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Collagen Peptides for Hair Loss

Verdict: Insufficient Evidence

Across 3 PubMed studies, the evidence for Collagen Peptides in Hair Loss grades Tier U — unverified / insufficient. Research is still too limited to draw a firm conclusion.

U ⚫ U Unverified Insufficient Evidence

🔬Why this grade7-layer evidence engine

⚖️

Scoring transparency

All scores computed by a 7-layer evidence engine — fully auditable
Raw score 0.43
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
U · Insufficient Evidence
Confidence
65%
Broadly consistent
Evidence level
E6
Multiple smaller RCTs (n<500)

How strongly each layer supports this effect

lower = less supportive
L11 AI re-checkIndependent read
0.20
L2 PubMedPrimary literature
0.40
L1 ExamineGlobal benchmark
0.50
L3 MechanismPlausibility
0.50
L5 Clinical bodiesAuthoritative stance
0.55
Against Mixed Supports
▸View the full decision path (audit trail)
  1. compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.43
  2. tier_from_score — 依分數區間映射至 tier letter
  3. apply_hec_rules — 無高階證據可裁決
  4. tier_strict_requirement_check — Tier 條件達標，未降階
  5. detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
  6. decide_status — 依 tier + dispute 結果決定 status

📄PubMed studies (3)L2 · primary research & systematic reviews

Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss
PMID: 37357646 2023 隨機對照試驗 n = 83
Finding: Group A (supplement + standard) showed significantly higher GAS than Group B (standard alone) at week 12: 1.67 ± 0.16 vs 0.66 ± 0.20, p<0.001. Responders (GAS ≥2): 50% Group A vs 23% Group B. Well tolerated.
🟠 Limited quality ⚠️ Industry-funded Effect size: Mean GAS difference ~1.0 (p<0.001); responder rate 50% vs 23%
View on PubMed
Effect of a Hydrolyzed Collagen, Vitamin, and Zinc Containing Nutritional Supplement on Telogen Effluvium
PMID: 41346549 2025 Other n = 343
Finding: Significant improvements in all hair parameters at T1 and T2 (p<0.001). Pull test showed reduced shedding sustained during washout. Mild side effects in 10 patients.
🟠 Limited quality ⚠️ Industry-funded Effect size: Not pooled; all parameters p<0.001 vs baseline
View on PubMed
Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails (Hexsel et al.)
PMID: 28786550 2017 RCT (open-label) n = 25
Finding: 12% increase in nail growth rate; 42% decrease in broken-nail frequency; 64% global improvement during treatment, 88% at 4 weeks post-treatment.
🟠 Limited quality ⚠️ Industry-funded Effect size: Nail growth +12%; broken nails -42%
View on PubMed

🏛️Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …

L4a US FDA
Supportive
COLLAGEN — CAS Reg. No. 9007-34-5; Other Names: COLLAGENS, ATELOCOLLAGEN; Permitted Technical Effects: FLAVOR ENHANCER, FLAVORING AGENT OR ADJUVANT, SOLVENT OR VEHICLE. source↗
L4b EU EFSA
Against
a cause and effect relationship has not been established between the consumption of collagen hydrolysate and maintenance of joints source↗
L4d TW TFDA / 衛福部
Cautious
膠原蛋白為人體本身就可自行合成之物質……（口服）經過消化作用，變成小分子的胺基酸，未必能在體內重新合成膠原蛋白；（塗抹式）僅可能達到表面保濕、潤澤肌膚的效果，無法吸收再利用。 source↗
✓PMID 100% verifiedevery citation checked via NCBI Entrez
🔬3 PubMed studiesindependently re-checked by multiple sub-agents
engine_version: v1.0 claim_id: CLM-COND-hair-loss-INT-collagen-peptides-001 繁體中文版 →