Tier 2 — strong

Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study

Ehrhardt Proksch, Dorothee Segger, Jürgen Degwert, Michael Schunck, Vivian Zague, Steffen Oesser

Skin Pharmacology and Physiology 2014 27(1):47–55

Bibliography

DOI: 10.1159/000351376
PubMed: PMID 23949208
Funding: No external grant funding statement disclosed in the paper. Study product (Verisol®) supplied by Gelita AG (Eberbach, Germany).
Competing interests: No explicit competing interests statement disclosed in the paper. Test product Verisol® was supplied by Gelita AG, a commercial manufacturer of collagen peptide ingredients that markets Verisol® directly. Co-authors Michael Schunck and Steffen Oesser were affiliated with CRI Collagen Research Institute (Kiel, Germany), a research entity closely tied to Gelita AG. Co-authors Dorothee Segger and Jürgen Degwert were affiliated with Skin Investigation and Technology (Hamburg, Germany), a contract skin-testing organisation. Substantial commercial conflict of interest across product supply and authorship affiliations despite the absence of a formal declaration.

Study snapshot

Design	Monocentric, double-blind, randomised, placebo-controlled, three-arm supplementation trial
Model	Healthy women aged 35–55 years, Fitzpatrick phototype I–IV, self-reported dry forearm skin
Sample	69 randomised (n=23 per arm × 3 arms); 62 completed
Intervention	Randomised 1:1:1 to (a) 2.5 g/day Verisol® bioactive collagen peptides (Gelita AG, porcine type I, avg MW 2.0 kDa), (b) 5.0 g/day Verisol®, or (c) 2.5 g/day maltodextrin placebo — once daily oral, dissolved in cold liquid, for 8 weeks.
Duration	8-week supplementation period; skin elasticity also reassessed 4 weeks after last intake (12-week total observation, 4-week regression phase)
Endpoints	Skin elasticity R5 value (Ur/Ue) by cutometer MPA 580 on volar forearm — primary; Skin hydration by corneometer CM 825 — secondary; Transepidermal water loss by DermaLab — secondary; Skin roughness by PRIMOS Compact 3D imaging of silicone imprints — secondary

What the study showed, in plain terms

Skin loses elasticity with age. It also gets drier and thinner. Cosmetic manufacturers have long claimed that swallowing collagen — usually as a powder mixed into a drink — can slow or reverse some of that decline. Until 2014, most of the evidence for those claims came from laboratory experiments on cells or animals, or from small studies without proper placebo controls. Real controlled trials in humans were scarce.

This trial was one of the first well-designed tests. Sixty-nine women aged 35 to 55 were randomly assigned to take one of three things every day for eight weeks: 2.5 grams of a specific collagen peptide called Verisol®, 5 grams of the same collagen, or a matched placebo powder that looked and tasted identical. Neither the participants nor the researchers making the measurements knew who was getting what. Skin elasticity, moisture level, water loss and roughness were measured on the forearm at the start, halfway through, at the end, and four weeks after the trial finished.

By the end of the eight weeks, skin elasticity had improved by about seven percent in both collagen groups compared to placebo — a small but statistically real effect. The higher 5-gram dose did not do noticeably better than the lower 2.5-gram dose, meaning 2.5 grams is enough. In women over 50, the improvement was more pronounced and — importantly — was still measurable four weeks after stopping the supplement, suggesting the change was in the deeper skin layers rather than a temporary surface effect. Hydration and water loss trended in a favourable direction, particularly in the older women, but did not clearly beat placebo. Skin roughness did not change.

Key findings

Skin elasticity (R5) improved ~7% versus placebo in both the 2.5 g/day and 5.0 g/day Verisol® groups at both 4 and 8 weeks (p<0.05 for both time points, both doses).
No significant difference between the 2.5 g/day and 5.0 g/day doses — 2.5 g/day was sufficient for the elasticity endpoint.
In the subgroup of women aged over 50, skin elasticity improvement was more pronounced and reached statistical significance versus placebo (p<0.05), with the effect still present at the 4-week regression follow-up (approximately 98% of the peak effect retained).
Skin hydration showed a ~11–14% increase in the over-50 subgroup after 8 weeks in both collagen groups versus placebo — trend favourable but did not reach statistical significance overall.
Transepidermal water loss was reduced by ~6–7% in the over-50 subgroup at 4 and 8 weeks — trend favourable, not statistically significant.
Skin roughness showed no significant change at 4 or 8 weeks in either collagen group versus placebo.
No treatment-related adverse events or side effects reported in any of the 69 participants across the 8-week supplementation period plus 4-week follow-up.

What this study can and cannot tell us

Female-only sample aged 35–55. Findings do not generalise to men, to younger or older women, or to non-Caucasian populations (phototype I–IV only was included).
Modest per-arm sample size (n=23). Secondary endpoints of hydration and TEWL likely underpowered — the favourable trends in the over-50 subgroup may reflect a true effect that the trial was too small to prove.
Skin elasticity measured on the volar (inner) forearm, a sun-protected site. This is defensible methodologically but the endpoint is not the visible facial skin outcome most consumers seek.
Placebo (maltodextrin) is a carbohydrate and does not control for the amino acid load of a protein supplement. A whey protein or casein placebo would be a stronger comparator.
Substantial commercial conflict of interest — Verisol® supplied by Gelita AG (its manufacturer), and co-authors Schunck and Oesser are affiliated with a Gelita-linked research institute. No explicit competing interests statement.
No dermal biopsy or biomarker measurement — the study measures functional skin parameters but does not directly demonstrate that collagen or elastin synthesis has changed. (The companion trial published later that year in the same journal — Proksch 2014 wrinkles — addresses this gap.)
Findings apply specifically to the Verisol® peptide composition and cannot be assumed to transfer to other collagen hydrolysates with different molecular weight distributions or peptide profiles.
Single centre, single investigator team. Independent replication in a different laboratory setting has been slow to accumulate.

Tier 3

Oral ingestion of collagen hydrolysate leads to the transportation of highly concentrated Gly-Pro-Hyp and its hydrolyzed form of Pro-Hyp into the bloodstream and skin

Misato Yazaki et al. · Journal of Agricultural and Food Chemistry · 2017

Tier 3

Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources

Hiroki Ohara et al. · Journal of Agricultural and Food Chemistry · 2007

Tier 3

Identification of food-derived collagen peptides in human blood after oral ingestion of gelatin hydrolysates

Koji Iwai et al. · Journal of Agricultural and Food Chemistry · 2005

Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study

Bibliography

Study snapshot

What the study showed, in plain terms

Key findings

What this study can and cannot tell us

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