Peptide supplements and skincare
These are the peptides you can buy today, and the only ones on this site with a meaningful body of human evidence behind them. Two different purchases: collagen, a powder you swallow, and the skincare peptides, which you apply. They are studied differently and regulated differently, so they are listed separately here.
Collagen peptides
The most-studied supplement I cover: randomised trials for skin and joints, modest effect sizes, and a concentration of authorship worth knowing about.
US legal status - Dietary supplement
Regulated as a dietary supplement in the US. Supplements are not FDA-approved; manufacturers are responsible for their own safety and labelling, and the FDA acts only after a problem surfaces.
- best collagen supplement
Best Collagen Supplement: Collagen Peptides and Powders Compared
The best collagen supplements by studied dose and testing: three NSF-certified powders, a UC-II option and how pills compare, with prices as of 3 October 2026.
Read guide→ - collagen peptide benefits
Collagen Peptide Benefits: What Human Studies Support
Skin, joints, bone and nails: what collagen trials measured, how large the effects were, and which benefit claims run past the evidence.
Read guide→ - collagen peptides for hair
Collagen Peptides for Hair: What the Evidence Covers
Hair claims for collagen lean on skin and nail research. What has been measured directly, what has not, and how to read before-and-after marketing.
Read guide→ - collagen peptides for joints
Collagen Peptides for Joints: What the Trials Found
Joint comfort and function trials for hydrolyzed collagen and undenatured type II collagen, with the doses, the effect sizes, and who paid for the research.
Read guide→ - collagen peptides for skin
Collagen Peptides for Skin: The Trial Evidence
Oral collagen for wrinkles and skin aging: what the hydration and elasticity trials measured, how strong the designs are, and how topical collagen differs.
Read guide→ - collagen peptides
Collagen Peptides: What the Human Trials Found
Hydrolyzed collagen has real human trials behind it. The effect sizes for skin and joints, the doses used, who funded the studies, and what is still open.
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Skincare peptides
Copper peptides and the signal peptides used in serums. Sold as cosmetics, which sets a hard limit on what a product may legally claim - and a useful test for spotting the ones that overstep.
US legal status - Cosmetic
Regulated as a cosmetic in the US. Cosmetics are not FDA-approved before sale, and may only make appearance claims - a product claiming to change the structure or function of skin is making a drug claim.
- argireline
Argireline (Acetyl Hexapeptide-8): The Study Evidence
Argireline is sold as a topical Botox alternative. What the randomised cosmetic studies measured, how large the changes were, and where the comparison breaks down.
Read guide→ - best peptide serum
Best Peptide Serums and Copper Peptide Serums, Compared
The best peptide serums by human evidence: palmitoyl pentapeptide-4, Argireline and 1% copper peptide picks, with prices as of 3 October 2026.
Read guide→ - ghk peptide
GHK Peptide: GHK vs GHK-Cu Explained
The free tripeptide and the copper complex are sold under one name and studied differently. What separates them, and where the marketing overreaches.
Read guide→ - copper peptides
GHK-Cu (Copper Peptides): Benefits, Dosage, Side Effects
GHK-Cu (copper peptides): what the research shows, typical cosmetic concentrations, side effects users report, and how legal status works for a cosmetic ingredient.
Read guide→ - ghk cu dosage
GHK-Cu Dosage Chart and Calculator: Cosmetic and Study Doses
GHK-Cu dosage chart: units per dose by vial size, a calculator, the under-10-ppm cosmetic concentration, and what published topical studies used.
Read guide→ - ghk-cu vs matrixyl
GHK-Cu vs Matrixyl: Two Different Peptide Stories
Copper peptides and Matrixyl-class signal peptides share a shelf and little else. Chemistry, study designs and evidence compared without picking a fake winner.
Read guide→ - glutathione dosage
Glutathione Dosage: Oral, IV and Injectable Study Doses
Glutathione dosage by route: 250-1,000 mg/day oral in trials, a 2 g/m2 IV study dose, the 200-1,200 mg IM clinic protocol, and 600 mg and 1,500 mg vials.
Read guide→ - glutathione injection
Glutathione: Injection Cost, Dosage, Side Effects and Legality
Glutathione injection cost in October 2026 ($32 to $275 a shot, $250 to $300 a drip), whether tablets and pills work, FDA-documented risks and legal status.
Read guide→ - matrixyl
Matrixyl (Palmitoyl Pentapeptide): The Evidence
What the cosmetic clinical research on Matrixyl measured, how the trade-name family differs, and why the studies do not transfer to every cream that names it.
Read guide→ - peptides for skin
Peptides for Skin: The Evidence Behind the Big Names
The four classes of cosmetic peptide, GHK-Cu in depth, whether any of it gets through skin, and how peptides compare with vitamin C and retinoids.
Read guide→ - snap-8
SNAP-8 (Acetyl Octapeptide-3): Benefits, Dosage and Side Effects
SNAP-8 (acetyl octapeptide-3): the topical cosmetic peptide explained - mechanism, the manufacturer-testing evidence, formulation use and legal status.
Read guide→ - snap-8 dosage
SNAP-8 Dosage: Formulation Concentration, Sourced
SNAP-8 dosage means formulation concentration, not an administered dose - what two vendor guides say about usage rate, sourced and explained.
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The compound pages
The same monograph treatment the research compounds get: evidence strength, what it rests on, and the legal position.
- Collagen & skinCopper tripeptide (carrier peptide)
GHK-Cu
Topical cosmetic anti-aging - fine lines, skin density and firmness, elasticity, photodamage, hyperpigmentation - and wound healing. Also marketed in hair-loss cosmetics.
- Collagen & skinEndogenous tripeptide antioxidant (gamma-L-glutamyl-L-cysteinyl-glycine)
Glutathione
Naturally synthesized in nearly all human cells as the body's principal intracellular antioxidant. Sold as an oral dietary supplement, and marketed by IV/wellness clinics and online sellers as an injectable "glutathione push" or "skin whitening" infusion - a use with no FDA-approved product behind it.
- Collagen & skinSynthetic octapeptide (topical cosmetic ingredient, INCI name Acetyl Octapeptide-3)
SNAP-8
Topical cosmetic anti-wrinkle ingredient in serums, gels and emulsions, marketed as a longer version of the neurotransmitter-release-inhibiting peptide family that includes Argireline (acetyl hexapeptide-8).