CWeak evidence, or evidence againstOther
The short answer
Small studies suggest possible skin and joint effects; the mechanism claimed on the packaging is not how digestion works. If you want the protein, whey or food is cheaper.
Who this is actually for
No group with a clear need. Collagen is digested into ordinary amino acids like any other protein.
What it is legally allowed to claim
Nothing. There is no authorised EU health claim for this substance, so any packet promising a specific benefit is making a claim it is not entitled to make. That is worth knowing before you judge the price.
How much is too much
No upper level.
Cautions and interactions
Generally well tolerated. Marine collagen is a fish allergen.
Ask a pharmacist before you start anything. Interactions with prescribed medicines are the most common way supplements cause harm, and they are easy to check. Bring the actual packet, or a photo of the ingredients panel, because doses and forms vary enormously between products. Nothing here is a substitute for advice about your own situation.