WhatPeptide

GHK

GHK is the parent tripeptide that forms the copper-chelating complex GHK-Cu, studied for its own biological activities including gene expression modulation, tissue remodeling, and anti-inflammatory effects. It naturally declines with age and is found in plasma, saliva, and urine.

Moderate evidence Unregulated Cosmetic

Written by WhatPeptide Editorial Team · Last updated 2026-03-17

Half-life

Short; rapidly cleaved by tissue peptidases

Dosage range

1-5% in topical formulations; systemic exposure ranges not well established

Administration

Topical

Research level

Moderate

How GHK works

GHK modulates expression of over 4,000 human genes involved in tissue remodeling, antioxidant defense, and anti-inflammatory responses, even before copper chelation is considered. The free peptide activates pathways including TGF-beta signaling and metalloproteinase regulation relevant to collagen synthesis and dermal matrix remodeling. When complexed with copper, these effects are amplified through copper-dependent enzyme activation in wound healing and hair follicle biology.

Also known as: Glycyl-L-Histidyl-L-Lysine, Copper-free GHK, GHK tripeptide

Research relevance

Hair & Skin
Moderate relevance 65
Anti-Aging & Longevity
Moderate relevance 50
Recovery & Healing
Some relevance 40

Side effects & safety

Generally well tolerated topically Mild skin irritation possible

Contraindications

Known tripeptide hypersensitivity

Consult a healthcare provider before use if any of these apply to you.

Key studies

FAQ

What is GHK? +
GHK is the parent tripeptide that forms the copper-chelating complex GHK-Cu, studied for its own biological activities including gene expression modulation, tissue remodeling, and anti-inflammatory effects. It naturally declines with age and is found in plasma, saliva, and urine. Its mechanism of action is supported by moderate clinical and preclinical evidence.
What is GHK researched for? +
GHK has the strongest research relevance for Hair & Skin, Anti-Aging & Longevity, Recovery & Healing. Evidence is supported by moderate clinical and preclinical evidence.
What are the side effects of GHK? +
Reported side effects include Generally well tolerated topically, Mild skin irritation possible. Key contraindications: Known tripeptide hypersensitivity.
Is GHK FDA approved? +
GHK is not FDA-approved. It is available as a research compound or through compounding pharmacies in some jurisdictions.
How is GHK administered? +
GHK is typically administered via topical route. Researched dosage range: 1-5% in topical formulations; systemic exposure ranges not well established. Half-life: Short; rapidly cleaved by tissue peptidases.

Explore similar peptides

AHK-Cu

Preliminary evidence

Cosmetic

AHK-Cu is a copper-binding tripeptide studied for its ability to stimulate hair follicle proliferation and promote wound healing through copper-dependent enzymatic pathways. It is a less widely studied relative of GHK-Cu but shares overlapping mechanisms relevant to hair and skin biology.

GHK-Cu

Moderate evidence

Cosmetic

A naturally occurring copper-binding tripeptide widely studied in skin and hair biology and extracellular matrix remodeling. Note: FDA Category 2 applies to injectable routes only. Non-injectable administration (topical, nasal, oral) remains Category 1 (permitted for compounding).

Snap-8

Preliminary evidence

Cosmetic

Snap-8 is a synthetic octapeptide (acetyl octapeptide-3) studied as a topical cosmetic active for reducing the appearance of expression lines by targeting the SNARE protein complex involved in neuromuscular vesicle docking. It is marketed as a peptide alternative to botulinum toxin for cosmetic wrinkle reduction.