Is collagen worth taking? What studies say about its effects and what they don’t

Short answer: it depends on what you expect from collagen. Most of the research is on skin: a meta-analysis of 26 randomised studies with 1,721 participants found better skin hydration and elasticity compared with placebo (Pu et al., 2023). Another meta-analysis, however, showed that the improvement appears only in company-funded studies, and independent studies did not measure it (Myung and Park, 2025). For hair, nails and joints there are first promising studies, but no certainty. So collagen makes sense to try for at least 3 months with realistic expectations, not as a guaranteed solution.

Of all the areas, skin is the best researched. The meta-analysis by Pu et al. (2023) combined 26 randomised studies with 1,721 participants and found better skin hydration and elasticity compared with placebo. The authors, however, described a number of biases in the included studies and call for larger studies. What exactly the studies measured, and with which collagen, we go through in our article Marine collagen and skin: what science really says.

The meta-analysis by Myung and Park (2025) went through 23 randomised studies with 1,474 participants. Taken together, hydration, elasticity and wrinkles improved, but once the studies were split by funding, the effect appeared only in company-funded studies. Neither independent studies nor high-quality studies measured an improvement, and the authors conclude that clinical evidence for collagen against skin ageing is still lacking. We sell collagen, and that is exactly why we write this openly.

In a study of 114 women, hair diameter after 24 weeks on 1,000 mg of fish collagen peptides a day was larger than with placebo (Hwang et al., 2026). Two of the five authors work in product development at a food supplement company, and the result applies to one specific raw material. For nails, 25 people with brittle nails took 2.5 g of collagen peptides a day for 24 weeks: their nails grew 12% faster and broke 42% less often, but the study had no placebo group (Hexsel et al., 2017). More detail in our article Collagen for hair: what studies say and on the Collagen for nails page.

In a study of 147 athletes without joint disease, joint pain when walking decreased more than with placebo after 24 weeks on 10 g of collagen hydrolysate a day, but data could be evaluated for only 97 of them (Clark et al., 2008). In 139 athletes with knee pain, pain during sport decreased more than with placebo after 12 weeks on 5 g of collagen peptides a day, while pain at rest did not differ significantly from placebo (Zdzieblik et al., 2017). Collagen does not treat osteoarthritis or any other joint disease, and long-term pain is a matter for a doctor. More in our article Collagen and joints: an honest review of the evidence.

A common objection is that collagen is broken down in the stomach like any other protein. Iwai et al. (2005), however, measured collagen peptides in the blood of volunteers after they drank pork and chicken collagen hydrolysate, mainly prolyl-hydroxyproline (Pro-Hyp), peaking after 1 to 2 hours and falling to half after 4 hours. Absorption into the blood does not by itself mean an effect on the skin, but it is the first step. In detail in our article Is the collagen I drink absorbed?

If you are allergic to fish, do not take marine collagen: fish collagen is a proven allergen, and antibodies reacted to it in five out of eight patients with fish allergy (Hamada et al., 2001). It makes no sense as a substitute for treatment, for example for osteoarthritis or hair loss caused by iron deficiency, or as a substitute for protein from food, because it does not contain all the essential amino acids. If you expect a change within a week, you will be disappointed: studies assessed the results after 12 to 24 weeks (Zdzieblik et al., 2017; Hwang et al., 2026). If you tend to get kidney stones, are pregnant, breastfeeding or taking medication, talk to your doctor first, and find out more in our article Side effects of collagen: what you should know.

1. Every day. The studies in this article used 1 to 10 g a day (Hwang et al., 2026; Clark et al., 2008), and one collalloc sachet contains 3.3 g.
2. In a cold or lukewarm drink, no hotter than 60 °C. In water, juice, milk or a smoothie, not in hot coffee or tea.
3. For at least 12 weeks. Only then does it make sense to assess the result, ideally using photos taken in the same light.
4. Together with a varied diet. Collagen does not replace protein or micronutrients from food.

The studies did not prescribe any particular time of day, and what matters is regularity. More in our article How to take collagen correctly.

collalloc kolagen is hydrolysed marine collagen with a molecular weight of around 500 Da, with no sweeteners, colourings or flavourings. If you do not want to mix anything, you can reach for the liquid NANO 2.0 with vitamin C, which contributes to normal collagen formation for the normal function of skin. Collagen itself has no approved health claim in the EU (Regulation 432/2012), which is why we talk about research rather than promises. We test microbiology for every production batch and heavy metals every month in an external laboratory, and you will find the results on the product page and on the Laboratory page.