Skin research
Collagen, copper, and cosmetic repair. Below is the published literature for each compound in this area — 76 studies in total, 50 of them published since 2023, every one linked to its source record.
- SkinPreclinical only
AHK-Cu
AHK-Cu (L-alanyl-L-histidyl-L-lysine copper(II), INCI-adjacent to the cosmetic ingredient Tripeptide-3) is a structural analogue of GHK-Cu in which glycine is replaced by alanine. The directly published evidence base is very small: a single ex vivo and cell-culture study of human hair follicles and dermal papilla cells is the principal dermatological source, supplemented by a topical delivery study of Tripeptide-3 for facial sebum and by work on a vitamin C-conjugated AHK derivative in a non-cutaneous model. Most claims made for AHK-Cu are extrapolated from the wider copper-tripeptide literature rather than from AHK-specific data.
- Studies
- 10
- Since 2023
- 6
- Newest
- 2026
- SkinEarly clinical
GHK-Cu
GHK (glycyl-L-histidyl-L-lysine) is an endogenous human plasma tripeptide that binds copper(II) with high affinity. In cell culture it increases fibroblast collagen and glycosaminoglycan synthesis at picomolar to nanomolar concentrations, and gene-expression work reports broad modulation of extracellular-matrix, antioxidant and inflammatory programmes. Human data are limited: most published work is in vitro or in animal models, and the small number of controlled human trials of topical GHK-Cu have produced mixed results, including two randomised trials that found no advantage over comparator or placebo.
- Studies
- 15
- Since 2023
- 10
- Newest
- 2026
- SkinClinical
Healthy Hair, Skin & Nails Blend
Biotin (vitamin B7) is an essential cofactor for five carboxylases, and frank biotin deficiency causes alopecia and dermatitis that resolve with repletion. In people without a deficiency, however, the evidence that supplemental biotin improves hair, skin or nail outcomes is weak: systematic and narrative reviews consistently find only a handful of small, biased or negative studies. High-dose biotin is also a recognised cause of clinically significant interference in streptavidin-biotin immunoassays, producing falsely raised or lowered results for thyroid, cardiac, hormone and other analytes. Other B vitamins have their own dermatological evidence base, with nicotinamide the best studied, showing benefit for keratinocyte-cancer chemoprevention in immunocompetent high-risk patients but no benefit in organ-transplant recipients.
- Studies
- 15
- Since 2023
- 12
- Newest
- 2026
- SkinPreclinical only
KLOW Blend
KLOW is a marketed combination of four peptides: BPC-157, TB-500 (a fragment-based thymosin beta-4 analogue), GHK-Cu and KPV. A systematic search of PubMed and Europe PMC returned no published study of this four-peptide blend in any model, and no pharmacokinetic, efficacy or safety data exist for the combination. The available literature is component-level: BPC-157 rests almost entirely on rodent work from a small number of laboratories with only two very small uncontrolled human pilot studies; thymosin beta-4 has two randomised phase 2 wound trials; KPV is supported by in vitro and animal anti-inflammatory work; and GHK-Cu is covered separately in this dataset. Only one published study examines any two of the components together.
- Studies
- 16
- Since 2023
- 10
- Newest
- 2026
- SkinApproved drug
Melanotan 2
Melanotan II and afamelanotide are synthetic analogues of alpha-melanocyte-stimulating hormone that act at melanocortin receptors to increase eumelanin synthesis. Afamelanotide (a selective, largely MC1R-directed analogue) is an approved medicine for erythropoietic protoporphyria supported by randomised placebo-controlled trials and post-authorisation safety cohorts, and has been trialled with narrowband UV-B in vitiligo. Melanotan II is a non-selective, unlicensed peptide sold illegally for tanning; it has never been through a completed efficacy or safety programme, and its published human literature consists almost entirely of adverse-event case reports, including eruptive and dysplastic naevi, melanoma and mucosal melanoma, priapism, renal infarction and systemic reactions.
- Studies
- 20
- Since 2023
- 12
- Newest
- 2026
Latest published research
A framework for the safety evaluation of peptides in cosmetics.
Current Research in Toxicology · review of historical cosmetic peptide safety evaluation plus a proposed six-tool bioinformatic framework
PubMed · 41953401Copper(II)-Tripeptide Complexes as Potential Skin Healing Agents: Synthesis, Characterization, and Wound Repair Ability.
ChemMedChem · synthesis and characterisation of copper(II)-tripeptide complexes with wound-repair assays
PubMed · 42047624Overview of Short Peptides for Hair Loss.
Biomedicines · narrative review of short peptides investigated for hair loss
PubMed · 42072405A Torilis japonica Extract-GHK-Cu Complex Attenuates Th2 Cytokines and Promotes Keratinocyte Recovery: A Potential Antioxidant Strategy for Atopic Dermatitis.
Antioxidants (Basel) · TNF-alpha/IFN-gamma-stimulated HaCaT keratinocyte model of atopic dermatitis
PubMed · 42510549Augmented Skin Beneficial Effects of Thermus Thermophilus and Bacillus Subtilis Mixed-Culture Ferment Extract by Tripeptide GHK-Cu.
Skin Research and Technology · in vitro (LPS-stimulated macrophages), ex vivo skin, plus human application testing
PubMed · 42573538Multi-Target Restoration of Dermal Elastic Fibers Through Elastin Upregulation, Elastase Suppression, and Scaffold Reinforcement.
Current Issues in Molecular Biology · human dermal fibroblast cultures; multi-ingredient comparison
PubMed · 42193036Peptide-enriched hydrogel formulation for sensitive and damaged skin: from design to application testing.
Scientific Reports · formulation development plus in vitro human skin cell assays and dermatological testing in human participants
PubMed · 42032121The GHK-Cu delays aging in Caenorhabditis elegans via coordinated regulation of mitochondrial function and activation of DAF-16/SKN-1 pathways.
Biogerontology · Caenorhabditis elegans lifespan and stress-resistance assays
PubMed · 42084774
For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition. Nothing on this page is medical advice.