Dietary collagen and health

What is collagen and why integrate it

The  collagen constitutes about 30% of the total proteins of the human body, playing a structural and functional role in the extracellular matrix of nearly all connective tissues. At least twenty-eight types are known, but the most clinically and nutritionally relevant are type I (skin, tendons, bones), type II (articular cartilage) and type III (blood vessels, skin). Starting from about twenty-five years of age, the synthesis of endogenous collagen decreases with age gradually but progressively: a process associated with reduced skin elasticity, deterioration of joint function, and increased vulnerability of tendons to overload injuries.

The  collagen supplements available on the market are mainly divided into two categories with distinct modes of action:

• the peptides of hydrolyzed collagen, obtained by enzymatic hydrolysis of the native protein, have a reduced molecular weight which facilitates intestinal absorption and systemic distribution as biochemical signals capable of stimulating endogenous collagen synthesis in fibroblasts and chondroblasts;

• The  native collagen undamaged type II instead retains its original three-dimensional structure and acts mainly through a mechanism of oral immune tolerance, modulating the inflammatory response at the joint level. The distinction between these forms is essential for correctly interpreting the results of individual studies (Ivaskiene et al., 2025).

Skin, tissue repair and horizons of translational research

The systematic review by Ivaskiene et al. (2025), published in  Frontiers in Nutrition and based on over sixty clinical studies updated to October 2025, documents the benefits of collagen supplementation on  skin, joints, and connective tissues. Available data indicate that hydrolyzed collagen peptides improveskin elasticity, support joint function and promote post-exercise recovery, particularly if co-administered with vitamin C, silica, or resveratrol, which enhance their biological effectiveness. Athletes and elderly show a stronger response compared to the general population, likely due to a baseline deficit in turnover and repair mechanisms of endogenous collagen.

At the level of translational research, the study introduces a frontier perspective: the convergence between nutritional supplementation,  advanced biosensors and smart materials. Electrochemical and optical platforms – including molecularly imprinted polymer (MIP)-based sensors, surface plasmon resonance (SPR) systems, and fluorescent assays with collagen-binding peptides – allow real-time monitoring of key biomarkers such as CTX-I, matrix metalloproteinases (MMP), and hydroxyproline. These tools open concrete scenarios towards precision medicine where the individual response to collagen supplementation can be monitored and modulated in a personalized way (Ivaskiene et al., 2025).

Healthier joints: the study on native type II collagen

One of the most relevant contributions of recent literature concerns the potential of collagen to prevent or slow joint decline before the onset of overt pathology. The study by Möller et al. (2026), randomized double-blind placebo-controlled, enrolled seventy-four healthy subjects who experienced  joint discomfort during physical activity – a condition considered an early sign of cartilage degeneration, prior to any diagnosis of osteoarthritis.

Participants were randomly assigned to treatment with undenatured native type II collagen (UC-II) at a dose of 40 mg/day or placebo for 180 days. Both groups showed improvements in joint function measured by the KOOS score at the end of the period, but the UC-II group achieved significant benefits earlier than placebo for the sub-scores pain, symptoms, and quality of life. In the subgroup with more marked baseline joint discomfort (VAS > 40 mm), collagen induced a significant reduction in CTX-II levels – a blood biomarker of cartilage degradation – while in the placebo group these levels increased: a finding suggesting a protective action on the tissue itself, not merely symptomatic. Recovery time after a standardized physical exercise test was also significantly shorter in the treated group (Möller et al., 2026).

Collagen and metabolic syndrome: a multilevel action on risk factors

The narrative review by Pueyo-Arias et al. (2025), published in  Nutrition Research Reviews from the University of Navarra, addresses a topic of great public health relevance: the role of collagen in relation to metabolic syndrome (MetS), the cluster of alterations – abdominal obesity, hyperglycemia, arterial hypertension, decreased HDL cholesterol, and hypertriglyceridemia – that significantly increases the risk of type 2 diabetes e cardiovascular diseases.

The emerging picture is one of a biologically plausible multi-level action:

• on the front of  body weight, collagen peptides would promote satiety, stimulate GLP-1 secretion, and fatty acid oxidation through activation of PPAR-α and the AMPK signaling pathway;

• on the front of  glycemia, collagen would improve insulin sensitivity, the expression of the GLUT-4 transporter, and inhibit the DPP-IV enzyme – the target of a well-established class of antidiabetic drugs – thus prolonging the activity of the incretin hormones GLP-1 and GIP and supporting pancreatic β-cell function;

• the effect on  blood pressure is primarily attributed to the inhibition of the ACE enzyme, with reduction of angiotensin II and promotion of vasodilation mediated by bradykinin and nitric oxide;

• on the profile of  blood lipids, collagen peptides show the ability to increase HDL cholesterol and reduce LDL and triglycerides through modulation of PPAR-γ and AMPK;

• finally, a role of collagen in supporting the composition of intestinal microbiota, with an increase in the production of short-chain fatty acids and reduction of pro-inflammatory and oxidative mechanisms (Pueyo-Arias et al., 2025).

The review however emphasizes the need for larger and longer clinical trials to define optimal dosages and long-term effects.

What to consider when choosing a collagen supplement

In light of the available evidence, some practical considerations may guide those evaluating collagen supplementation. The  source and form of the supplement are decisive:

• hydrolyzed collagen has broader applications on skin, tendons, and metabolism;

• native type II collagen is more specific for joint health.

Dosage affects the results: the study by Möller et al. (2026) achieved significant effects with 40 mg/day of CN2 in the joint context, while for metabolic benefits the literature generally uses doses of 10–15 g/day of hydrolyzed collagen.

The  duration of integration it is a factor often underestimated: most positive effects emerge in studies of at least three-six months, and intervention periods that are too short risk not detecting real benefits even in the presence of genuine biological action.

The co-administration with  vitamin C is recommended by multiple researchers, as this micronutrient is essential for the endogenous synthesis of collagen as a cofactor of prolyl- and lysyl-hydroxylase.

As with any dietary supplement, it is advisable to consult your doctor or nutritionist, considering the quality of the product, the traceability of the source, and your individual health conditions.

Collagen in the circular economy: valorization of co-products

An aspect of fundamental importance, consistent with the vision of GIFT for a sustainable food system, concerns the origin of the raw material. Collagen is not 'produced' ex novo, but extracted through processes of upcycling from co-products of the meat and fish industry (skins, bones, scales, cartilage).

This circular economy strategy allows to:

• reduce food waste, transforming protein fractions otherwise destined for disposal into high value-added ingredients for human health;

• improve sustainability: the use of advanced extraction technologies (enzymatic or with green solvents) minimizes the environmental impact compared to the production of other protein sources;

• ensure traceability: the safety and efficacy of dietary collagen strictly depend on the control of the livestock or fishery supply chain of origin.

Dietary supplementation thus becomes not only an act of self-care but a piece of a regenerative bioeconomy that optimizes existing natural resources.

Conclusions

The body of recent research provides a picture of dietary collagen as a nutritional tool with solid biological bases and a favorable safety profile. The study by Möller et al. (2026) documents that native type II collagen improves joint function and reduces markers of cartilage degradation in healthy subjects experiencing discomfort from physical activity. The review by Pueyo-Arias et al. (2025) outlines plausible biological mechanisms through which collagen can act on the components of the syndromemetabolic syndrome, from body weight to blood sugar, from blood pressure to blood lipids and the microbiota. Ivaskiene et al. (2025) finally envision a future where collagen supplementation is embedded within a framework of  precision regenerative health, combining nutrition, biosensing and personalized biological monitoring. Research continues and the scientific basis for a conscious use of dietary collagen is consolidating.

Dario Dongo

Bibliography

• Ivaskiene, T., Viskelis, J., Streimikyte, P., Savickaitė, M., Mobasheri, A., & Kaspute, G. (2025). Collagen supplementation and regenerative health: advances in biomarker detection and smart material integration.  Frontiers in Nutrition, 12, 1716166. https://doi.org/10.3389/fnut.2025.1716166

• Möller, I., Martínez, K., Terradillos-Guillén, A., Costa-Larrión, E., Martínez-Puig, D., & Velasco-Álvarez, J. (2026). Efficacy and tolerability of native (undenatured) type II collagen supplementation for joint health in healthy volunteers: a randomized double-blind placebo-controlled study.  Nutrition Journal. Advance online publication. https://doi.org/10.1186/s12937-026-01302-0

• Pueyo-Arias, M., López-Yoldi, M., Navas-Carretero, S., González-Navarro, C. J., Zulet, M. L. Á., & Milagro, F. I. (2025). Collagen supplementation in metabolic syndrome: a narrative review unraveling the biological mechanisms and effects.  Nutrition Research Reviews, 39, e10. https://doi.org/10.1017/S0954422425100309