GHK-Cu

The GHK-Cu evidence base cited here is 3 sources — 2 review. Regulatory status: Not FDA-approved (cosmetic).

• GHK-Cu is a naturally occurring copper tripeptide (glycine-histidine-lysine bound to a copper ion) found in human plasma, saliva, and urine — first identified by Loren Pickart in 1973. Plasma levels fall with age.
• It's unusual because the copper isn't just structural: it acts as an enzyme cofactor (superoxide dismutase for antioxidant defense, lysyl oxidase for collagen/elastin cross-linking), so the peptide is both a signaling molecule and a copper-delivery system.
• Every published human clinical result is from TOPICAL use. There are zero human trials of injectable (subcutaneous) GHK-Cu — injectable dosing and timelines are extrapolated from animal data and community reports.

GHK-Cu (copper peptide) is a small tripeptide — glycine, histidine, and lysine — complexed with a copper ion. It's one of the best-known regenerative/aesthetic peptides, studied for wound healing, skin rejuvenation, collagen synthesis, hair-follicle support, and anti-inflammatory effects, and is popular with anti-aging and biohacking crowds.

Two honest caveats up front. First, the human evidence is essentially all topical — injectable GHK-Cu has no published human trials, so any subcutaneous protocol is extrapolation. Second, the famous claim that it 'modulates 4,000+ genes' comes from a computational database prediction, not lab measurement in people. The wound-healing and collagen biology is genuinely well-characterized; the sweeping longevity claims are not. Everything below is research context, not medical advice.

Formally glycyl-L-histidyl-L-lysine copper complex, GHK-Cu is an endogenous peptide — your body already makes, uses, and metabolizes it. It was first isolated from human plasma in 1973, and its circulating concentration drops substantially with age (reported at roughly 200 ng/mL around age 20, falling to ~80 ng/mL by age 60), which is part of why it's framed as a 'youth' signal that supplementation might restore.

By the numbers it is tiny: a ~405 Da tripeptide (Gly-His-Lys + Cu²⁺). Systemic pharmacokinetics are very fast — reported peak within minutes, a half-life on the order of ~4 minutes, and near-complete clearance inside ~20 minutes. That extremely short systemic half-life is one practical reason the human evidence centers on topical/local delivery, where the peptide acts at the application site rather than relying on sustained circulation.

Its defining feature is the copper ion. In many peptides a metal is incidental; here the copper is functional, serving as a cofactor that drives enzymatic processes (antioxidant SOD activity, collagen/elastin cross-linking via lysyl oxidase) and gets delivered to tissue where copper is needed for repair and new blood-vessel formation.

No FDA-approved dosing exists. The figures below come from preclinical research and community use, included for research context only. Critical caveat: published human studies use topical application — all injectable dosing is extrapolated.

• Starting (subcutaneous): ~0.5 mg once daily
• Standard: ~0.5–1 mg once daily
• Anti-aging skin protocols: some use 2–3× weekly rather than daily
• Topical: 0.1%–1% concentration creams/serums, once or twice daily
• Cycling: commonly 4–8 weeks on, 2–4 weeks off; some extend to 12 weeks for wound healing or hair goals

Cycling is suggested to limit receptor desensitization. Start at the minimum effective dose and titrate to response.

These timelines reflect topical use and anecdotal reports — there are no controlled human trials of injectable GHK-Cu, so injectable timelines are extrapolated from animal data.

• Weeks 1–2: reported improvements in skin hydration/texture and a subtle 'glow'; in animal wound models some wounds closed within ~14 days.
• Weeks 3–4: reported gains in firmness/elasticity and softening of fine lines; measurable collagen/ECM changes in animal models.
• Weeks 6–8: more visible skin-quality improvement, including wrinkle-depth reduction in reports.
• Weeks 8–12: where extended-cycle users report peak benefits — collagen remodeling, scar improvement, hair-density gains.

Response varies with age, baseline skin condition, dose, and consistency. Photo documentation helps track changes objectively.

The literature spans decades of in-vitro and animal work, plus topical human use. The recurring limitation: large-scale human clinical trials — especially for injectable use — are absent.

• Stimulates collagen I/III, elastin, and glycosaminoglycan synthesis in fibroblasts and skin models.
• Shifts pro-inflammatory cytokines (TNF-α, IL-6, TGF-β) toward anti-inflammatory outcomes.
• Upregulates antioxidant defense via copper-dependent SOD activity.
• Accelerates wound re-epithelialization and granulation-tissue formation in animal wound models.
• Enlarges hair follicles and stimulates follicle growth in rodent models.

The wound-healing and collagen-synthesis data is robust and mechanistically well-understood. The Connectivity Map gene-modulation data is compelling but computational — hypothesis-generating, not confirmatory.

As of 2026 there's no research validating these combinations, but GHK-Cu is commonly stacked for recovery and aesthetics. Research context, not protocol advice. Introduce one compound at a time to gauge individual response.

• GHK-Cu + BPC-157 — complementary repair: BPC-157 for gut/tendon, GHK-Cu for systemic collagen/skin support.
• GHK-Cu + TB-500 — healing stack pairing TB-500's cell migration/angiogenesis with GHK-Cu's collagen stimulation.
• GHK-Cu + Epithalon — for anti-aging/longevity-oriented protocols.
• GHK-Cu + GH secretagogues (Ipamorelin, CJC-1295) — for recovery synergy.

• Reconstitute lyophilized powder with bacteriostatic water added slowly down the vial wall; let it dissolve, don't shake vigorously.
• Unreconstituted: store cool, dry, away from light; refrigeration extends shelf life but isn't strictly required short-term.
• Reconstituted: refrigerate at 2–8°C and use within ~4–6 weeks. Bring to room temperature and alcohol-clean the stopper before drawing a dose.

GHK-Cu has a favorable safety profile, consistent with it being an endogenous peptide the body already produces and clears. Human safety data for injectable use specifically is limited; reports are mostly from topical use.

The main, well-defined safety concern is copper homeostasis (Wilson's disease). Serious adverse effects are otherwise rare in reports.

• Not FDA-approved as a drug for any medical indication.
• Topical GHK-Cu is widely and legally sold as a cosmetic ingredient — cosmetic products are regulated differently from injectables.
• Injectable/research-grade GHK-Cu sits in the research-chemical gray area; sold 'for research purposes,' not for human consumption.
• Not a DEA-controlled substance; legal to possess in most jurisdictions.

Purity and potency vary widely between suppliers — source verification matters, especially for any injectable use.

GHK-Cu is not currently on the WADA Prohibited List (as of 2026), unlike BPC-157 and TB-500. That said, peptides face growing anti-doping scrutiny and the list changes yearly — tested athletes should verify the current list with their governing body before use rather than assume permanent permitted status.

On the Huberman Lab podcast, Dr. Abud Bakri sorted GHK-Cu's evidence into tiers. Topical GHK-Cu has the best human data (photo-aged skin; its discoverer Loren Pickart compared it favorably to retinol and vitamin C) and shows interesting synergy with red/near-infrared light. A practical authenticity check he offered: a genuine copper-peptide product should be visibly blue — many 'research-chem' topicals are not.

He was less impressed by the hair evidence (not superior to minoxidil despite marketing), noted that injectable GHK-Cu lacks good human data and is not FDA-approved, and strongly cautioned against facial self-injection by non-experts. He also observed that GHK-Cu drives a large and growing share of the women's peptide market.

Expert commentary from a podcast — the topical-versus-injectable evidence gap is the key takeaway.

All citations link to the original source (PubMed, journal site, or regulatory filing). Independent research database — no vendor influence on what's cited.