Collagen Peptides for Skin Aging
Oral collagen peptides show preliminary evidence for modestly improving skin elasticity, hydration, and wrinkles, but the supporting trials are largely industry-funded and major regulators have not endorsed the claims.
Why this grade7-layer evidence engine
Two meta-analyses point the same direction. Choi 2019 (PMID 30681787), pooling 11 RCTs (n=805), found significant gains in skin elasticity (SMD 0.72) and hydration (SMD 0.31) with modest wrinkle improvement versus placebo. Pu 2023 (PMID 37432180), covering 26 RCTs (n=1,721), confirmed the hydration and elasticity benefits, and the representative Verisol RCT (PMID 24401291, n=114) showed reduced eye-wrinkle volume after 8 weeks at 2.5 g/day. This consistent positive signal is what lifts the grade to preliminary evidence.
The grade stays at B rather than higher because the evidence base has serious limitations. Nearly all underlying trials were funded by collagen manufacturers (Gelita/Verisol, Rousselot), Pu 2023's funnel plot suggested publication bias inflating the pooled effect, and heterogeneity across sources, doses (2.5-10 g/day), and durations was moderate-to-high. Most participants were middle-aged women, limiting generalizability.
Regulators have not backed these claims. The EU EFSA concluded 'a cause and effect relationship has not been established between the consumption of collagen hydrolysate and maintenance of joints,' and separately rejected the Verisol skin-elasticity claim. The US FDA lists collagen only as a food ingredient (flavoring/flavor enhancer), not an efficacy endorsement, and the UK NHS offers no guidance and excludes it from its vitamins and minerals list. The mismatch between a large reported effect and cautious independent regulators is why this is graded as promising but unproven.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.625
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status