Category
Skin & Cosmetic
Peptides applied topically or studied in dermal models for collagen synthesis, wound repair, antioxidant signaling, and skin structure maintenance. GHK-Cu is the most extensively characterized compound in this category, with decades of peer-reviewed research.
12 peptides in this category
What do peptides do in skincare?
Peptides in skincare work by mimicking or triggering the signaling sequences the skin uses to regulate collagen production, wound repair, and cellular renewal. GHK-Cu, a copper-binding peptide naturally found in young skin, stimulates fibroblast activity and collagen synthesis while remodeling existing matrix through metalloproteinase activation. Signal peptides like Matrixyl work by mimicking procollagen fragments that signal the skin to produce more collagen. Neurotransmitter-inhibiting peptides like Argireline reduce muscle contraction intensity at injection-free doses. The limiting factor for most topical peptides is skin penetration through the outer epidermal barrier.
Skin aging involves loss of collagen density (especially types I and III), reduced glycosaminoglycan content, decreased fibroblast activity, and impaired wound healing response. Several classes of peptides have been developed or identified to address these changes at the cellular level. GHK-Cu (glycine-histidine-lysine with a copper ion) is a naturally occurring peptide found in human plasma that acts as a potent tissue remodeling signal. It promotes fibroblast proliferation, stimulates collagen and elastin synthesis, activates matrix metalloproteinases for collagen remodeling, and has antioxidant and anti-inflammatory properties. Plasma GHK-Cu levels decline substantially with age, from around 200 ng/mL at age 20 to near undetectable levels by age 60.
Beyond copper peptides, the skincare peptide category includes signal peptides (like Matrixyl/Palmitoyl pentapeptide-4, which mimics procollagen fragments to stimulate synthesis), carrier peptides, and neurotransmitter-inhibiting sequences (like Argireline, an analog of SNAP-25 that reduces acetylcholine release at the neuromuscular junction). The mechanisms are real, though penetration through the stratum corneum remains a limiting factor for many — which is why delivery system research and peptide lipidation are active areas in cosmetic science.
Compounds
Peptides in this category
Argireline
PreclinicalAcetyl Hexapeptide-3 · Acetyl Hexapeptide-8
Argireline is a synthetic hexapeptide derived from the N-terminal sequence of SNAP-25 protein, a key component of the SNARE complex that mediates acetylcholine release at neuromuscular junctions. It competitively inhibits neurotransmitter vesicle docking, reducing muscle contraction and expression-line formation. Often called "topical Botox," clinical studies show measurable reductions in peri-orbital wrinkle depth with consistent use.
Collagen Peptides
PreclinicalHydrolyzed Collagen · Collagen Hydrolysate
Hydrolyzed collagen peptides are short-chain amino acid sequences (2–20 amino acids) produced by enzymatic hydrolysis of collagen. Research demonstrates that specific collagen dipeptides and tripeptides (Pro-Hyp, Hyp-Gly) are absorbed intact, reach fibroblasts in skin and joints, and stimulate collagen and hyaluronic acid synthesis. Meta-analyses support effects on skin elasticity, wrinkle depth, joint pain, and muscle mass when combined with resistance exercise.
GHK-Cu
PreclinicalCopper Peptide GHK · Glycyl-L-histidyl-L-lysine copper
GHK-Cu is a naturally occurring copper-binding tripeptide found in human plasma, saliva, and urine. Research demonstrates it stimulates collagen, elastin, and glycosaminoglycan synthesis, promotes wound healing, reduces inflammation, and activates protective antioxidant genes. Plasma levels decline with age, making it a significant anti-aging research target.
C₁₄H₂₄CuN₆O₄ · 340.84 Da (free ligand)
Leuphasyl
PreclinicalPentapeptide-18
Leuphasyl is a pentapeptide that acts as an enkephalin analog, binding to δ-opioid receptors on muscle cells and neuronal cells to modulate acetylcholine release and reduce muscle contraction. Often combined with Argireline in cosmetic formulations for a synergistic anti-wrinkle effect, studies show the combination outperforms either compound alone in reducing crow's feet and forehead lines.
Melanotan I
ApprovedAfamelanotide · Scenesse
Melanotan I (afamelanotide) is a linear synthetic α-MSH analog with higher selectivity for MC1R than MT-II. FDA-approved as Scenesse for erythropoietic protoporphyria (EPP), where it reduces phototoxic pain by enhancing melanin production and UV protection. Research explores broader applications in vitiligo, polymorphous light eruption, and other photosensitive disorders.
Melanotan II
PreclinicalMT-II · MT2
Melanotan II is a cyclic synthetic analog of α-MSH that non-selectively activates melanocortin receptors (MC1R–MC5R). It induces skin tanning (via MC1R), erectile function (via MC4R), and sexual arousal while also suppressing appetite. It was the precursor compound from which PT-141 was developed. Research continues despite regulatory concerns due to its broad receptor activity profile.
Palmitoyl Pentapeptide-4
PreclinicalMatrixyl · Pal-KTTKS
Palmitoyl Pentapeptide-4 (Matrixyl) is a lipopeptide widely used in cosmetic anti-aging formulations. It is derived from the procollagen type I sequence and acts as a matrikine, signaling skin cells to produce collagen, elastin, fibronectin, and hyaluronic acid. Clinical studies demonstrate measurable reduction in wrinkle depth and improved skin elasticity with topical application.
Palmitoyl Tripeptide-1
PreclinicalPal-GHK · Matrixyl component
Palmitoyl Tripeptide-1 is a lipopeptide created by palmitoylating GHK (glycyl-histidyl-lysine), the same sequence as GHK-Cu without copper. The palmitoyl group enhances skin penetration, while the GHK sequence signals fibroblasts to upregulate collagen, elastin, and hyaluronic acid synthesis. It is a primary active ingredient in Matrixyl formulations and widely used in anti-aging cosmetics with clinical data supporting wrinkle reduction.
RGD Peptides
PreclinicalArg-Gly-Asp · Integrin-binding peptide
RGD (Arg-Gly-Asp) is a tripeptide sequence found in many extracellular matrix proteins (fibronectin, vitronectin, collagen) that serves as the primary recognition motif for integrin receptors. RGD-containing peptides and scaffolds are extensively used in biomaterials research to promote cell adhesion, migration, and proliferation for tissue engineering, wound healing, and regenerative medicine applications.
SNAP-8
PreclinicalAcetyl Octapeptide-3
SNAP-8 is an extended version of Argireline (an octapeptide vs hexapeptide), designed with enhanced SNARE-inhibiting potency. By more completely blocking the formation of the SNARE complex, it more effectively reduces muscle contraction at treated sites. Cosmetic research shows superior wrinkle reduction efficacy compared to Argireline at equivalent concentrations, particularly in forehead lines.
Syn-Ake
PreclinicalDipeptide Diaminobutyroyl Benzylamide Diacetate
Syn-Ake is a synthetic dipeptide that mimics the mechanism of waglerin-1, a peptide found in Temple Viper venom, by antagonizing muscular nicotinic acetylcholine receptors and reducing muscle contraction. Applied topically, it reduces the depth of expression lines by temporarily relaxing facial muscles. It has become a common high-end cosmetic ingredient positioned as a non-injectable alternative to botulinum toxin.
α-MSH
PreclinicalAlpha-Melanocyte-Stimulating Hormone · α-Melanotropin
α-MSH is an endogenous 13-amino-acid peptide derived from POMC (pro-opiomelanocortin). It activates MC1R to stimulate melanin production in skin, MC4R to suppress appetite and regulate energy expenditure, and MC3R/MC1R to exert potent anti-inflammatory effects. It is the parent compound from which many synthetic melanocortin analogs (Melanotan I, II, PT-141, KPV) were derived and remains a cornerstone of melanocortin pharmacology research.
Research applications
What researchers are studying
Collagen and elastin stimulation
GHK-Cu has been shown in fibroblast culture and human skin biopsy studies to increase type I collagen synthesis, fibronectin, and decorin while simultaneously stimulating the enzymes that remodel and cross-link new collagen. This dual effect — synthesis plus remodeling — is more physiologically complete than approaches that simply stimulate collagen production without improving matrix organization.
Wound healing acceleration
In partial-thickness wound models, GHK-Cu attracts macrophages and mast cells to the wound site, increases blood vessel formation, and reduces scarring versus untreated controls. These wound-healing properties informed its cosmetic applications: the same signaling that speeds surgical wound closure also improves the skin's ability to repair chronic low-level damage from UV, pollution, and mechanical stress.
Gene expression and anti-aging signaling
Microarray analyses of cells treated with GHK-Cu show broad changes in gene expression affecting DNA repair, antioxidant enzyme systems, and growth factor production. Studies suggest it resets fibroblast gene expression closer to a younger phenotype, which aligns with its observed effects on skin thickness, firmness, and reduction in fine line depth in human clinical trials.
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