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Collagen supplementation for skin health: a mechanistic systematic review

Meisam Barati, Masoumeh Jabbari, Roya Navekar, Fariba Farahmand, Reihaneh Zeinalian, Ammar Salehi-Sahlabadi, Nasrin Abbaszadeh, Amin Mokari-Yamchi, Sayed Hossein Davoodi
Journal of Cosmetic Dermatology 2020 19(11):2820–2829

Bibliography

PubMed
PMID 32436266
Funding
Funding statement (verbatim): "Student Research Committee, Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran, Grant/Award Number: 1397/70756"
Competing interests
The authors declared no conflict of interest.

Study snapshot

DesignSystematic review of clinical trials assessing effects of collagen supplementation on skin health parameters, with mechanistic focus on biological explanations for observed effects
ModelLiterature review — assessed 9,057 initial items reduced through screening to 10 included publications
SampleNot applicable — review paper. Aggregate evidence across included clinical trials.
InterventionReview methodology — trials covered used oral hydrolysed or intact collagen at doses ranging 500 mg to 10 g/day, durations 4 weeks to 12 weeks, in healthy or patient populations
DurationDatabase searches through the review methodology date; included publications spanned recent decades
EndpointsSynthesis of skin health outcomes across included trials; Identification of mechanistic pathways (direct fibroblast effects, M2-like macrophage polarisation, oral tolerance mechanisms); Assessment of consistency of findings across included studies

What the study showed, in plain terms

This 2020 systematic review evaluated the literature on oral collagen and skin health, with particular emphasis on possible biological mechanisms.

The search identified 9,057 records initially; after duplicate removal and screening, 31 full texts were assessed and 10 publications were included. The review authors reported that almost all included studies described favorable skin outcomes.

The review proposed three broad mechanistic routes: direct effects of collagen-derived peptides on fibroblasts, M2-like macrophage polarization, and oral-tolerance-related immune mechanisms. Much of that mechanistic explanation comes from preclinical evidence rather than direct mechanistic measurements inside the human trials. Because the review did not perform a meta-analysis, it supports biological plausibility and qualitative consistency rather than providing a pooled clinical effect size.

Key findings

  • The systematic search identified 9,057 initial records and ultimately included 10 publications.
  • The review authors reported that almost all included studies found favorable effects of collagen supplementation on skin-health parameters.
  • Three proposed mechanisms were emphasized: direct collagen-peptide effects on fibroblasts, M2-like macrophage polarization, and oral-tolerance-related immune mechanisms.
  • The review included both intact and hydrolyzed collagen interventions and did not generate a pooled quantitative effect size.
  • The Student Research Committee at Shahid Beheshti University of Medical Sciences supported the work; the authors declared no conflict of interest.

What this study can and cannot tell us

  • Only 10 studies were included, so the evidence base was small for a systematic review.
  • The review combined intact and hydrolysed collagen studies, which can obscure differences between preparations.
  • Several proposed mechanisms rely on cell and animal evidence rather than direct demonstration in the included human trials.
  • All included studies reported favourable findings, which raises the possibility of publication or selection bias.
  • The review did not perform a quantitative meta-analysis, so it does not provide a pooled estimate of clinical effect size.
  • The authors declared no conflict of interest.

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