What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
Collagen benefits: where the science stands
For skin, hair and nails: no.
Skin, hair and nails are what most people take collagen for, and the strongest evidence says it does not help: a combined review covering 23 trials found no real difference. As of August 2026, the verdicts on this page rest on evidence from 34 trials, drawn from the strongest research among the 3,417 papers on PubMed that mention collagen. Every claim is checked below.
3,417 papers on PubMed · evidence from 34 trials
Claim by claim
- Skin, hair and nailsWell studied, and it does not work. The biggest review covered 23 trials.
- JointsThe science is still forming. Results lean positive, but there is not much yet.
Pairs people ask about
The two sources we read
- 2025Meta-analysis · pools 23 trials, 1,474 people · no clear effect on skin, hair and nailssource
- 2025Meta-analysis · pools 11 trials, 870 people · moderate benefit for jointssource
Chosen as the strongest evidence out of 3,417 papers on PubMed. Every row links to its paper.
Fair questions
Does collagen work?+
For skin, hair and nails, the strongest evidence says no. The biggest review covered 23 trials.
Is collagen safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 2 sources, when PubMed lists 3,417?+
The 3,417 is every paper that mentions collagen in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 2 cover 34 trials between them, and every one is linked above. Both counts are measured, not estimated.