Pal-AHK
A palmitoylated cosmeceutical tripeptide (Ala-His-Lys) studied for hair growth stimulation via dermal papilla cell proliferation and anti-apoptotic signaling, as well as collagen synthesis and skin rejuvenation.
What is Pal-AHK?
Pal-AHK is a synthetic lipopeptide consisting of the tripeptide alanine-histidine-lysine (AHK) conjugated to palmitic acid. Its molecular formula is C31H56N6O5 with a molecular weight of approximately 592.8 Da. The palmitoyl modification enhances lipophilicity, improving penetration through the skin's lipid-rich stratum corneum compared to the unmodified AHK sequence. While structurally related to Pal-GHK (Palmitoyl Tripeptide-1) — which uses glycine in place of alanine — Pal-AHK has a distinct research profile centered on hair follicle stimulation and dermal papilla cell survival rather than matrikine-driven collagen signaling. The AHK sequence also has affinity for copper ions, forming the AHK-Cu complex (Copper Tripeptide-3), which is the form used in most published in vitro research. Its INCI name is Palmitoyl Tripeptide-28, though it is also referenced under the older designation Palmitoyl Tripeptide-3.
Why People Talk About It
Hair growth stimulation and dermal papilla cell proliferation
PreliminaryAnti-apoptotic protection of hair follicle cells (Bcl-2/Bax modulation)
PreliminaryCollagen type I synthesis and skin anti-aging
PreliminaryVEGF upregulation and dermal microcirculation support
LimitedSkin pigmentation and tone improvement (cosmeceutical claims)
LimitedHow It Works
Pal-AHK works primarily by supporting hair follicle cells. In lab studies, the AHK sequence (in its copper-bound form) stimulated dermal papilla cells — the specialized cells at the base of hair follicles that control the growth cycle — to proliferate and survive longer. It does this by tipping the balance of survival proteins: increasing Bcl-2 (a pro-survival signal) and decreasing Bax (a pro-death signal), which reduces programmed cell death. It also boosts VEGF production, which promotes blood vessel formation and nutrient delivery to follicles and skin. Separately, AHK stimulates fibroblasts to produce more collagen type I, contributing to skin firmness. The palmitoyl modification helps the peptide penetrate the skin's outer lipid barrier when applied topically.
Common Questions
Safety Information
Common Side Effects
Cautions
- • Not FDA-approved as a drug — marketed as a cosmeceutical ingredient
- • Injectable use has not been studied in humans
- • Most published research used the copper-complexed form (AHK-Cu), not the palmitoylated form
- • Quality and concentration vary across cosmeceutical and research-grade sources
- • No established dosing guidelines for any route of administration
What We Don't Know
Systemic safety has not been evaluated. Long-term topical safety is inferred from general cosmeceutical use but not supported by formal clinical safety trials. Whether the palmitoylated form retains the same biological activity as the copper-complexed form in vivo has not been directly confirmed. The effects on melanogenesis and hair pigmentation lack published mechanistic data.
Published Research
5 studiesCosmetic peptides in skin anti-ageing: matrikines, copper carrier peptides, neurotransmitter-inhibiting peptides, and other less discussed peptides
Review covering cosmeceutical peptide classes including copper carrier peptides and matrikines, providing context for AHK-related peptides within the broader anti-aging peptide landscape.
Topical and nutricosmetic products for healthy hair and dermal antiaging using "dual-acting" (2 for 1) plant-based peptides, hormones, and cannabinoids
Sadgrove et al. (2021) review discussing AHK among dual-acting cosmeceutical peptides for hair and skin, contextualizing its TGF-beta modulation and potential for combined dermal and follicular benefits.
Safety Assessment of Tripeptide-1, Hexapeptide-12, Their Metal Salts and Fatty Acyl Derivatives, and Palmitoyl Tetrapeptide-7 as Used in Cosmetics
CIR safety assessment covering tripeptide-1 and related fatty acyl derivatives used in cosmetics, providing regulatory context for palmitoylated tripeptide ingredients.
The effect of tripeptide-copper complex on human hair growth in vitro
Foundational study by Pyo et al. (2007) demonstrating AHK-Cu stimulates human hair follicle elongation ex vivo and dermal papilla cell proliferation in vitro, with anti-apoptotic effects via Bcl-2/Bax modulation and reduced caspase-3/PARP cleavage.
Usage of Synthetic Peptides in Cosmetics for Sensitive Skin
Comprehensive review of synthetic peptides in cosmeceuticals including palmitoyl tripeptides, covering mechanisms, skin penetration enhancement via lipidation, and safety profiles.
Related Peptides
Palmitoyl Tripeptide-1
ModerateBeginnerA collagen-boosting cosmetic peptide that mimics the body's wound-healing signal to stimulate collagen and elastin production in the skin.
GHK-Cu
ModerateBeginnerA naturally occurring copper-binding peptide with extensive research on skin remodeling, wound healing, and anti-aging.
Matrixyl
ModerateBeginnerA collagen-stimulating cosmetic peptide that signals skin to produce more collagen and extracellular matrix proteins.
Rigin
PreliminaryBeginnerAn immunomodulatory tetrapeptide derived from human IgG, used in cosmeceuticals as Palmitoyl Tetrapeptide-7 to suppress skin inflammation (IL-6) and support anti-aging skin repair.
Argireline
ModerateBeginnerA cosmetic peptide that reduces wrinkles by inhibiting neurotransmitter release at the neuromuscular junction, often called 'topical Botox.'
Quick Facts
- Class
- Cosmeceutical Peptide
- Evidence
- Preliminary
- Safety
- Limited Data
- Updated
- Apr 2026
- Citations
- 5PubMed
Also known as
Tags
Related Goals
Evidence Score
Clinical Trials
View Clinical TrialsLinks to ClinicalTrials.gov for reference. Listing does not imply endorsement.