Does collagen reduce skin aging?
Short answer
Unclear; higher-quality trials found no effect.
Reviews pooling many trials found better skin hydration and elasticity. But a 2025 review found the benefit only in trials funded by drug companies; trials without that funding, and high-quality trials, showed none.
This page says what the research shows. It does not say whether you should take collagen.
Where the evidence stands
Each dot is one on-topic paper. Steps near the top answer the question more directly. Select a dot to see the study.
↑ Stronger evidence
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Trials in people: wrinkles, skin elasticity and moisture
Trials that measured skin wrinkles, elasticity and hydration directly.
15 -
Trials in people: other measures
Trials that measured other health or performance measures.
1 -
Trials in people: lab tests or safety
Trials that measured lab tests, side effects or safety.
0None among the papers we read.
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Population studies
Studies that followed or surveyed groups of people. They show links, not causes.
0None among the papers we read.
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Blood levels and genes
Studies that link blood levels or genes to health.
0None among the papers we read.
↓ Weaker evidence
- Points to benefit
- Mixed
- No difference
- No direction
- Points to harm
Not on the ladder: 6 reviews of many studies (shown below). Counts are papers, not people. Some studies appear in more than one paper.
See every studyWhat we found
- The largest review here pooled 26 trials with 1721 people. Collagen gave better skin hydration and elasticity than placebo, but the authors found several biases in the trials. Pu 2023
- A 2025 review of 23 trials with 1474 people found benefits overall, but none in trials without drug-company funding or in high-quality trials. Myung 2025
- Not every trial agreed. In 99 women, collagen raised skin water content but not elasticity. A trial lasting 16 weeks saw no change in elasticity or hydration. Miyanaga 2021, Žmitek 2024
- Several tested drinks mixed collagen with vitamin C, zinc, biotin or joint compounds, so the effect of collagen alone cannot be separated. Bolke 2019, Czajka 2018, Žmitek 2024
What the research says
Reviews find better hydration and elasticity
Four reviews of placebo trials found better skin hydration and elasticity with collagen. The largest pooled 26 trials and 1721 people. A 2021 review pooled 19 studies with 1,125 people and also found fewer wrinkles.
A review of 10 trials and 646 people gave sizes: SMD 1.25 for hydration and SMD 0.61 for elasticity. SMD is a standard measure of the gap between groups; both favor collagen. The authors said bias risk was generally unclear.
Studies: Pu 2023, de Miranda 2021, Choi 2019, Danessa 2025
Benefit missing in independent and high-quality trials
A 2025 review pooled 23 trials with 1474 people. All together, collagen improved hydration, elasticity and wrinkles. But trials without funding from drug companies showed no effect on any of the three, while funded trials did. High-quality trials also showed no effect; low-quality trials showed better elasticity.
Its authors concluded there is no clinical evidence to support collagen for preventing or treating skin aging. It is the only review here that split results by who paid for the trials.
Studies: Myung 2025
Most single trials report gains over placebo
In women aged 45-65, 2.5 g a day for 8 weeks cut eye wrinkle volume more than placebo. In 69 women aged 35-55, 2.5 g or 5.0 g a day raised skin elasticity, the main measure, more than placebo.
Trials of low-weight collagen peptides reported better wrinkles, elasticity and hydration than placebo. One gave 1000 mg a day to 64 people for 12 weeks. These trials were small, and their abstracts rarely give the size of the wrinkle effect.
Studies: Proksch 2014, Proksch 2014, Kim 2018, Kim 2022, Seong 2024, Lee 2023, Lee 2025
Some trials found no change in key measures
Results were not uniform. In 99 women, collagen raised skin water content but left elasticity and thickness unchanged. In 87 women over 16 weeks, collagen with vitamin C eased wrinkles and raised skin density but did not change elasticity or hydration.
In an East Asian trial, skin density and moisture beat placebo after 84 days. Elasticity and wrinkles improved in both groups, only sooner with collagen. In another trial, moisture changes were too small to rule out chance.
Studies: Miyanaga 2021, Žmitek 2024, Vleminckx 2024, Proksch 2014
Many products were blends or company-linked
Several drinks mixed collagen with vitamin C, zinc, biotin or joint compounds. A drink with 2.5 g collagen raised hydration and elasticity in 72 women. A blend raised elasticity +40% compared with placebo in 120 people, so collagen's own share is unknown.
Four trials name a company link: funding from Vinh Hoan and Tosla, an unnamed sponsor for QUIRIS Healthcare's drink, and Newtree in a conflict statement. Eleven trials give no disclosure in PubMed, so other ties cannot be ruled out.
Studies: Bolke 2019, Czajka 2018, Žmitek 2024, Evans 2021, Kim 2018
What reviews of many studies found
Reviews pool or sum up earlier studies. They are not on the ladder, because they repeat studies already counted there.
Pooled review (meta-analysis) · Pu 2023
Pooled 26 randomized trials with 1721 people. Hydrolyzed collagen improved skin hydration and elasticity compared with placebo. The authors found several biases in the trials and called for larger trials to confirm the findings.
Pooled review (meta-analysis) · Myung 2025
Pooled 23 randomized trials with 1474 people. Overall, collagen improved hydration, elasticity and wrinkles, but trials without drug-company funding and high-quality trials showed no effect. The authors found no clinical evidence to support collagen for skin aging.
Pooled review (meta-analysis) · de Miranda 2021
Pooled 19 trials with 1,125 people aged between 20 and 70, 95% women. Collagen beat placebo on hydration, elasticity and wrinkles. The authors concluded that 90 days of use reduces skin aging.
Pooled review (meta-analysis) · Danessa 2025
Pooled 10 randomized trials with 646 people; findings apply mostly to women. Collagen at 1-10 g/day raised hydration (SMD 1.25) and elasticity (SMD 0.61). Bias risk was generally unclear, and results varied between trials.
How the research grew
The papers we read span 2014 to 2025. 6 of the 22 on-topic papers came out in 2024 to 2026. The earliest trial in people here is from 2014.
- 2014
- 2015
- 2016
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
Each dot is one on-topic paper, colored by what it found. Rings mark key papers:
- 2014. Early placebo trial found better skin elasticity. Proksch 2014
- 2014. Early trial: eye wrinkle volume fell versus placebo. Proksch 2014
- 2018. Largest single trial here: 120 people, blended drink. Czajka 2018
- 2023. Biggest pooled review: 26 trials, 1721 people. Pu 2023
- 2025. Turning point: no benefit in independent, high-quality trials. Myung 2025
Doses tested
9 trial papers gave a set daily amount in g a day, from 1 to 5. Each dot shows the dose and what the trial found.
- g a day0123456
- Points to benefit
- Mixed
- No difference
- No direction
- Points to harm
One row per paper, so a trial reported in two papers appears twice.
Not shown: 7 trial papers with no single daily dose in the abstract, or a different unit.
Who funds this research
Of 16 trial papers, 4 name a company tie (QUIRIS Healthcare, Newtree, Tosla, Vinh Hoan), 1 declares none, and 11 give no disclosure. Confidence was not lowered for stake alone, but a 2025 review found benefit only in drug-company-funded trials.
- Company stake 4
- No disclosure in PubMed 11
- No stake declared 1
- Bolke 2019Company stake
- Kim 2018Company stake
- Žmitek 2024Company stake
- Evans 2021Company stake
- Asserin 2015No disclosure in PubMed
- Proksch 2014No disclosure in PubMed
- Proksch 2014No disclosure in PubMed
- Seong 2024No disclosure in PubMed
- Lee 2023No disclosure in PubMed
- Miyanaga 2021No disclosure in PubMed
- Czajka 2018No disclosure in PubMed
- Vleminckx 2024No disclosure in PubMed
- Kim 2022No disclosure in PubMed
- Inoue 2016No disclosure in PubMed
- Lee 2022No disclosure in PubMed
- Lee 2025No stake declared
Funding rule. A stake is always shown. Confidence is lowered only when every supporting study comes from a party with a stake. "No disclosure in PubMed" means the PubMed record has no conflict-of-interest statement. It does not mean there is no conflict.
All 22 on-topic papers
Each paper shows what it tested, what it found, and who has a stake. Every paper also has its own page that explains how much it counts and how it fits. See every study as a list.
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Randomized trial · measured the question itselfLee et al., 2025Journal of microbiology and biotechnology · PubMed
Skin Anti-Aging and Moisturizing Effects of Low-Molecular-Weight Collagen Peptide Supplementation in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.
70 people · 70 healthy adults
Tested1,650 mg a day of a collagen peptide product for 8 weeks, then 2 weeks off, vs placebo
The collagen group had better wrinkle depth, height and visual scores than placebo. Elasticity, hydration and skin density also improved. No adverse events were reported.
Points to benefitNo stake declaredAbstract onlyAuthors declare no financial conflicts of interest.
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The Effects of Dietary Supplementation with Collagen and Vitamin C and Their Combination with Hyaluronic Acid on Skin Density, Texture and Other Parameters: A Randomised, Double-Blind, Placebo-Controlled Trial.
87 people · 87 women aged 40 to 65
Tested5 g hydrolysed collagen with 80 mg vitamin C, with or without 30 mg hyaluronic acid, for 16 weeks, vs placebo
Both products improved skin density, texture and wrinkle severity compared with placebo. Neither changed skin elasticity or hydration. Adding hyaluronic acid gave no extra benefit.
MixedCompany stakeAbstract onlyFunded in part by Tosla d.o.o., which made the study products.
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Randomized trial · measured the question itselfSeong et al., 2024Journal of cosmetic dermatology · PubMed
Low-molecular-weight collagen peptides supplement promotes a healthy skin: A randomized, double-blinded, placebo-controlled study.
100 people · 100 healthy adults
TestedA low-weight collagen peptide product vs placebo, measured at 4, 8 and 12 weeks
Compared with placebo, the collagen group had better skin roughness and wrinkle height measures and better elasticity at Week 12. Hydration also changed more. No related adverse events.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfVleminckx et al., 2024Journal of cosmetic dermatology · PubMed
Influence of collagen peptide supplementation on visible signs of skin and nail health and -aging in an East Asian population: A double blind, randomized, placebo-controlled trial.
85 people · 85 healthy women aged 43 to 65 in East Asia
Tested5 g a day of collagen peptides for 84 days, vs 5 g maltodextrin placebo, with the same face cream for all
After 84 days, skin density and moisture were better than placebo. Elasticity and wrinkle visibility improved in the collagen group within 28 days; placebo group showed the same only after 84 days.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Oral intake of collagen peptide NS improves hydration, elasticity, desquamation, and wrinkling in human skin: a randomized, double-blinded, placebo-controlled study.
100 people · 100 women aged 30 to 60
Tested1650 mg a day of collagen peptide NS for 12 weeks, vs placebo
Compared with placebo, skin flaking, hydration, wrinkling and elasticity improved after 4, 4, 12 and 12 weeks. No side effects were seen.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Oral Supplementation of Low-Molecular-Weight Collagen Peptides Reduces Skin Wrinkles and Improves Biophysical Properties of Skin: A Randomized, Double-Blinded, Placebo-Controlled Study.
84 people · 100 adults with sun-aged, dry facial skin; 84 were analyzed
TestedLow-weight collagen peptides vs placebo for 12 weeks
After 12 weeks, wrinkle scale score, eye wrinkle volume, roughness, elasticity (R2 and R7), skin hydration and water loss were better than placebo. No adverse events were linked to the product.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Trial, not randomized · measured the question itselfLee et al., 2022International journal of dermatology · PubMed
Anti-aging effect of an oral disintegrating collagen film: a prospective, single-arm study.
22 people · 22 women
TestedA collagen film that melts in the mouth, used daily for 12 weeks, with no placebo group
The collagen film reduced wrinkle depth and number and raised skin elasticity and density. There was no comparison group, so changes cannot be tied to collagen.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfMiyanaga et al., 2021Skin pharmacology and physiology · PubMed
Oral Supplementation of Collagen Peptides Improves Skin Hydration by Increasing the Natural Moisturizing Factor Content in the Stratum Corneum: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.
99 people · 99 healthy Japanese women aged 35 to 50
Tested1 g or 5 g of collagen peptides a day for 12 weeks, vs placebo
Collagen raised skin water content and cut water loss. Skin elasticity and skin thickness did not change.
MixedNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfEvans et al., 2021Journal of cosmetic dermatology · PubMed
A randomized, triple-blind, placebo-controlled, parallel study to evaluate the efficacy of a freshwater marine collagen on skin wrinkles and elasticity.
Women aged 45 to 60
TestedA hydrolyzed fish collagen (Vinh Wellness Collagen) vs placebo for 12 weeks
After 12 weeks, the collagen group had a 35% drop in wrinkle score from baseline (P = .035), and 24% greater wrinkle reduction on the right face than placebo. Cheek elasticity rose in women 45-54.
Points to benefitCompany stakeAbstract onlyFunded by Vinh Hoan Corporation, which makes the tested collagen.
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A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density: Results of a Randomized, Placebo-Controlled, Blind Study.
72 people · 72 healthy women aged 35 or older
TestedA drink with 2.5 g collagen peptides plus vitamin C, zinc, biotin and other ingredients, for 12 weeks, vs placebo
The drink group had better skin hydration, elasticity, roughness and density than placebo after twelve weeks. The gains were largely kept four weeks after stopping.
Points to benefitCompany stakeAbstract onlyTests ELASTEN by QUIRIS Healthcare; COI mentions an unnamed sponsor. Authors declare no conflict.
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Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study.
64 people · 64 adults
Tested1000 mg of low-weight collagen peptide a day for 12 weeks, vs placebo
Skin hydration was higher than placebo at 6 and 12 weeks. At 12 weeks, wrinkle scores improved, and two of three elasticity measures were higher than placebo. No side effects were linked to the product.
Points to benefitCompany stakeAbstract onlyCompany Newtree Co., Ltd. is named as involved; authors and company declare no conflict.
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Daily oral supplementation with collagen peptides combined with vitamins and other bioactive compounds improves skin elasticity and has a beneficial effect on joint and general wellbeing.
120 people · 120 adults
TestedA daily drink with fish collagen, vitamins, joint compounds and other ingredients for 90 days, vs placebo
Skin elasticity rose +40% (P < .0001) compared with placebo. Skin samples showed better fiber layout. Joint pain fell by -43%.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfInoue et al., 2016Journal of the science of food and agriculture · PubMed
Ingestion of bioactive collagen hydrolysates enhance facial skin moisture and elasticity and reduce facial ageing signs in a randomised double-blind placebo-controlled clinical study.
Adults tested for facial skin condition
TestedTwo collagen hydrolysates, one with more of two small collagen pieces, vs placebo, measured at 4 and 8 weeks
The collagen with more small pieces improved facial moisture, elasticity (R2), wrinkles and roughness more than placebo and more than the other collagen. No adverse events.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfProksch et al., 2014Skin pharmacology and physiology · PubMed
Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis.
114 people · 114 women aged 45 to 65
Tested2.5 g a day of a branded collagen peptide (VERISOL) for 8 weeks, vs placebo
Eye wrinkle volume fell in the collagen group compared with placebo after 4 and 8 weeks (p < 0.05, 20%). Skin samples showed more procollagen type I (65%) and elastin (18%).
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · measured the question itselfProksch et al., 2014Skin pharmacology and physiology · PubMed
Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study.
69 people · 69 women aged 35 to 55
Tested2.5 g or 5.0 g of collagen hydrolysate a day for 8 weeks, vs placebo
Skin elasticity, the main measure, was higher than placebo in both dose groups at 8 weeks. Moisture and water loss changes did not reach significance. No side effects were noted.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Randomized trial · other health measuresAsserin et al., 2015Journal of cosmetic dermatology · PubMed
The effect of oral collagen peptide supplementation on skin moisture and the dermal collagen network: evidence from an ex vivo model and randomized, placebo-controlled clinical trials.
Adults in two placebo-controlled trials, plus lab tests on skin samples
TestedDaily collagen peptides by mouth vs placebo, up to 12 weeks
Skin hydration rose after 8 weeks of collagen peptides. Collagen density in the deep skin layer rose and collagen breakup fell after 4 weeks. Effects lasted to 12 weeks.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
23 studies, 1,474 people · Participants in 23 trials of collagen supplements for skin
TestedCollagen supplements compared with placebo, split by who paid for the study and by study quality
All 23 trials together showed better hydration, elasticity and wrinkles. Studies not paid for by drug companies and high-quality studies showed no effect. The authors found no clinical evidence to support use.
MixedNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Pooled review (meta-analysis)Danessa et al., 2025Indian journal of dermatology, venereology and leprology · PubMed
Effects of collagen-based supplements on skin's hydration and elasticity: A systematic review and meta-analysis.
10 studies, 646 people · 646 people in 10 randomized trials, mostly women
TestedCollagen supplements at 1-10 g/day, compared with control; median 3.5 g/day
Collagen raised skin hydration (SMD 1.25 (CI: 0.77-1.74)) and elasticity (SMD 0.61 (CI: 0.21-1.02)). Risk of bias was generally unclear and results vary between studies.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis.
26 studies, 1,721 people · 1721 people in 26 randomized trials
TestedHydrolyzed collagen by mouth, compared with placebo
Pooled results from 26 trials showed better skin hydration (Z = 4.94, p < 0.00001) and elasticity (Z = 4.49, p < 0.00001) than placebo. The authors found several biases in the trials.
Points to benefitNo stake declaredAbstract onlyNo competing interests declared.
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Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis.
19 studies, 1,125 people · People aged 20 to 70 (95% women) in 19 trials
TestedCollagen taken by mouth, compared with placebo; the abstract says benefits were seen with 90 days of use
Pooled results from 19 studies and 1,125 people favored collagen over placebo for skin hydration, elasticity and wrinkles. The authors say 90 days of use reduced wrinkles.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Collagen supplementation for skin health: A mechanistic systematic review.
10 studies · Healthy people and patients in 10 publications
TestedCollagen by mouth, whole or broken down, and how it might work in the body
Ten publications were included. Almost all reported benefits of collagen on skin, with no inconsistencies. The review also describes three ways collagen might work.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
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Oral Collagen Supplementation: A Systematic Review of Dermatological Applications.
11 studies, 805 people · 805 people in 11 placebo-controlled trials, covering skin aging, dry skin, pressure sores and cellulite
TestedCollagen by mouth, 2.5g/d to 10g/d for 8 to 24 weeks, compared with placebo
Eleven studies with 805 patients were reviewed. Collagen was linked to higher skin elasticity, hydration and dermal collagen density. No side effects were reported.
Points to benefitNo disclosure in PubMedAbstract onlyNo disclosure in PubMed.
19 papers we read and set aside as off topic
- Langer et al., 2024. Nutritional interventions for preventing and treating pressure ulcers. (pooled review (meta-analysis))
- Stanescu et al., 2025. Skin Aging and Carotenoids: A Systematic Review of Their Multifaceted Protective Mechanisms. (systematic review)
- Albuquerque et al., 2019. Interventions for morphea. (systematic review)
- Nukaly et al., 2026. Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials. (pooled review (meta-analysis))
- Milani et al., 2023. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study. (randomized trial)
- Schmidt et al., 1996. Treatment of skin aging with topical estrogens. (trial, not randomized)
- Liu et al., 2022. The potential of Streptococcus thermophiles (TCI633) in the anti-aging. (randomized trial)
- Baek et al., 2025. Hibiscus Collagen Alternative (VC-H1) as an Oral Skin Rejuvenating Agent: A 12-Week Pilot Study. (randomized trial)
- Dusabimana et al., 2024. Oyster hydrolysate ameliorates UVB-induced skin dehydration and barrier dysfunction. (animal study)
- Riml et al., 2011. Aesthetic improvements of skin grafts in nasal tip reconstruction. (other)
- Laimer et al., 2025. Efficacy and safety of rigosertib in patients with recessive dystrophic epidermolysis bullosa-associated advanced/metastatic cutaneous squamous cell carcinoma. (trial, not randomized)
- Schauer et al., 2022. Hemidesmosomal Reactivity and Treatment Recommendations in Immune Checkpoint Inhibitor-Induced Bullous Pemphigoid-A Retrospective, Monocentric Study. (population study: followed a group)
- Tukaj et al., 2018. Calcitriol Treatment Ameliorates Inflammation and Blistering in Mouse Models of Epidermolysis Bullosa Acquisita. (animal study)
- Cavallini et al., 2022. PN-HPT® (Polynucleotides Highly Purified Technology) in facial middle third rejuvenation. Exploring the potential. (population study: followed a group)
- Hashimoto et al., 2016. Clinical and immunological studies for 105 Japanese seropositive patients of epidermolysis bullosa acquisita examined at Kurume University. (population study: followed a group)
- Pujia et al., 2017. An update on the potential role of C-peptide in diabetes and osteoporosis. (opinion or narrative review)
- Birnbaum et al., 2015. A Review of Clinical Trials Conducted With Oral, Multicomponent Dietary Supplements for Improving Photoaged Skin. (systematic review)
- Rajakumar et al., 2008. Vitamin D status and response to Vitamin D(3) in obese vs. non-obese African American children. (trial, not randomized)
- Jeffrey et al., 2025. Rituximab for the Management of an Australian Cohort of Treatment Refractory Mucous Membrane Pemphigoid. (population study: one-time survey)
Words on this page
- SMD (standardized mean difference)
- A way to compare results measured on different scales. About 0.2 is a small effect, 0.5 medium, and 0.8 large.
- p-value (p =)
- How likely a result this large would be by chance if there were no real effect. Below 0.05 is usually called a clear result.
- Placebo
- A dummy pill or fake treatment, so people do not know which group they are in.
- Pooled review (meta-analysis)
- A study that combines the results of many earlier studies to get one overall answer.
How the short answer is set
Fixed rules turn the studies into the short answer, so the same studies always give the same answer. The rules start from GRADE, a standard system for rating evidence, in plain language.
| Confidence | What it means |
|---|---|
| High | We are confident the answer is right. |
| Moderate | The answer is probably right, but it could change. |
| Low (this page) | The answer may well change. |
| Very low | Any answer is very uncertain. |
| Not tested in people | Only cell or animal studies exist. |
Why low here
- Starts high: placebo trials measured wrinkles, elasticity and hydration directly.
- Lowered: trials were small, and reviews found biases or unclear bias risk.
- Lowered: results disagree; trials without drug-company funding, and high-quality trials, showed no effect.
- Not lowered for stake: one supporting trial declares no conflicts; most give no disclosure.
How this page was made
Label
- Search
- PubMed, Nov 14, 2026. Searches written by Claude Opus 5.5; papers ranked by PubMed
- First read of all 41 papers
- Claude Sonnet
- Independent second read
- Claude Haiku
- Disagreements settled by
- Claude Opus 5.5
- Page text written by
- Claude Opus 5.5
- Charts
- Drawn by code from the study records
- Source check by a person
- Not yet. Required before search engines may list this page.
- Expert review
- No
- Papers read in full
- 0 of 41; all from PubMed abstracts
- Method
- v0.2, created Nov 14, 2026
Search. We ran four PubMed searches for collagen supplements and skin wrinkles, elasticity and hydration: pooled and systematic reviews since 2012 (10 of 25), trials in people (22 of 134), population studies (10 of 43). The first number is how many papers we read; the second is how many PubMed found. We took the ones PubMed ranks as most relevant. See the full PubMed search. Of the 41 papers read, 22 were on topic.
Limits. Digestery reads at most about 60 papers per question, so large fields are sampled, not covered in full. Abstracts can leave out key details, such as side effects and funding.
Review queue
These items wait for a person. Search engines are asked not to list the page until the first one is done.
- OpenThe short answer is new. It waits for a source check by a person.
- OpenLee 2025 and Lee 2023 test the same product (collagen peptide NS); check for a shared sponsor and overlapping participants.
- OpenKim 2018: COI statement names Newtree Co., Ltd. alongside the authors; confirm whether Newtree made or funded the tested product.
- OpenBolke 2019: COI mentions an unnamed sponsor; confirm whether it is QUIRIS Healthcare, maker of the tested ELASTEN drink.
- OpenProksch 2014 tests branded VERISOL with no disclosure in PubMed; check full text for maker funding.
- OpenEleven of 16 trial papers have no COI statement in PubMed; full texts may show more company ties, which could lower confidence.
- OpenMiyanaga 2021 and Kim 2022 name trial registrations in the abstract that are missing from trialreg; Miyanaga 2021 was registered retrospectively.
- OpenNukaly 2026 (oral and topical peptides) judged off-topic because collagen is not named; its oral polypeptide subgroup may include collagen trials.
- OpenThe pooled reviews likely share many of the same trials, so they are not independent pieces of evidence.
- OpenAsserin 2015, Inoue 2016 and Evans 2021 give no participant count or dose in the abstract.
Page history
| Date | Change | Reason |
|---|---|---|
| Nov 14, 2026 | Page created from 41 papers. | First version of the page. |
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