At first glance, the idea sounds persuasive. However, after ingestion, the body breaks down collagen, like any other protein, into amino acids and peptides. These compounds enter the bloodstream and support the body’s broader metabolic needs. This fact alone doesn't prove that collagen supplements are useless, but it does make the marketing's confidence seem suspiciously ahead of the evidence.
Yet outside of academia, that confidence is everywhere. When I worked as a nutritionist in a supplement store, I often explained that hydrolyzed collagen never seemed to offer anything distinctly impressive for skin health. The responses were predictable: “My friend takes it, and her skin looks great,” or “I saw doctors citing studies showing benefits.”
The economic logic behind this phenomenon is straightforward. Collagen supplements sit at the crossroads of preventive health, protein marketing, and the appealing idea of “beauty from within.” Suggestive packaging, vague claims about skin quality, strategic ingredient blends, and influencer endorsements often make weak assertions seem convincing.
Few products illustrate this dynamic better than Verisol [1], one of the most well-known patented collagens on the market. Its promoters present it not just as another protein, but as a technological ingredient supposedly stimulating fibroblasts and reducing wrinkles, enhancing elasticity, hair, and nails. However, when we examine the clinical evidence, the case appears much less impressive than the marketing suggests.
The Efficacy of Verisol
Verisol is a patented product from Gelita, a major player in the gelatin and collagen industry. The company responded to a rising demand for “beauty from within” products and promoted Verisol as uniquely stimulating fibroblasts—the cells responsible for producing collagen in the body—and boosting collagen production, something conventional collagen supplements supposedly couldn’t do.
Their promotional materials also reference several bibliographic citations to support this claim.
Beyond the Promotional literature
A 2014 study involved 108 women aged 45 to 65 in a randomized, double-blind, placebo-controlled trial. Researchers evaluated wrinkles and conducted skin biopsies at the start, during, and after the supplementation.
The intervention group reduced wrinkle volume by an average of 20.1 percent after eight weeks, with some participants experiencing reductions of up to 49.9 percent. Researchers also noted that proteins associated with body-generated collagen, such as elastin, increased by 18 percent in the intervention group.
Based on these findings, the authors concluded that oral collagen intake significantly reduces wrinkle volume, highlighting that the results are specific to Verisol’s formulation.
Despite the study design, the article lacks transparency, with unstated conflicts of interest, funding sources, or study limitations. [2] Additionally, several technical limitations decrease confidence in the conclusions:
- The final sample showed high variability within groups in wrinkle volume, indicating significant individual differences. Without subgroup analyses or stratification by baseline severity, it is unclear whether the effect was consistent across participants or influenced by specific subgroups.
- Dietary intake of collagen was not tracked, and compliance with behavioral restrictions was primarily assessed via self-report.
- Although the study is described as randomized and double-blind, the authors do not explain how the random sequence was generated or how “blinding” was implemented for participants, investigators, and evaluators. This lack of detail raises concerns about potential selection bias and measurement bias.
Similar limitations are seen in another study focused on nail health. In this study, researchers assessed whether a 6-month daily intake of Verisol could improve brittle nail symptoms and promote nail growth and strength. By the end of the study, and during the four weeks afterward, the intervention group reported positive effects.
The authors briefly discussed limitations, noting that the open-label, uncontrolled design poses risks of methodological bias and that behavioral changes could have affected the results. Once again, the paper does not disclose conflicts of interest.
However, the authors did not explain how they measured participant adherence, making it difficult to determine whether consistent supplement intake or confounding factors influenced the reported results. They also relied on subjective assessments for key outcomes, such as perceived nail growth.
Systematic Reviews
No systematic review has yet included studies that focus solely on Verisol collagen. The most similar examples analyze different protocols and types of hydrolyzed collagen, such as an article published in 2021 in the International Journal of Dermatology.
This review analyzed 19 studies involving 1,125 participants, with an average age of around 50 years; women made up 95% of the sample. Study durations ranged from 4 to 16 weeks, and researchers used various formulations and assessment methods. The meta-analysis showed significant improvements in skin hydration, elasticity, density, and wrinkle reduction in the supplemented groups.
The authors concluded that, despite the variability, collagen peptides may help improve signs of skin aging, with effects observable after about 90 days and lasting up to four weeks after stopping supplementation. The supplementation was safe and associated with no significant adverse events. However, subgroup analyses revealed important nuances in measurement:
- For hydration, only the studies that reported outcomes in micrometers showed a significant difference.
- For elasticity, only studies that measured the outcome in megapascals, a unit used to express pressure and mechanical resistance, showed a positive effect. Studies that used other units or evaluation methods did not show a benefit.
Among the study’s limitations, methodological variability stands out, especially in the formulations and assessment methods. The studies also lack consistent details about participants’ lifestyles, which could significantly affect skin health.However, for me, the main limitation is the absence of a systematic review of funding sources and conflicts of interest. I examined the articles included in the review and found that two studies, classified as low risk by Czajka and Koizumi, received funding from collagen manufacturers and involved researchers employed by those companies. While this does not automatically invalidate the findings, it raises the possibility that the studies might overstate the effects and underscores the importance of cautious interpretation.
A systematic review published in The American Journal of Medicine last year addresses these limitations more directly. Unlike earlier analyses, they explicitly included funding sources and methodological quality as key parts of their interpretation.
The authors examined 23 randomized clinical trials involving 1,474 participants, with an average follow-up of 12 weeks. Of these trials, 13 were rated as good quality and 10 as having “some concerns.” Initial analysis showed significant improvements in hydration, elasticity, and wrinkle appearance with supplementation.
However, sensitivity analyses identified a key limitation. Excluding studies with extremely positive results, hydration and elasticity still remained statistically significant but with much smaller effect sizes. When the Koizumi study, cited earlier, was removed, the improvement in wrinkles was no longer statistically significant.
Subgroup meta-analyses indicated that:
- Trials without industry funding showed no effect of collagen supplementation on any outcome, while funded studies reported consistent improvements in hydration, elasticity, and wrinkles.
- High-quality studies found no significant effects, while lower-quality studies showed a significant improvement only for elasticity.
The authors concluded that although previous clinical trials and meta-analyses have reported benefits of collagen supplementation for skin properties, these effects were not confirmed when analyses were restricted to studies without industry funding or those with higher methodological quality. Additionally, no clear physiological explanation currently exists for how amino acids and peptides derived from ingested hydrolyzed collagen could be selectively delivered to the skin to boost dermal collagen levels.
In my view, a simple explanation can clarify why collagen often only appears to “work" in funded or weaker studies. More rigorous trials better control confounding variables, such as lifestyle, sun exposure, and diet. They also follow stricter procedures for randomization, measuring outcomes, and ensuring transparency in analysis. When researchers lack industrial funding or ties to manufacturers, they are less likely to report inflated effects or overly positive interpretations.
When it comes to collagen supplementation, reported benefits generally appear mainly in small, weakly designed, or stakeholder-funded studies. As methodological rigor improves and conflicts of interest lessen, the observed effects tend to decrease and often vanish.
[1] A specific composition of bioactive collagen peptides derived from the enzymatic breakdown of type I bovine (cow) collagen.
[2] The published paper omits that one author had ties to Gelita, and another co-invented Verisol.
Sources: Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis. Skin Pharmacol Physiol. DOI: 10.1159/000355523.
Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails. J Cosmet Dermatol. DOI: 10.1111/jocd.12393.
Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis. Int J Dermatol. DOI: 10.1111/ijd.15518.
Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Med. DOI: 10.1016/j.amjmed.2025.04.034.
