GHK-Cu (Copper Peptide) vs Leuphasyl
A naturally occurring copper peptide that acts like a master switch for your body's repair systems—boosting collagen production, accelerating wound healing, and helping your skin rebuild itself from the inside out [1][4].
Enkephalin-mimetic cosmetic peptide that reduces expression wrinkles by modulating acetylcholine release at the neuromuscular junction, offering a Botox-like topical alternative.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
GHK-Cu (Copper Peptide)
0.1–0.1 %
Leuphasyl
5–5 %
Frequency
GHK-Cu (Copper Peptide)
Once or twice daily, topical
Leuphasyl
Once daily
Administration
GHK-Cu (Copper Peptide)
Subcutaneous injection
Leuphasyl
Topical application (serums, creams, ampoules)
Cycle length
GHK-Cu (Copper Peptide)
12 weeks, then ongoing
Leuphasyl
Ongoing/indefinite
Onset speed
GHK-Cu (Copper Peptide)
Moderate (1-2 weeks)
Leuphasyl
Slow (5+ weeks)
Evidence level
GHK-Cu (Copper Peptide)
Strong preclinical (extensive animal studies)
Leuphasyl
Moderate human trials (Phase 1-2)
Benefit ratings
Skin Rejuvenation
Wound Healing
Tissue Regeneration
Wrinkle Reduction
Skin Smoothing
Anti-Aging Prevention
Compound specifications
GHK-Cu (Copper Peptide)
Molecular formula
C14H23N6O4Cu
Molecular weight
403.93 g/mol
Half-life
Approximately 1 hour (plasma)
Bioavailability
High when injected subcutaneously; variable topically depending on formulation
CAS number
49557-75-7
Leuphasyl
Molecular formula
C29H39N5O7
Molecular weight
569.65 g/mol
Half-life
Topical application (local activity, systemic half-life not applicable)
Bioavailability
Limited (topical peptide; skin penetration challenged by hydrophilic nature and molecular size)
CAS number
64963-01-5
Dosing compared
GHK-Cu (Copper Peptide)
Topical
0.1% cream (roughly 1 mg/mL)
Once or twice daily to the treatment area · 12 weeks for visible results, then ongoing
This is the only GHK-Cu route with a controlled human trial behind it, and the trial was largely negative. Thirteen patients used a GHK-Cu aftercare regimen after CO2 laser resurfacing; blinded assessment found no significant improvement in redness, wrinkles or overall skin quality versus the control regimen, and only the patients' own rating separated (P = 0.04) [7]. Topical wound-healing evidence beyond that is animal — 24 rats with ischemic wounds, where the copper tripeptide gel reduced wound area faster than vehicle [4]. Concentration matters and is not standardised across products; the figures quoted for cosmetic creams come from industry reports rather than independent trials [1][2].
Subcutaneous
No established human dose
Not established · Not established
There are no human studies of injected GHK-Cu by any systemic route. The GHK-Cu studies registered on ClinicalTrials.gov are topical or transdermal [13]. The 1-2 mg figures circulated for subcutaneous use trace to community practice, not to any published study, and no human toxicology exists for the copper load a systemic dose would deliver. The Pickart literature most often cited for GHK-Cu is mechanistic and wound-repair work, not injectable dosing [1][2][3].
Leuphasyl
Topical
2% Leuphasyl in formulation
Once or twice daily · 4-8 weeks
Lowest concentration shown to give significant wrinkle reduction in cosmetic testing; 2% was the threshold at which measurable improvement appeared over ~2 months of daily use [6].
5% Leuphasyl in formulation
Once or twice daily · At least 4 weeks
Manufacturer in-vivo concentration; 5% Leuphasyl reduced wrinkles ~11% after 28 days, and ~25% (up to 47%) when paired with 5% Argireline [6].
Best suited for
GHK-Cu (Copper Peptide)
Anti-Aging Warriors
If fine lines, sagging skin, and lost elasticity are your enemies, GHK-Cu is your secret weapon. It ramps up collagen and elastin production—the two proteins responsible for keeping your skin firm and youthful [1][2]. Studies show it can tighten loose skin and improve elasticity better than many popular skincare ingredients [1][2].
Wound Healing Champions
Whether you're recovering from surgery, dealing with stubborn wounds, or healing from a cosmetic procedure, GHK-Cu accelerates the entire repair process [4]. It attracts immune cells, builds new blood vessels, and stimulates the growth factors your body needs to rebuild tissue faster and better [1].
Scar Reducers
GHK-Cu doesn't just heal wounds—it helps remodel scar tissue. By regulating how your body lays down collagen during healing, it can help scars become flatter, softer, and more like surrounding normal skin [6]. It even reduces the TGF-beta signals that lead to thick, raised scars [12].
Hair Growth Seekers
Research shows GHK-Cu can enlarge hair follicles and activate the Wnt/beta-catenin pathway—the signaling system that tells hair follicles to grow [1]. If you're noticing thinning hair or increased shedding, this peptide may help stimulate thicker, healthier growth over time.
Leuphasyl
Expression line reduction
Leuphasyl is particularly well-suited for individuals focused on expression line reduction. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Fine line prevention
Leuphasyl is particularly well-suited for individuals focused on fine line prevention. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Age management
Leuphasyl is particularly well-suited for individuals focused on age management. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Non-invasive wrinkle reduction
Leuphasyl is particularly well-suited for individuals focused on non-invasive wrinkle reduction. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Side effects
GHK-Cu (Copper Peptide)
Common
- Injection site redness
- Skin tingling (topical use)
- Minor bruising
- Mild swelling at injection site
Uncommon
- Mild headache
- Temporary skin purging (topical)
Serious
- Allergic reaction
Leuphasyl
Common
- Mild discomfort at treatment site
- Mild skin tingling
- Mild redness at application site
Uncommon
- Temporary skin dryness
Serious
- Severe allergic reaction
Safety & evidence
GHK-Cu (Copper Peptide)
Evidence level
Strong preclinical (extensive animal studies)
FDA status
Research compound
Safety overview
GHK is a peptide the body makes on its own — it turns up in human blood serum and cerebrospinal fluid, where it binds copper [5]. The peptide's original describer reports that the amount circulating falls with age, from roughly 200 ng/mL around age 20 to about 80 ng/mL by age 60 [2]. That is a description of what declines, not evidence that replacing it does anything. Almost all of the safety evidence is topical or laboratory work. The one randomized human trial of topical GHK-Cu — 13 patients using it after CO2 laser resurfacing — reported no safety problems, but also found no objective benefit over the control regimen [7]. There is no human safety data for injected GHK-Cu by any route [13]. That matters more than usual here, because the molecule carries copper: a systemic dose delivers a copper load, and no human toxicology study has measured what that load does.
Contraindications
- Wilson's disease or copper metabolism disorders
- Known allergy to copper or peptide components
- Active cancer or history of cancer
- Pregnancy or breastfeeding
- Children and adolescents
Leuphasyl
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Leuphasyl (Pentapeptide-18) has been studied in cosmetic research for over 15 years. This topical enkephalin-mimetic peptide demonstrates an excellent safety profile in cosmetic formulations, with no reported serious adverse effects in clinical applications. As a topical cosmetic ingredient, it avoids systemic absorption concerns associated with injectable treatments. The peptide is well-tolerated across all skin types including sensitive skin. Individual responses can vary with formulation and concentration, but most effects are manageable with standard cosmetic application protocols.
Contraindications
- Known hypersensitivity to peptides
- Open wounds or broken skin at application site
- Active dermatological infections at application site
Which is right for you?
Choose GHK-Cu (Copper Peptide) if...
- Skin rejuvenation and anti-aging
- Wound and injury recovery
- Scar reduction
- Hair growth support
Choose Leuphasyl if...
- Expression line reduction
- Fine line prevention
- Age management
- Non-invasive wrinkle reduction