TL;DR
A human plasma tripeptide from 1973. Strip the copper off, most of the published evidence goes with it.
What: The copper-free form of Gly-His-Lys. Same sequence as GHK-Cu, no chelated Cu²⁺. Endogenous to human plasma.
Does: Matrikine collagen signal, aldehyde scavenger, gene-expression modulator. In direct fibroblast assays, the apopeptide performs less strongly than GHK-Cu.
Evidence: Copper-independent evidence is thin: Choi 2012 on stem-cell preservation and Beretta 2007/2008 on aldehyde chemistry. No independent human RCT on the apopeptide.
Used by: Cosmetic formulators when copper conflicts with vitamin C or retinoids. Research-chemical channels sell the powder to the DIY community.
Bottom line: Endogenous to humans, weaker than GHK-Cu head-to-head. The copper is where the work gets done.
What It Is
GHK Basic is the copper-free form of the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys, or "GHK"). It has the same amino-acid sequence as GHK-Cu — the widely studied "copper peptide" used in cosmetic serums and research protocols since the 1980s — but is supplied without the coordinated Cu²⁺ ion that the parent peptide chelates with very high affinity (log cK7.4 ≈ 12.62 under physiological conditions). In chemistry terminology, GHK Basic is the apopeptide and GHK-Cu is the metallopeptide. Many vendors describe the product as "GHK," "GHK Basic," "copper-free GHK," "free GHK," or "GHK fragment."
The GHK sequence was first isolated from human plasma in 1973 by Loren Pickart, then at the University of California, San Francisco, who identified it as a small tripeptide that could promote the growth of cultured hepatoma cells and prolong the survival of normal hepatocytes (Pickart and Thaler, Nature New Biology 1973). Subsequent biochemical characterization — notably the Maquart et al. 1988 FEBS Letters paper demonstrating fibroblast collagen stimulation — was performed almost exclusively with the copper-bound form. That is why the literature, the cosmetic ingredient listings (INCI: "Copper tripeptide-1"), and the bulk of clinical interest all center on GHK-Cu rather than its copper-free counterpart.
GHK Basic became commercially interesting in the late 2000s when formulation chemists encountered practical problems combining GHK-Cu with high-concentration ascorbic acid (which reduces Cu²⁺ to Cu¹⁺ and destabilizes the complex) and with some peptide-compatible vehicles. A copper-free version solved those formulation conflicts and, in parallel, Choi et al.'s 2012 J Pept Sci paper reported that the apo-tripeptide retained meaningful biological activity in human skin-equivalent models — specifically, a stem-cell-preserving effect mediated through fibroblast-keratinocyte signaling that did not strictly require bound copper. Since then, a small body of literature has suggested that GHK and GHK-Cu share overlapping but non-identical biological profiles.
Practically, GHK Basic is used in two separate contexts: (1) as a cosmetic ingredient in topical serums and creams, where it acts as a gentle matrikine collagen signal without delivering exogenous copper; and (2) as a research peptide sold by research-chemical vendors as a less-studied sibling of GHK-Cu. Anyone choosing between the two should understand that the vast majority of published clinical and preclinical evidence uses the copper-bound form, and that under physiological conditions a copper-free GHK administered parenterally will rapidly encounter and bind endogenous copper — blurring the in-vivo distinction between "GHK" and "GHK-Cu" within minutes of administration.
Mechanism of Action
The scientifically interesting question is which GHK activities are copper-dependent and which are not. The literature supports three broad mechanistic categories for the copper-free tripeptide.
- Matrikine / fibroblast gene-expression signaling — GHK is a collagen-derived "matrikine" fragment. In cultured fibroblasts and human skin-equivalent models, the tripeptide modulates expression of large gene sets — Pickart and Margolina's Connectivity Map analyses report modulation of >4,000 human genes across samples of GHK-treated cells — with broad upregulation of DNA-repair, antioxidant, regeneration, and extracellular-matrix genes and downregulation of inflammatory and tumor-promoting pathways (Pickart, Vasquez-Soltero, Margolina 2014, 2015; Pickart and Margolina 2018, PMID 29986520). A fraction of these gene-expression changes are copper-dependent; others are not.
- Copper sequestration rather than copper delivery — Where GHK-Cu acts as a copper-delivery vehicle (chelating extracellular Cu²⁺ and trafficking it across membranes for downstream activation of lysyl oxidase, superoxide dismutase, and other copper-dependent enzymes), the copper-free tripeptide administered in vivo behaves like a copper sequestrant: it binds endogenous Cu²⁺ rather than delivering exogenous copper. The binding affinity is high enough (Trapaidze et al., 2012, J Biol Inorg Chem) that essentially any copper-free GHK injected parenterally will bind some Cu²⁺ from the recipient within minutes.
- Direct antioxidant activity (copper-independent) — Cebrián-Torrejón et al. (2018, PMC6055086) demonstrated that free GHK functions as a radical scavenger, quenching hydroxyl (·OH) and peroxyl (ROO·) radicals at low micromolar concentrations. This activity does not require bound copper and is sequence-specific to GHK rather than to the metal complex.
- Aldehyde / 4-HNE sequestration (copper-independent) — Beretta et al. (2007, Chem Res Toxicol; 2008, J Pharm Biomed Anal) showed that the histidine residue of GHK conjugates directly with 4-hydroxy-2-nonenal (4-HNE) and acrolein — toxic byproducts of lipid peroxidation. This reaction does not require copper and mirrors the aldehyde-scavenging activity of the dipeptide carnosine.
- Stem-cell preservation in human skin (Choi 2012) — In human skin-equivalent models, topical copper-free GHK preserved the p63-positive basal keratinocyte stem-cell population and reduced UV-induced damage. The proposed mechanism involves fibroblast-derived growth-factor signaling rather than direct copper-dependent collagen synthesis (Choi et al., J Pept Sci 2012;18:685-690).
- CNS / anxiolytic activity in rodents (Bobyntsev et al.) — A Russian literature from the Bobyntsev group (Russian Academy of Medical Sciences) has reported anxiolytic activity, neurotransmitter modulation, and cognitive effects in rodents after systemic GHK administration. The activity is attenuated by D-amino-acid replacement of the histidine or lysine, indicating sequence specificity. Mechanism unresolved; likely independent of the copper-binding axis.
- Direct fibroblast collagen stimulation is copper-dependent — In head-to-head fibroblast collagen-synthesis assays, GHK-Cu consistently outperforms the copper-free tripeptide. This is the cleanest case where the two forms diverge pharmacologically and argues against using GHK Basic alone for applications where fibroblast collagen stimulation is the primary goal.
- What is mechanistically certain — The copper-free distinction is most meaningful at the pre-administration product level. After parenteral dosing, in-vivo copper coordination is essentially inevitable given the binding affinity. Topical use on intact skin involves less endogenous copper contact, so the pre-bound vs unbound distinction matters more for topical formulations than for injected ones.
What the Research Shows
Research on the copper-free form specifically — as distinct from GHK-Cu — is thinner but not empty. The published findings that most cleanly address the copper-free case:
- Skin stem-cell preservation (Choi 2012) — In human skin-equivalent cultures of normal keratinocytes, copper-free GHK preserved p63-positive basal stem cells, reduced UV-induced damage, and restored fibroblast-keratinocyte interaction-dependent growth factors (J Pept Sci 2012;18(11):685-690; doi: 10.1002/psc.2455). Foundational paper for the "GHK without copper still does meaningful things" hypothesis.
- Antioxidant activity in living cells (Cebrián-Torrejón 2018) — The peptide reduces oxidative stress in cultured cells via direct quenching of hydroxyl and peroxyl radicals, independent of copper coordination (PMC6055086). Provides a clear mechanistic basis for one copper-independent therapeutic action.
- 4-HNE / acrolein sequestration (Beretta 2007, 2008) — The tripeptide's histidine residue directly conjugates with reactive lipid-peroxidation byproducts. The reaction proceeds without copper and is comparable to carnosine's aldehyde-scavenging activity (Chem Res Toxicol 2007;20(9):1309-1314; J Pharm Biomed Anal 2008;47(3):596-602).
- Gene-expression modulation (Pickart and Margolina reviews) — Microarray analyses of GHK-treated cells show broad modulation of human gene sets toward a "younger" expression profile. Pickart 2014, 2015, and 2018 reviews summarize the gene-expression data. Some gene-expression changes are copper-dependent and some are not; the sponsor of this work is Pickart's own research program, which is an important methodological context.
- Anti-cancer gene-expression signature (Pickart 2014, J Anal Oncol) — Reported that GHK induces pro-apoptotic caspase, growth-regulatory, and DNA-repair gene expression in cultured cells. Whether the copper-free form specifically replicates every gene-level effect of GHK-Cu has not been dissected.
- Russian CNS literature (Bobyntsev group) — Multiple rodent studies show that parenteral GHK produces anxiolytic, neurotransmitter-modulatory, and cognitive effects. Sequence specificity via D-amino-acid substitutions argues that the effect is peptide-receptor-mediated rather than a copper-delivery artefact. Western replication is thin, and the Russian literature is heterogeneous in methodology.
- Hair-follicle stimulation (largely GHK-Cu) — Cultured hair-follicle stimulation has been reported for both GHK and GHK-Cu. Whether copper-free GHK retains the full hair-growth signal in human use has not been tested in a controlled trial.
- Cosmetic ingredient evidence (overwhelmingly GHK-Cu) — Placebo-controlled topical cosmetic trials (Abdulghani 1998; Leyden 2002; subsequent cosmeceutical studies) use the copper-bound form. These do not directly transfer to copper-free GHK product claims.
- What is absent — No published human clinical trial of injected copper-free GHK. No published head-to-head efficacy comparison of GHK vs GHK-Cu in matched human applications. No formal human pharmacokinetic data for either form.
Research Limitation — Most Evidence Is on the Copper Form
The vast majority of GHK-family research uses the copper-bound form. Vendor marketing of copper-free GHK as a "research peptide" routinely cites GHK-Cu evidence as if it applied to the apopeptide. It does not, except in the specific cases where a study demonstrated copper-independent activity (Choi 2012 stem-cell work, the antioxidant literature, and the aldehyde-sequestration chemistry). Transfer of broad GHK-Cu claims to the copper-free form is not scientifically justified.
Human Data
There is no published clinical trial of injected or systemically dosed copper-free GHK in humans. The published human evidence base for the GHK family sits almost entirely on topical GHK-Cu cosmetic studies, none of which directly apply to parenteral copper-free GHK use.
- No registered trial of copper-free GHK — A search of ClinicalTrials.gov for "copper-free GHK," "free GHK," or "apo-GHK" returns no registered trials as of April 2026.
- No published human PK data — Neither the copper-free nor copper-bound form has been formally characterized for human pharmacokinetics after parenteral administration in the peer-reviewed literature. Plasma half-life is extrapolated from rodent data.
- Topical GHK-Cu cosmetic evidence (related, not directly transferable) — Multiple placebo-controlled 12-week facial cosmetic studies of topical GHK-Cu cream report improvements in collagen density, skin thickness, firmness, and fine-line reduction. These studies used the copper-bound form.
- Topical GHK Basic cosmetic formulations — Some commercial cosmetic serums use copper-free GHK (often listed as "Tripeptide-1" on INCI labels, distinct from "Copper tripeptide-1"). Controlled efficacy data on these specific formulations is limited and product-specific.
- Anecdotal SubQ and oral community use — Forum and practitioner reports describe SubQ injection of copper-free GHK (typically for hair or general anti-aging). These are uncontrolled, selection-biased, and frequently confounded by concurrent GHK-Cu, other peptides, and standard skincare.
- Practical implication — Anyone using copper-free GHK by injection is operating entirely outside the published human evidence base. The bar for clinician supervision and individual risk assessment is correspondingly higher.
Dosing from the Literature
No human dose-finding study has been performed for copper-free GHK. The ranges below are either cosmetic-formulation standards or extrapolations from GHK-Cu protocols. No FDA-approved dose exists.
| Route | Dose / Concentration | Frequency | Notes |
|---|
| Topical (cosmetic serum) | 0.1–2% peptide in formulation | 1–2x daily | Standard matrikine concentration range. Compatible with high-concentration ascorbic acid and retinoids where GHK-Cu is not. |
| Topical (professional / intensive) | 2–5% | Once daily | Higher-concentration leave-on products. Most topical evidence uses GHK-Cu. |
| Subcutaneous (community) | 1–3 mg | Once daily | Extrapolated from GHK-Cu community protocols. No copper-free-specific dose-response data. |
| Oral / sublingual (community) | 1–3 mg | Once daily | Oral bioavailability is poor (tripeptide is degraded by gastric and intestinal proteases). Inferential only. |
| Cycle length (community) | 4–12 weeks | — | Inherited from GHK-Cu protocols. No copper-free-specific tachyphylaxis or cycling data. |
Dosing Disclaimer
Copper-free GHK has never been formally dose-finding-studied in humans for any indication other than topical cosmetic formulation. Whether the copper-free form has different optimal dosing, half-life, or route preference than the copper-bound form has not been established. Anyone considering parenteral use should work with a licensed clinician.
Reconstitution & Storage
Copper-free GHK is supplied as a lyophilized powder, typically in 50 mg or 100 mg vials. Unlike GHK-Cu — which is blue-to-turquoise from the copper coordination — copper-free GHK is a colorless to off-white powder that reconstitutes to a clear, colorless solution.
| Vial Size | BAC Water | Concentration | 1 mg Dose | 2 mg Dose |
|---|
| 50 mg | 2 mL | 25 mg/mL | 4 units (0.04 mL) | 8 units (0.08 mL) |
| 100 mg | 2 mL | 50 mg/mL | 2 units (0.02 mL) | 4 units (0.04 mL) |
- Visual identity check — A reconstituted solution that turns blue or turquoise indicates copper coordination (i.e., the vial is GHK-Cu, not copper-free GHK). A colorless solution is consistent with the apopeptide. This is one of the simpler at-home identity checks for this class.
- Reconstitution — Bacteriostatic water injected slowly down the inside wall of the vial at 45°. Swirl gently — never shake.
- Storage — Lyophilized powder stable at room temperature for 12+ months out of light; refrigerated (2–8°C) for longer-term storage. Reconstituted solution refrigerated and used within 28 days.
- In-vivo copper coordination is inevitable — Once injected, copper-free GHK will encounter and bind some endogenous Cu²⁺ in serum and tissue. The product is "copper-free" pre-administration, not in the body.
- Topical formulation pairing — Copper-free GHK is compatible with high-concentration ascorbic acid serums and with retinoid formulations that destabilize the GHK-Cu complex. This is one of the concrete cosmetic-formulation advantages of the apopeptide.
→ Use the Kalios Dosing Calculator for exact syringe units
Side Effects & Risks
Important
Share this with your clinician before combining GHK Basic with penicillamine, trientine, or chronic high-dose zinc — the copper-sequestration chemistry becomes clinically relevant in copper-modulating regimens.
Copper-free GHK has no published human parenteral safety data specific to the apopeptide. The inferred risk profile draws from the GHK-Cu topical record plus the specific copper-sequestration considerations.
- Generally well-tolerated in topical cosmetic use — The GHK class has been used in topical cosmetic preparations at scale for >25 years with a favorable safety record. Skin irritation in sensitive users is the most commonly reported issue.
- Injection-site reactions (community parenteral use) — Mild local erythema, transient itching, or minor swelling are the most common community-reported issues. Generally resolve within hours.
- Theoretical copper-depletion concern at high doses — Because copper-free GHK binds endogenous Cu²⁺ in vivo, very high cumulative doses could theoretically deplete labile copper pools. Clinical significance at typical community doses is likely low but is unquantified. Dietary copper adequacy (RDA 900 mcg/day) is a reasonable foundational check.
- Interactions with copper-modulating drugs — Penicillamine and trientine (used for Wilson's disease) are explicit copper chelators; combining with copper-binding GHK is a meaningful interaction that warrants medical supervision. Zinc supplementation >40 mg/day chronically depletes copper through competition at intestinal transporters and could compound a GHK-driven copper-sequestration effect.
- Theoretical pro-angiogenic / regeneration concern — The GHK family modulates regenerative pathways. Like other tissue-repair peptides, this raises a theoretical concern about promoting growth in existing tumors or precancerous tissue. Pickart and colleagues have also published anti-cancer gene-expression findings, so the net in-vivo effect is ambiguous. Age-appropriate cancer screening before chronic systemic use is reasonable.
- WADA status — The GHK class is not specifically named on the WADA Prohibited List as of 2026. GHK-Cu has been informally discussed as a candidate for evaluation under S0 (non-approved substances) for tested athletes. The copper-free form by analogy would be evaluated similarly. Athletes should not use without explicit federation guidance.
- Sourcing risk — identity verification — The practical risk unique to this compound is buying GHK-Cu mislabeled as copper-free GHK, or vice versa. Independent COA (HPLC + mass spec) plus the visual color check (blue vs colorless after reconstitution) are the practical floor.
- Pregnancy / lactation — Insufficient data; avoid.
- Long-term safety unknown — Zero long-term human safety data exist for parenteral GHK in either form.
Bloodwork & Monitoring
No formal monitoring guideline exists for copper-free GHK. Conservative monitoring mirrors GHK-Cu protocols with attention to copper homeostasis.
- Independent vendor COA review — Mass-spec confirmation that the product is copper-free GHK (and not GHK-Cu mislabeled) is the most important pre-use check.
- Serum copper and ceruloplasmin — Baseline and at 8–12 weeks. Particularly relevant for users on extended high-dose parenteral protocols of the copper-free form given its endogenous copper-binding behavior.
- Baseline CMP and CBC — Liver, kidney, and hematological function before starting any parenteral peptide protocol; repeat at 8 weeks.
- Iron and ferritin — Copper, iron, and zinc share absorption and trafficking pathways. Suboptimal iron status can emerge during copper-modifying interventions.
- Cancer screening (age-appropriate) — Given the broad regenerative gene-expression signature of the GHK family, age-appropriate screening before initiating chronic use.
- Skin / hair photo documentation — For cosmetic / dermatological endpoints, standardized photographs at 0, 6, and 12 weeks are more reliable than subjective recall.
- Mood / sleep tracking — Given the Bobyntsev rodent anxiolytic literature, subjective mood and sleep changes during a cycle are reasonable endpoints to track.
Commonly Stacked With
The natural comparator and the more evidence-backed alternative. Users sometimes sequentially trial copper-free GHK and GHK-Cu to compare response. Concurrent stacking is uncommon and largely redundant since both forms converge in vivo after copper coordination.
Topical retinoid (tretinoin, retinaldehyde, retinol)
The single most evidence-backed topical anti-aging intervention. Copper-free GHK is one of the few peptides that formulates cleanly in the same product as high-concentration retinoids, where GHK-Cu would be destabilized. For users targeting skin quality, a topical retinoid plus dermatologist-grade sun protection is the foundation; GHK layers on top.
Vitamin C (topical ascorbic acid)
Cofactor for collagen synthesis. Copper-free GHK tolerates ascorbic acid formulations, which is one of the main practical arguments for using the apopeptide over GHK-Cu in a combination serum.
A different matrikine peptide (palmitoyl-pentapeptide-4) that stimulates fibroblast collagen synthesis. Used together in cosmetic formulations on the logic that different matrikines engage complementary fibroblast signaling pathways.
L-carnosine (oral)
Dipeptide with overlapping aldehyde-sequestration chemistry (same histidine-mediated reactivity toward 4-HNE and acrolein). Much cheaper, oral, decades of supplement use. For users whose goal is antioxidant / anti-aging support rather than skin-specific cosmetics, carnosine is the more evidence-backed option.
→ Check compound compatibility in the Stack Builder
Regulatory Status
Current Status — April 2026
Copper-free GHK (Gly-His-Lys tripeptide) is not FDA-approved for any therapeutic indication. As a peptide, it is research-only for parenteral or systemic use. Topical use as a cosmetic ingredient is the dominant legitimate route: the copper-bound form carries the INCI designation "Copper tripeptide-1" and the copper-free form is typically labeled "Tripeptide-1" on cosmetic ingredient lists.
Parent GHK-Cu appears on FDA's compounding bulk-substance evaluation lists, with its Category designation having shifted across recent years. On February 27, 2026, HHS Secretary Robert F. Kennedy Jr. publicly announced an intention to reclassify approximately 14 of the 19 Category 2 peptides — GHK-Cu among them — back to Category 1, which would make them available through licensed compounding pharmacies with a prescription. As of April 2026, the FDA has not published a formal update and the Pharmacy Compounding Advisory Committee (PCAC) has not completed review.
The copper-free GHK form has not been specifically named in either the Category 2 list or the RFK reclassification announcement — likely because regulatory attention focuses on the well-characterized copper-bound form. If GHK-Cu is reclassified to Category 1, it is unresolved whether copper-free GHK would automatically receive the same status; the two are technically different chemical entities and each would, in principle, require its own bulk-substance evaluation.
WADA: The GHK family is not specifically named on the Prohibited List. Athletes should consult their sport-specific federation before any use; the compound does not currently have a clean fit in any named S-class but could plausibly be evaluated under broader categories.
Cost & Access
Copper-free GHK is not approved for human use as a parenteral peptide therapeutic. It is available in two legitimate channels: (1) as an ingredient in topical cosmetic products sold over the counter without prescription, typically at peptide concentrations of 0.1–2% in serums and creams; and (2) through research-chemical suppliers for laboratory research purposes only, supplied as lyophilized powder in 50 mg or 100 mg vials.
U.S. compounding pharmacies cannot legally compound copper-free GHK for parenteral use under current FDA bulk-substance rules — the apopeptide has not been specifically named on any compounding-pathway list. If the parent GHK-Cu is reclassified to Category 1 under HHS Secretary Robert F. Kennedy Jr.'s February 2026 announcement, it remains unclear whether copper-free GHK would automatically follow, since each form would, in principle, require its own PCAC evaluation.
Cosmetic topical products containing copper-free GHK are widely available in consumer skincare; the research-chemical channel is the standard route for parenteral research use. Kalios does not sell compounds.
Access and regulatory status as of April 2026. Actual availability varies by jurisdiction, channel, and prescription status. Kalios does not sell compounds.
Related Compounds
GHK-family peptides and copper-tripeptide cousins:
Fragment of the GHK-Cu molecule studied for its role in gene expression and copper delivery.
Alanine-Histidine-Lysine copper peptide. Used primarily in hair-follicle activation and topical scalp formulations.
Palmitoyl-GHK (palmitoyl tripeptide-1). Lipophilic cosmetic version of GHK for topical anti-aging formulations.
Palmitoyl tetrapeptide-7. Anti-inflammatory cosmetic peptide that reduces interleukin-6 in aging skin.
Key References
- Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nat New Biol. 1973;243(124):85-87. PMID: 4351857. (Original isolation of GHK from human plasma.)
- Maquart FX, Pickart L, Laurent M, Gillery P, Monboisse JC, Borel JP. Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu²⁺. FEBS Lett. 1988;238(2):343-346. PMID: 3169264. (Foundational collagen-stimulation paper — copper-bound form.)
- Choi HR, Kang YA, Ryoo SJ, Shin JW, Na JI, Huh CH, Park KC. Stem cell recovering effect of copper-free GHK in skin. J Pept Sci. 2012;18(11):685-690. doi:10.1002/psc.2455. (Key paper for copper-free GHK: stem-cell preservation in human skin equivalents without copper coordination.)
- Pickart L, Vasquez-Soltero JM, Margolina A. The human tripeptide GHK-Cu in prevention of oxidative stress and degenerative conditions of aging. Oxid Med Cell Longev. 2012;2012:324832. PMID: 22666521.
- Pickart L, Vasquez-Soltero JM, Margolina A. GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. Biomed Res Int. 2015;2015:648108. PMID: 26236730.
- Pickart L, Margolina A. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. Int J Mol Sci. 2018;19(7):1987. PMID: 29986520. (Comprehensive modern review; notes copper-dependent vs copper-independent activities.)
- Pickart L, Vasquez-Soltero JM, Pickart FD, Majnarich J. GHK, the Human Skin Remodeling Peptide, Induces Anti-Cancer Expression of Numerous Caspase, Growth Regulatory, and DNA Repair Genes. J Anal Oncol. 2014;3(2):79-87.
- Beretta G, Aldini G, Facino RM, Russell RM, Krinsky NI, Yeum KJ. Glycyl-histidyl-lysine (GHK) is a quencher of α,β-4-Hydroxy-trans-2-nonenal: a comparison with carnosine. Insights into the mechanism of reaction by ESI-MS, ¹H NMR, and computational techniques. Chem Res Toxicol. 2007;20(9):1309-1314. doi:10.1021/tx700185s. (Copper-independent aldehyde-sequestration chemistry.)
- Beretta G, Arlandini E, Artali R, Anton JM, Maffei Facino R. Acrolein sequestering ability of the endogenous tripeptide glycyl-histidyl-lysine (GHK): characterization of conjugation products by ESI-MSn and theoretical calculations. J Pharm Biomed Anal. 2008;47(3):596-602.
- Trapaidze A, Hureau C, Bal W, Winterhalter M, Faller P. Thermodynamic study of Cu²⁺ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine. J Biol Inorg Chem. 2012;17(1):37-47. PMID: 21748269. (Quantifies the very high copper-binding affinity that drives in-vivo coordination after administration.)
- Pickart L, Freedman JH, Loker WJ, Peisach J, Perkins CM, Stenkamp RE, Weinstein B. Growth-modulating plasma tripeptide may function by facilitating copper uptake into cells. Nature. 1980;288(5792):715-717. PMID: 7432330.
- Pickart L, Vasquez-Soltero JM, Margolina A. The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline. Brain Sci. 2017;7(2):20. PMID: 28212278.
- Hostynek JJ, Dreher F, Maibach HI. Human skin penetration of a copper tripeptide in vitro as a function of skin layer. Inflamm Res. 2011;60(1):79-86. PMID: 20835751. (Topical penetration data — relevant to cosmetic copper-free formulations.)
- Pollard JD, Quan S, Kang T, Koch RJ. Effects of copper tripeptide on the growth and expression of growth factors by normal and irradiated fibroblasts. Arch Facial Plast Surg. 2005;7(1):27-31. PMID: 15655171.
- Gruchlik A, Jurzak M, Chodurek E, Dzierzewicz Z. Effect of Gly-Gly-His, Gly-His-Lys and their copper complexes on TNF-alpha-dependent IL-6 secretion in normal human dermal fibroblasts. Acta Pol Pharm. 2012;69(6):1303-1306. PMID: 23285693.
- FDA. Bulk Drug Substances Nominated for Use in Compounding — 503A and 503B Categories. FDA.gov. Updated 2025-2026.
- WADA Prohibited List 2026. World Anti-Doping Agency. wada-ama.org.
Last updated: April 2026 | Profile authored by Kalios Peptides research team