevity A lot of people asked how I use GHK Cu (copper peptide) with a pen device, so here's a quick tutorial showing exactly how I do it. In this video I show how The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds,