PepsRadar · Comparison · AI-assisted, written from the checked facts on each profile · Content updated (how dates work) · Not reviewed by a medical professional
The short answer
Both are copper peptides: related, but different molecules. GHK-Cu is a common skin-care ingredient whose selected studies are animal and lab work plus one small randomized skin-care trial (13 people) that found no objective benefit; AHK-Cu has been studied only in donated hair follicles and cultured cells. Neither is an FDA-approved drug.
Key differences
Different building blocks: GHK-Cu pairs copper with glycine-histidine-lysine, AHK-Cu with alanine-histidine-lysine.
GHK-Cu: the one randomized trial we found indexed in PubMed showed no objective improvement in wrinkles or redness over its comparison; most of its support comes from cell and animal work.
AHK-Cu: a 2007 laboratory study found very low concentrations lengthened cultured human hair follicles. No study in people has been published, including skin irritation or allergy testing.
GHK-Cu is in FDA’s compounding Category 1, so pharmacies may compound it while FDA reviews it, but FDA has flagged injectable GHK-Cu for immune-reaction and impurity risks.
GHK-Cu combines a short peptide with copper. It is discussed in topical skin care and tissue-remodeling research, which should be separated from injection claims.
AHK-Cu is a copper complex of the tripeptide alanine-histidine-lysine. It is related to GHK-Cu but is a different molecule. Its featured evidence uses donated human hair follicles and cultured cells, not people using a product.
Human evidence
1 randomized trial
No human studies in our sources; animal and lab studies only
Human safety data
Very limited. GHK-Cu is a copper peptide used in skin products. Small skin studies exist, but FDA flagged injectable GHK-Cu for immune-reaction and impurity risks, with limited human data.
None. AHK-Cu is a copper-peptide cosmetic ingredient studied only in donated hair follicles and cultured cells. No human safety studies, including skin irritation or allergy testing, have been published.
Boxed warning
No FDA label to carry one
No FDA label to carry one
Serious risks
FDA: injectable GHK-Cu may cause immune reactions (immunogenicity) from aggregation and peptide impurities
None listed
Conditions flagged
None flagged, because there is too little human safety data to assess
None flagged, because there is too little human safety data to assess
Each row comes from the GHK-Cu and AHK-Cu profiles, where every fact links to its source. “Conditions flagged” lists the health conditions each profile’s Risks & interactions section mentions.
The human studies
GHK-Cu
Laser-resurfacing skin study (2006)
Small human randomized trial (topical) · 13 adults who completed the study after CO2 laser resurfacing around the mouth.
No significant difference in redness resolution, wrinkles or overall skin quality on objective measures; patients using GHK-Cu reported higher satisfaction on a questionnaire.
Limitation: Thirteen people, a cosmetic skin product and a mostly negative objective result. It says nothing about injected GHK-Cu, which is what FDA flagged.
No human studies in our sources. See the AHK-Cu profile for the animal and lab research.
Results from different trials are not a head-to-head comparison: the people, preparations, durations and measures differ.
Bottom line
A cosmetic ingredient on the skin and an injected research product are different questions, and neither peptide has human evidence for the injectable vials sold online.
PepsRadar does not give doses or usage instructions, and this page is not medical advice. For a prescription medicine, talk to your prescriber or pharmacist.
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