GHK
What do these badges mean?
Evidence tier
- AHuman-validated — Human trials showing positive results and good safety.
- BAnimal-grade — No human trials yet, but solid animal/preclinical evidence of effect and safety.
- CAnecdotal — No human or animal trials — only anecdotal/observational reports.
- DInsufficient evidence — No or insufficient evidence (encyclopedia only — never recommended by the builder).
Safety light
- 🟢 Green — Only mild, manageable side effects; reasonable safety data.
- 🟡 Yellow — Needs active management, has a meaningful contraindication/interaction, or has thin long-term data.
- 🔴 Red — Risk of a hospital-level event — treat with serious caution.
Browse-only — not on the protocol builder's curated shortlist, so the builder won't recommend it.
What is it?
GHK is the non-copper-coordinated form of the GHK tripeptide (Gly-His-Lys) — the base molecule behind GHK-Cu, the copper-bound compound that anchors the whole copper-peptide family in this cluster (alongside Pal-GHK, AHK-Cu, and Pal-AHK).
What does it do in my body?
GHK modulates gene expression related to tissue remodeling, collagen synthesis, and wound healing.
How can it help me?
- Where the science stands: Moderate — 30 studies including human and animal (the strongest evidence base in the cosmetic-topical cluster); OHM grades it Tier B by extrapolation from the GHK-Cu literature
The full evidence — every human, animal, and lab study, graded — is one tap away: use the See the deeper science → toggle at the top.
Is it dangerous? What are the side effects?
No adverse-effect data specific to the free-base (non-copper) form was captured in the source profile beyond what’s documented for the copper-bound compound. See GHK-Cu for the detailed safety and side-effect picture, which largely applies to this parent molecule.
Regulatory status: The source material does not distinguish a separate regulatory status for free-base GHK from the copper-bound form. See GHK-Cu for the full regulatory picture (topical = legal OTC cosmetic; injectable = research-use-only, with an evolving FDA compounding-list status).
Typical dosing
Educational context only — talk to a licensed medical provider before any protocol. What follows describes the doses and schedules most commonly reported in the research and by practitioners, shared so you can have an informed conversation. These compounds are sold for research use only, are not FDA-approved drugs, and this is not medical advice.
The source material for free-base GHK does not carry its own distinct dosing protocol separate from the copper-bound compound; OHM’s copper-family framing treats GHK-Cu as the practical, commercially relevant form (topical or injectable). No standalone free-base GHK protocol was captured in the source.
What should I avoid combining — and what's synergistic?
GHK doesn't have a dedicated stacking protocol in our notes — the interactions that matter most are in the safety section above. For how people combine it with other peptides, the deeper-science view has the full detail.
Where do people source this?
OHM does not sell or handle any compound. Research-use-only material is sold by third-party vendors; our vetting notes and disclosures are on the Where to buy page. If you'd rather have a physician in the loop, see the telehealth option. Whatever the route, the supply chain is the real risk: only consider vendors that publish batch-level third-party Certificates of Analysis.
The un-coordinated form of the tripeptide behind GHK-Cu — the anchor of the whole cosmetic-peptide copper family, even though most of the real evidence belongs to the copper-bound version. If you’re looking for the deep evidence dive, GHK-Cu is where it lives; this article covers the free-base form specifically.
| Class | Copper peptide family (non-copper-coordinated form) — topical/systemic |
| Mechanism (one line) | Modulates gene expression related to tissue remodeling, collagen synthesis, and wound healing |
| Evidence base | Moderate — 30 studies including human and animal (the strongest evidence base in the cosmetic-topical cluster); OHM grades it Tier B by extrapolation from the GHK-Cu literature |
| Safety record | Safety: green |
What it is
GHK is the non-copper-coordinated form of the GHK tripeptide (Gly-His-Lys) — the base molecule behind GHK-Cu, the copper-bound compound that anchors the whole copper-peptide family in this cluster (alongside Pal-GHK, AHK-Cu, and Pal-AHK).
How it works
GHK modulates gene expression related to tissue remodeling, collagen synthesis, and wound healing.
What the research shows
This is the strongest evidence base in the entire cosmetic-topical cluster: the public profile grades free-base GHK Moderate, with 30 studies including human and animal. Genuine on-target findings include:
- A crow’s-feet case report with increased collagen and elastic-fiber production (Byun et al., 2016, PMID 27064823).
- Multiple GHK-Cu studies in wound healing, lung fibrosis, and smoking-induced muscle dysfunction (e.g. PMID 36905132, PMID 28370978, both).
Honesty note: the profile’s #1-cited “RCT, n=1600” is a children’s-bodyweight intervention trial that’s an off-target database match, not a GHK study.
OHM’s internal 0035 categorization pass grades free-base GHK Tier B / green / recommend-eligible ( + SECONDARY heal-recover) — “Tier B by extrapolation from the GHK-Cu literature” — noting that the copper-coordinated form drives most of the documented benefit.
Status: the anchor of the cosmetic-peptide world by reputation, but most of the real evidence belongs to the copper form.
Real-world protocol
The source material for free-base GHK does not carry its own distinct dosing protocol separate from the copper-bound compound; OHM’s copper-family framing treats GHK-Cu as the practical, commercially relevant form (topical or injectable). No standalone free-base GHK protocol was captured in the source.
Side effects & management
No adverse-effect data specific to the free-base (non-copper) form was captured in the source profile beyond what’s documented for the copper-bound compound. See GHK-Cu for the detailed safety and side-effect picture, which largely applies to this parent molecule.
Regulatory status
The source material does not distinguish a separate regulatory status for free-base GHK from the copper-bound form. See GHK-Cu for the full regulatory picture (topical = legal OTC cosmetic; injectable = research-use-only, with an evolving FDA compounding-list status).
Sources
- (thepeptidelist.com directory, captured 2026-06-07) — profile grade: Moderate, 30 studies, human + animal. Studies cited: Byun et al., 2016, PMID 27064823; PMID 36905132; PMID 28370978.
- OHM tier/safety grading: Tier B / green / recommend-eligible ( + SECONDARY heal-recover), by extrapolation from the GHK-Cu literature.
- Migrated from
cosmetic-topical-peptides-cluster.md(2026-06-10 cluster build) as part of the cluster-to-standalone-article migration.
Sources & references
- (thepeptidelist.com directory, captured 2026-06-07) — profile grade: Moderate, 30 studies, human + animal. Studies cited: Byun et al., 2016, PMID 27064823; PMID 36905132; PMID 28370978.
- OHM tier/safety grading: Tier B / green / recommend-eligible ( + SECONDARY heal-recover), by extrapolation from the GHK-Cu literature.
- Migrated from
cosmetic-topical-peptides-cluster.md(2026-06-10 cluster build) as part of the cluster-to-standalone-article migration.