Both are cosmetic peptides applied to skin, working on completely different problems: SNAP-8 targets expression lines by damping muscle signaling, GHK-Cu targets collagen and wound healing.
Side by side
| SNAP-8 | GHK-Cu | |
|---|---|---|
| Class | Cosmetic octapeptide | Copper tripeptide |
| Status | Cosmetic ingredient | Research compound (cosmetic use of topical forms) |
| Route | Topical, in cosmetic solutions (not injected) | Subcutaneous injection |
| Typical vials | 10 mg, 20 mg | 50 mg, 100 mg |
| Dose range | 0.5 mg to 2 mg | 1 mg to 3 mg |
| Frequency | Daily topical application | Daily |
| Half-life | No human data | No human data |
| Dosing unit | milligrams | milligrams |
Pharmacokinetics
No curves are shown, on purpose.
No published human pharmacokinetics for SNAP-8 or GHK-Cu. Drawing one curve against an absent one would imply a comparison that cannot be made.
What the evidence supports
These grade how well each outcome has been studied in humans, never how well either compound works. A strong grade can sit on a negative result.
The strongest evidence for any claimed outcome is Human RCT for GHK-Cu and Human, observational for SNAP-8. That gap is the most important line on this page.
SNAP-8
| Outcome | Evidence |
|---|---|
| Wrinkle appearance, topical | Human, observational |
| SNARE complex interference | Mechanistic only |
| Any outcome from injection | No data |
GHK-Cu
| Outcome | Evidence |
|---|---|
| Skin appearance, topical | Human RCT |
| Wound healing, topical | Human, observational |
| Gene expression changes | Mechanistic only |
| Any outcome from injection | No data |
How to choose
They address different things
Expression lines from muscle movement versus skin quality and collagen. Choosing between them is really choosing which problem you have.
GHK-Cu has the longer track record
A long-established cosmetic ingredient with human skin studies.
SNAP-8's open question is whether it penetrates at all
Its proposed mechanism requires reaching nerve terminals, and whether a peptide that size crosses intact skin is unsettled.
At the syringe
At the default setup on each compound's own page, a 10 mg vial in 2 mL puts 50 mcg on every insulin unit, while a 50 mg vial in 5 mL puts 100 mcg on every unit. That is the number that decides whether a dose lands on a readable mark, and it is set by how much water goes in, not by the compound.