Methodology

How we rank UK cosmetic peptide products

PeptideClear ranks cosmetic peptide products (GHK-Cu serums, Matrixyl 3000 formulas, Argireline creams, multi-peptide blends). The headline INCI position is the strongest single signal; the supporting criteria differentiate within a tier.

Inclusion criteria (mandatory floor)

· UK-stocked (Cult Beauty, LookFantastic, Boots, Space NK, Beauty Pie, Amazon UK, or direct).
· INCI declaration includes a named peptide ingredient.
· Pump or airless packaging where the peptide oxidises in jars (GHK-Cu, retinaldehyde-paired peptides).
· Compatible base (no low-pH conflict with copper peptide in same step).

Ranking criteria (weighted)

INCI position of named peptide (35%): top 8 ingredients is meaningful concentration; bottom third is trace.
Declared concentration (20%): brands publishing a number score higher than brands using "contains" language.
Supporting actives (15%): formulations pairing peptides with established collagen-supportive actives (vitamin C, niacinamide, hyaluronic acid) score higher than pure peptide-only formulas.
Base compatibility (10%): no low-pH glycolic or salicylic in the same step as copper peptides.
Packaging (10%): airless pump > opaque dropper > glass jar.
UK availability and price per gram of declared peptide (10%): available across multiple UK retailers, transparent £/gram calculation possible.

What we explicitly do not measure

· Brand marketing claims about results within a specific timeframe (ASA enforced).
· Before-and-after imagery (ASA position on this is restrictive for cosmetic actives).
· Individual user reviews (subject to selection bias).

Refresh cadence

Rankings reviewed twice yearly. New product launches added between cycles when they materially change the competitive landscape (a new declared-concentration entrant from a major UK retailer, for example).

Conflict of interest

Affiliate revenue funds editorial. Inclusion in rankings is not contingent on affiliate availability. The Ordinary, Niod, Beauty Pie products appear across rankings whether or not the specific product line carries an active affiliate.