How GHK-Cu is analysed: HPLC purity, mass-spectrometry identity, copper content, degradation products, and how to read a certificate of analysis.
By the GHK-Cu Peptide editorial team · Last reviewed · Editorial review: pending
Short answer
GHK-Cu laboratory testing answers separate questions with separate methods. HPLC measures purity and can resolve degradation products [Badenhorst 2016]; mass spectrometry confirms which peptide and copper complexes are present [Mazurowska 2007]; ICP-based methods measure copper [Zajda 2024]. A purity percentage alone cannot show whether a sample is GHK or GHK-Cu, or which copper ratio it contains.
Purity versus identity
Purity is how much of what the method detects is the main component. Identity is whether that component is the molecule on the label. A sample can be 99% pure by HPLC and still be the wrong substance, the copper-free peptide, or a different copper ratio. Because PubChem holds a 1:1 record at 402.92 g/mol [PubChem], a 2:1 record at 742.3 g/mol[PubChem] and copper-free GHK at 340.38 g/mol [PubChem], a mass result needs to say which species was found.
Methods and what each can tell you
Analytical methods for GHK-Cu and what each measures
Copper measured is not copper bound. ICP methods report total copper. Studies of skin permeation, for example, measured copper crossing the skin, not intact peptide[Hostynek 2010]. Capillary electrophoresis coupled to ICP-MS/MS can separate species before detection [Zajda 2024].
Speciation depends on pH. Several Cu–GHK species exist across pH 3.5–10.6 [Lau 1981], and the dominant species changes at the transitions spectroscopy identifies[Freedman 1982]. A result is tied to the conditions of the measurement.
Degradation is measurable. Under basic and oxidative stress GHK-Cu hydrolyses, and HPLC-MS identified three degradants including histidine [Badenhorst 2016].
Biological samples are harder. In rat plasma, a validated HPLC method needed solid-phase extraction and derivatisation, and detected GHK down to 50 ng/mL [Endo 1997]. Palmitoyl-GHK has served as an internal standard for LC-MS/MS of cosmetic peptides [Chirita 2009].
HPLC purity is the share of the detected signal that belongs to the main peak under one method. It does not by itself confirm the identity of that peak, the copper content, the copper-to-peptide ratio, the counter-ion, water content or the net peptide amount.
How is GHK-Cu identity confirmed?
Mass spectrometry confirms the mass of the peptide and its copper complexes. Copper content is measured separately, for example by ICP-MS. Together with HPLC purity, these answer different questions.
Can a COA show whether a sample is GHK or GHK-Cu?
Only if it reports copper content or a mass that includes copper. A purity percentage alone cannot distinguish copper-free GHK from GHK-Cu.
References
Badenhorst T, Svirskis D, Wu Z (2016). Physicochemical characterization of native glycyl-l-histidyl-l-lysine tripeptide for wound healing and anti-aging: a preformulation study for dermal delivery. Pharm Dev Technol. PubMed 25384620 · doi:10.3109/10837450.2014.979944[Chemistry, grade D]
Endo T, Miyagi M, Ujiie A (1997). Simultaneous determination of glycyl-L-histidyl-L-lysine and its metabolite, L-histidyl-L-lysine, in rat plasma by high-performance liquid chromatography with post-column derivatization. J Chromatogr B Biomed Sci Appl. PubMed 9187381 · doi:10.1016/s0378-4347(96)00460-4[Chemistry, grade D]
Mazurowska L, Mojski M (2007). ESI-MS study of the mechanism of glycyl-l-histidyl-l-lysine-Cu(II) complex transport through model membrane of stratum corneum. Talanta. PubMed 19071668 · doi:10.1016/j.talanta.2006.11.034[Chemistry, grade D]
Chirita RI, Chaimbault P, Archambault JC et al. (2009). Development of a LC-MS/MS method to monitor palmitoyl peptides content in anti-wrinkle cosmetics. Anal Chim Acta. PubMed 19393372 · doi:10.1016/j.aca.2009.03.015[Chemistry, grade D]
Zajda J, Wadych E, Ogórek K et al. (2024). Novel Applications of CE-ICP-MS/MS: Monitoring of Antiaging GHK-Cu Cosmetic Component Encapsulation in Liposomes. Electrophoresis. PubMed 39451062 · doi:10.1002/elps.202400047[Chemistry, grade D]
Ogórek K, Mierzwa M, Drozd M et al. (2026). Characterization of copper tripeptide-loaded lipid carriers and their stability in complex cosmetic matrices. J Chromatogr A. PubMed 42887096 · doi:10.1016/j.chroma.2026.467540[Chemistry, grade D]
Hostynek JJ, Dreher F, Maibach HI (2010). Human skin retention and penetration of a copper tripeptide in vitro as function of skin layer towards anti-inflammatory therapy. Inflamm Res. PubMed 20703511 · doi:10.1007/s00011-010-0214-4[Ex vivo, grade D]
Lau SJ, Sarkar B (1981). The interaction of copper(II) and glycyl-L-histidyl-L-lysine, a growth-modulating tripeptide from plasma. Biochem J. PubMed 7340824 · doi:10.1042/bj1990649[Chemistry, grade D]
Freedman JH, Pickart L, Weinstein B et al. (1982). Structure of the Glycyl-L-histidyl-L-lysine--copper(II) complex in solution. Biochemistry. PubMed 6291585 · doi:10.1021/bi00262a004[Chemistry, grade D]
Hureau C, Eury H, Guillot R et al. (2011). X-ray and solution structures of Cu(II) GHK and Cu(II) DAHK complexes: influence on their redox properties. Chemistry. PubMed 21780203 · doi:10.1002/chem.201100751[Chemistry, grade D]
Mateescu DM, Gavrilescu DM, Mincioaga RI et al. (2026). GHK-Cu as a Bioactive Metallopeptide and Drug-Delivery Cargo: Coordination Chemistry, Formulation Science, Therapeutic Evidence, and a Translational Roadmap. Pharmaceutics. PubMed 42797253 · doi:10.3390/pharmaceutics18091077[Review, grade R]
PubChem, National Library of Medicine. glycyl-L-histidyl-L-lysine (CID 73587). Source[retrieved 2026-11-11]
PubChem, National Library of Medicine. Prezatide copper (CID 71587328). Source[retrieved 2026-11-11]
PubChem, National Library of Medicine. Bisprezatide copper (CID 9831891). Source[retrieved 2026-11-11]