Compare marine collagen on the grams of collagen in each daily serving, the format (powder, capsules, sticks or liquid) and the cost per gram. Marine collagen comes from fish, so check the allergen information, and remember collagen has no authorised health claims.
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What is marine collagen?
Marine collagen is collagen taken from fish, usually the skin or scales, and sometimes from shellfish. Which? says marine collagen is rich in type I collagen, the most abundant type in the human body.
Most marine collagen supplements are hydrolysed, meaning the collagen has been broken down into short chains called peptides, so you'll see "marine collagen peptides" and "hydrolysed marine collagen" on labels. This collection includes powders, capsules, sachet sticks and liquid marine collagen.
What are the benefits of marine collagen?
There are no authorised health claims for collagen, from fish or any other source, so we don't list benefits. Which? says there is still no scientific consensus that collagen supplements improve skin, any changes are likely to be small, very few long-term studies exist, and many studies are part- or fully funded by companies.
"Where evidence is limited or inconclusive, we should say so openly," says Andy Arshad, who runs SupplementHQ.
Some marine collagen products add vitamin C. Where a product is at least a source of vitamin C, it can say that "vitamin C contributes to normal collagen formation for the normal function of skin". That claim belongs to the vitamin C, not the collagen.
Marine vs bovine collagen: which is better?
Neither is proven to be better. Which? says marine collagen is in theory more easily absorbed and bovine collagen is often suggested for joints, but not enough research has been done to confirm it.
| Marine collagen | Bovine collagen | |
|---|---|---|
| Source | Fish skin or scales; some from shellfish | Cattle |
| Main collagen types (Which?) | Type I | Types I and III |
| Allergen to check | Fish, and crustaceans or molluscs if shellfish-derived | None of the 14 allergens from the collagen itself |
| Diet | Pescatarian; not vegan | Not vegetarian or vegan; not automatically halal |
| Authorised health claims | None | None |
"Choosing between marine and bovine collagen isn't simply about which is better. It involves understanding the source, collagen peptide specifications, traceability, manufacturing standards, price and suitability for different consumers. Neither source is automatically superior for every intended benefit," says Andy. Compare bovine collagen.
Is marine collagen safe if you have a fish allergy?
Check carefully, and speak to your GP if you're unsure. Fish, crustaceans and molluscs are among the 14 allergens that must be emphasised within the ingredients list of prepacked food, for example in bold.
Which? notes that some marine collagen supplements are sourced from shellfish, so the label may name a fish species, a shellfish or both. If you have any fish or shellfish allergy, bovine collagen avoids that source, though you should still read the full ingredients list.
How much marine collagen should you take a day?
There's no official recommended amount. Versus Arthritis says studies have used daily doses of between 1 and 10g of collagen hydrolysate, and that the best dose isn't yet known, so follow the label and don't exceed the stated daily serving.
"Some powders provide 10g of collagen per serving, while gummies and capsules often provide considerably less," says Andy. Check the grams of collagen per full daily serving, not per capsule or stick.
Marine collagen powder, tablets or liquid?
Choose the format you'll actually use, then compare the grams of collagen per day and the cost per gram. Powders usually give the most collagen for the money; capsules, sticks and liquids cost more for convenience.
How to compare value (example figures, not real products): a £27 tub of 270g marine collagen powder with a 9g serving gives 30 servings at 90p a day, or 10p per gram. A £24 box of 20 liquid sachets with 5g each costs £1.20 a day, or 24p per gram, more than twice as much per gram. Browse collagen powder and collagen tablets and capsules.
Does marine collagen have side effects?
Collagen is generally considered well tolerated. Versus Arthritis says it has no major side-effects, though some people report a heavy feeling in the stomach, mild diarrhoea or rashes.
Many marine collagen products add vitamins, biotin or hyaluronic acid. Add up vitamins across everything you take, and speak to your GP or pharmacist first if you're pregnant or breastfeeding, have a medical condition or take medication.
Is marine collagen halal or vegan?
Marine collagen isn't vegan, because Which? says collagen is only found in animal protein. Which? also says you can't assume collagen supplements are halal or kosher.
Check the label for certification of the finished product, including any capsule shell. For plant-based options, see vegan collagen builders, which contain other ingredients rather than collagen.
We sell the products on this page. That's our commercial interest, and it's why we show the evidence alongside them. This page is general information for adults, not personalised medical advice. Food supplements should not replace a varied, balanced diet.
Written by Andy Arshad, SupplementHQ. Last reviewed 11 October 2026.