Glycyl-L-Histidyl-L-Lysine Copper
(aka GHK-Cu)
A copper tripeptide your body already makes — and quietly stops making with age.
It activates fibroblasts. It signals collagen, elastin, and glycosaminoglycan production. It modulates over 1,500 human genes tied to repair, inflammation, and regeneration. And it's been studied for fifty years.
Most skincare sits on top. GHK-Cu signals.
50+
Years of peer-reviewed research
2%
Pure GHK-Cu in every Loop product
1,500+
Human genes GHK-Cu modulates
55.8%
Wrinkle volume reduction in 8 weeks
Four things to know before you scroll any further.
01 — What it is
3 amino acids. 1 copper ion.
Glycine, histidine, and lysine, bound to copper. Your skin produces this peptide naturally — abundant in your twenties, dropping by more than half by your sixties.
Replacing what your skin no longer makes is the entire premise.
02 — How it works
1,500+ genes activated.
GHK-Cu binds to receptors on fibroblasts — the cells responsible for collagen, elastin, and glycosaminoglycans — and tells them to get back to work.
It's not a building block. It's the instruction.
03 — What it supports
Firmness. Density. Resilience.
Increased collagen and elastin. Improved antioxidant activity. Reinforced barrier. Better micro-circulation.
The visible result is what you'd expect — skin that looks firmer, denser, and more bouncy over time.
04 — Why 2%
The dose the research actually uses.
Most peptide products use trace amounts — 0.05% to 0.5% — that wouldn't show meaningful results in the studies the molecule is famous for.
Our serum and cream are formulated at 2% pure GHK-Cu. The clinical-strength dose, undiluted.
The science is in. The skin is yours.
Two products, one molecule, eight weeks. We built the Glow Set so fifty years of research could finally do what it's been proving — at home.
Shop the Glow Set
50+ years of peer-reviewed research back GHK-Cu.
Here's the work we lean on. All links go to the full published research — read, challenge, decide for yourself. That's the Loop way.
Collagen & skin regeneration
The foundational modern review.
Covers GHK-Cu's role in collagen synthesis, glycosaminoglycan production, wound healing, and fibroblast activation. Referenced across the industry as the definitive primer.
Read paper →GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration.
BioMed Research International, 2015.
1,500+ genes modulated by GHK-Cu.
Gene-level review documenting GHK-Cu's ability to modulate over 1,500 human genes connected to repair, inflammation, and regeneration — based on independent Broad Institute data. The paper behind the "resets DNA back to a healthier expression pattern" claim.
Read paper →Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data.
International Journal of Molecular Sciences, 2018.
An independent third-party review.
University of Washington researchers — not Pickart-authored. A third-party look at the same body of evidence, reaching the same conclusions on collagen, wound healing, and anti-inflammatory activity.
Read paper →The Potential of GHK as an Anti-Aging Peptide.
Aging Pathobiology and Therapeutics, 2020.
Anti-aging & photoaging
55.8% wrinkle reduction in 8 weeks.
Forty women aged 40–65, twice-daily topical GHK-Cu, randomized double-blind placebo-controlled. Results: 55.8% reduction in wrinkle volume vs. vehicle (p<0.001), 31.6% reduction vs. Matrixyl 3000 (p=0.004), and 32.8% reduction in wrinkle depth (p=0.012). Increased collagen and elastin production confirmed in parallel cell-culture work.
Read paper →Randomized, Double-Blind Clinical Trial on Facial Wrinkle Reduction.
Journal of Aging Science, 2016.
Density, clarity, and softer fine lines.
Twelve weeks of GHK-Cu facial cream produced increased skin density and thickness, reduced laxity, improved clarity, softer fine lines, and reduced wrinkle depth in women with mild to advanced photoaging.
Read paper →GHK-Cu Facial Cream Trial. Presented at the American Academy of Dermatology, 2002.
Referenced in Pickart & Margolina, 2018.
Beat both placebo and vitamin K cream.
A GHK-Cu eye cream outperformed both placebo and a competing vitamin K eye cream on lines, wrinkles, skin density, and thickness over twelve weeks in women with mild to advanced photodamage.
Read paper →GHK-Cu Eye Cream Trial. Presented at the American Academy of Dermatology, 2002.
Referenced in Pickart & Margolina, 2018.
Wound healing & tissue repair
Stanford research on damaged fibroblasts.
GHK-Cu restored irradiated fibroblasts' growth rate to that of healthy controls and increased early production of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) — both critical for wound repair. Explains why GHK-Cu pairs well with post-procedure skin (microneedling, resurfacing).
Read paper →Effects of Copper Tripeptide on the Growth and Expression of Growth Factors by Normal and Irradiated Fibroblasts.
Archives of Facial Plastic Surgery, 2005.
Antioxidant & protective actions
The antioxidant mechanism explained.
Reviews GHK-Cu's antioxidant and anti-inflammatory mechanisms, including how it modulates iron to block lipid peroxidation and how it regulates genes tied to oxidative stress response.
Read paper →The Human Tripeptide GHK-Cu in Prevention of Oxidative Stress and Degenerative Conditions of Aging.
Oxidative Medicine and Cellular Longevity, 2012.
We read everything. If you find a study you think we should see — contact us.
The history of GHK-Cu.
