GHK-Cu
Also known as: Copper Peptide · Glycyl-L-Histidyl-L-Lysine Copper
The copper-binding tripeptide your skin loses with age. Strongest evidence is topical for skin and wound healing; injectable use is mostly anecdotal.
Overview
GHK is a short, naturally occurring tripeptide (glycyl-L-histidyl-L-lysine) that the human body produces in plasma and that binds copper(II) with high affinity. Tissue levels drop with age, which is part of what put it on the anti-aging map in the first place. The topical evidence is the cleanest part of the file — randomised trials of GHK-Cu creams show measurable improvements in skin density, fine lines, and wound healing at clinically meaningful effect sizes. The injectable case is where the literature gets thinner and the marketing gets louder. Most claimed systemic benefits — hair regrowth, joint repair, gut healing — rest on cell-culture data and user reports rather than human trials.
Evidence quality
Topical cosmetic and wound-healing data is the strongest part of the literature — small but real RCTs from the 1990s and 2000s for skin firmness, wrinkle depth, and diabetic ulcer healing. Loren Pickart's group has been the principal driver of this research for decades. Injectable systemic use has minimal human trial data and the gene-modulation claims that circulate online come from in vitro work, not clinical trials.
Benefits & timeline
Benefits
- Topical: measurable improvement in skin firmness, fine lines, and barrier function over 8–12 weeks of consistent use
- Wound healing — older but solid clinical literature, including studies in diabetic foot ulcers
- Some users report hair regrowth at the temples and crown with topical or scalp-injected protocols
- Anti-inflammatory and mild antioxidant activity, plus a copper-delivery effect that supports collagen and elastin synthesis
Timeline
Week 2
Skin starts to feel slightly softer; barrier improvements show up before visible changes.
Week 4
Visible reduction in fine lines and improvement in tone for topical users; injectable users sometimes notice the same plus a subtle skin colour shift.
Week 8–12
Plateau of the cosmetic effect. This is the window where you assess whether it's working.
Off-cycle
4 weeks off lets you see whether the gains hold without continuous dosing.
Dosage protocols
Advanced
3 mg
three times weekly
Beginner
1 mg
twice weekly
Standard
2 mg
three times weekly
Titration & adjustment
Start at 1 mg subcutaneously twice weekly. After 2 weeks escalate to 2 mg three times weekly. Maximum 3 mg three times weekly. Topical forms (creams at 1–2% GHK-Cu) can be used daily without titration.
Injection timing
Subcutaneous 2–3× weekly. Time of day does not matter. Topical creams: apply morning and evening on clean skin, ideally before sunscreen in the AM.
Side effects & contraindications
- mildInjection-site soreness or a small bluish bump that resolves in 24–48 hours — the copper colour is normal.
- mildTopical irritation in sensitive skin, usually from the carrier rather than the peptide.
- mildTransient drop in blood pressure with high subcutaneous doses in some users — minor, but worth noting if you're already on antihypertensives.
- moderateNo long-term human safety data for injectable use at the doses people are running.
Contraindications
- Wilson disease — copper handling is exactly what you don't want to challenge in someone whose body cannot clear it
- Active cancer — the peptide promotes angiogenesis and tissue regeneration, both of which are double-edged in this context
- Pregnancy and breastfeeding — no safety data
- Caution if you're already supplementing copper at high doses; the peptide brings its own
Reconstitution & injection
A 50 mg vial reconstituted with 2 ml bacteriostatic water gives 25 mg/ml. A 2 mg dose is 0.08 ml, which is 8 units on a U-100 insulin syringe. The reconstituted liquid takes on a distinct blue colour — that's the copper, and it's correct. Subcutaneous injection rotates around the abdomen or thigh. For topical use, dissolved GHK-Cu at 1–2% in a clean carrier (a hyaluronic acid serum works) is the standard formulation; apply morning and evening on cleansed skin.
Open calculator pre-filledStorage after reconstitution
Refrigerate at 2–8 °C after reconstitution. Do not freeze. Light-protected (less critical than for NAD+ but still good practice). 28–30 days of stability at fridge temperature in BAC water. The characteristic blue/teal colour will deepen over the dosing window — this is the copper-peptide complex behaving normally and is NOT a degradation signal. Cloudiness or precipitate is a degradation signal; deepening colour is not. Topical GHK-Cu serums: follow the product label; most are stable at room temperature for the printed shelf life.
Common mistakes
Injecting systemically and expecting topical-grade skin results.
Better approach: The strongest skin evidence is for topical formulations applied directly to the area you want to improve. Subcutaneous injection in the abdomen is unlikely to outperform a well-formulated cream applied to your face.
Stacking it with high-dose vitamin C topical.
Better approach: Ascorbic acid reduces the copper in GHK-Cu and breaks the complex. Layer them on opposite ends of the day — vitamin C in the morning, GHK-Cu in the evening — or in alternating routines. Same skincare benefit, no cancellation.
Running it indefinitely without an off-cycle.
Better approach: The skin remodelling effect plateaus around week 12. Continued daily exposure beyond that doesn't add visible improvement and slowly accumulates copper. Cycle 8–12 weeks on, 4 weeks off.
Buying it as a generic 'copper peptide' powder.
Better approach: Quality varies wildly. The peptide is hygroscopic, copper content matters, and the difference between a working product and a useless one is real. Buy from a source that publishes a certificate of analysis, or formulate from a known-quality raw.
Real-world tips
- The blue colour is the copper. If your reconstituted vial isn't faintly blue, you may have purity issues with the raw.
- Store reconstituted vials in the fridge; copper-binding peptides degrade faster than naked peptides at room temperature.
- Layer topical GHK-Cu underneath moisturiser, not on top. The barrier-occlusive layer goes last.
- Photo-track. The visible improvements happen slowly enough that day-to-day memory can't see them; weekly photos in consistent lighting can.
- For hair claims, scalp microneedling combined with topical GHK-Cu is the protocol with the most anecdotal traction. Solo topical without microneedling is much weaker.
When something else is the better tool
Topical retinoids
Use instead when: The primary goal is anti-aging and the budget only stretches to one active. Tretinoin has decades of evidence and is cheaper. Add GHK-Cu as a layered companion if you tolerate retinoids well.
BPC-157
Use instead when: The need is acute tissue injury (tendon, ligament) rather than slow cosmetic remodelling. BPC-157 is faster and more localised; GHK-Cu is slower and more cosmetic.
Microneedling with PRP
Use instead when: Skin density and texture is the target and you have access to a clinic. Mechanical and growth-factor mechanisms are complementary; many users do GHK-Cu plus periodic microneedling sessions.
- Topical or injectable?
- For skin, the topical case is stronger and the side-effect ceiling is lower. Injectable becomes more interesting if your goal is systemic — joints, hair, general anti-aging — but the evidence there is anecdotal.
- Do I need a separate copper supplement?
- No. The peptide is named GHK-Cu because the copper is already bound. Additional supplementation can disrupt the binding and isn't needed for the peptide to work.
- Why is my injection bluish?
- Copper ion absorbs in the red end of the spectrum, so the solution looks blue. The colour is normal and the local discolouration at the injection site fades in a day or two.
- Can I dose more often?
- Past three injections weekly the dose-response goes flat. More frequent injections give you more soreness without more benefit.
- Does it work for hair?
- The hair claim is the weakest part of the file. Scalp-applied topical with microneedling has the most anecdotal traction; oral and systemic use for hair is essentially unsupported.