Methodology

How we rank UK collagen brands

PeptideClear ranks UK-available collagen supplements across the four sub-categories: hydrolysed marine, hydrolysed bovine, undenatured Type II (UC-II), and vegan precursor blends. Different criteria apply within each sub-category because the products serve different goals at different dose units.

Inclusion criteria (mandatory floor)

· UK availability via at least one major UK retailer (Cult Beauty, LookFantastic, Boots, Holland and Barrett, Amazon UK, or direct UK shipping).
· FSA-compliant labelling (no medicinal claims).
· Declared dose per serving in grams (Type I) or milligrams (UC-II).
· Source declared (marine, bovine, porcine, vegan precursor).

Ranking criteria for Type I (hydrolysed)

Dose per serving (30%): 10g+ is the evidence-base target (Shaw 2017 used 15g).
kDa molecular weight (15%): lower kDa absorbs better; 2 to 3 kDa is the benchmark for marine.
Source transparency (15%): wild-caught North Atlantic or audit-chain grass-fed bovine score top.
Third-party testing (15%): publishing or making available heavy-metals and purity tests.
Price per effective gram (15%): normalised to a 10g/day comparable cost.
Format breadth (10%): powder available at minimum; capsules and RTD as supplementary.

Ranking criteria for UC-II (Type II)

· Standardised dose at 40 mg/day UC-II (not Type I dose units).
· Source from chicken sternum cartilage with manufacturer named.
· Single-ingredient products score higher than multi-ingredient joint blends where UC-II is one of several actives.

Ranking criteria for vegan precursor blends

· Honest framing: vegan products do not contain collagen, they contain precursors.
· Lysine + proline + glycine plus vitamin C is the evidence-aligned minimum.
· Brands marketing "vegan collagen" without that distinction are excluded.

What we explicitly do not measure

· Skincare results from individual users (industry-funded RCTs vs independent meta-analyses dominate the evidence base; rankings stay on inputs, not output claims).
· "Premium positioning" beyond what is documented in source and testing.
· Brand celebrity endorsements.

Refresh cadence

Annual refresh, with mid-year update for material product changes (dose change, source change, new format launches).