Collagen supplements: what they do and how much

What is collagen good for, and what does collagen powder do?

Collagen powder is a protein supplement, and your body digests it much like any other protein. Inside your body, collagen is what gives skin, tendons, cartilage and bone their structure, and it is the most abundant protein in mammals (Ricard-Blum, 2011). Supplements are made from cattle, pigs, chickens or fish. Hydrolysed collagen, also sold as collagen peptides or collagen hydrolysate, has been cut by enzymes into short chains of amino acids, which is why the powder dissolves in a drink.

What you swallow doesn't reach your skin as collagen. Your gut breaks it into amino acids and fragments two or three amino acids long, and some of those fragments show up in the blood for a few hours: a 2017 study found 17 different collagen-derived peptides in people's blood after a dose. It followed the fragments into skin in mice, not in people, so whether they act on human skin or joints is still an open question.

In Great Britain, no health claim for collagen is authorised. Claims that collagen helps maintain joints, or keeps skin firm and elastic, have been assessed and rejected. The authorised claim belongs to vitamin C: vitamin C contributes to normal collagen formation for the normal function of skin, with matching claims for bones, cartilage, gums, teeth and blood vessels. Your body makes its own collagen, and the NHS says you should be able to get all the vitamin C you need from your diet.

Is collagen good for you?

For most healthy adults, collagen powder is a safe but limited source of protein. Collagen is rich in glycine, proline and hydroxyproline but has no tryptophan, one of the amino acids your body can't make, so it counts as an incomplete protein (Paul and colleagues, 2019). When Canadian researchers gave older women 30 g of whey or 30 g of collagen twice a day for six days, whey raised the rate at which their muscles built new protein and collagen didn't (Oikawa and colleagues, 2020). Collagen can add to your protein intake, but it shouldn't replace protein from food.

Does collagen help with weight loss?

There's little evidence that it does, and no authorised claim says so. Most of the research is in animals: a 2026 review pooled 19 studies in rodents fed high-calorie diets and found that collagen peptides reduced weight gain, but it rated the certainty of that evidence as very low and said the effect in humans has barely been studied (Bischof and colleagues). In people, a single 12-week Korean trial in 81 overweight adults reported less body fat with a peptide made from skate skin than with a placebo.

The other argument is that protein is filling. In a 2009 Dutch lab study, 24 young adults ate less at lunch after a breakfast made with gelatin, which is also made from collagen, than after breakfasts made with casein, soy or whey, though the study only tested one meal (Veldhorst and colleagues). In Great Britain, claims that protein helps you feel fuller or manage your weight have been assessed and not authorised, and an NHS kidney service notes that, as a nation, we already tend to eat more protein than we need. Our protein calculator gives a sensible daily range for your weight and activity.

If weight is your concern, our guide to appetite suppressants in the UK covers what has evidence, including the prescription options to discuss with a GP.

Does collagen powder work for skin and joints?

The results depend partly on who paid for the trial. For skin, a 2023 meta-analysis of 26 randomised trials with 1,721 participants found that hydrolysed collagen improved skin hydration and elasticity compared with placebo, with effects showing after eight weeks or more (Pu and colleagues). The authors also found several sources of bias in the trials. A 2025 meta-analysis of 23 trials then split the results by who paid for them. Trials funded by companies reported better hydration, elasticity and wrinkles; trials without that funding found no effect, and neither did the high-quality trials. Its authors concluded that there is currently no clinical evidence to support collagen supplements for skin ageing (Myung and Park).

For joints, a 2025 meta-analysis of 11 trials in 870 people with knee osteoarthritis found lower pain and better function scores with collagen than with placebo, but the results varied widely from trial to trial (Simental-Mendía and colleagues). In a 24-week trial at Penn State University, 147 student athletes with activity-related joint pain took 10 g of collagen hydrolysate or a placebo each day. The collagen group reported less pain on several measures, but only 97 of the 147 could be included in the analysis (Clark and colleagues, 2008). Osteoarthritis is a medical condition, so if your joints hurt, see your GP.

Does collagen help hair growth?

There's very little evidence that it does. A 2023 systematic review in JAMA Dermatology looked at 30 studies of supplements for hair loss, and collagen on its own wasn't among the supplements it found evidence for (Drake and colleagues). The one trial we found that measured hair directly gave 114 Korean women with thinning hair 1 g a day of a fish collagen peptide or a placebo for 24 weeks. The collagen group ended with thicker hair strands, but the trial measured thickness rather than growth, and two of its authors work in a health-food company's research department (Hwang and colleagues, 2026).

Hair shedding has many causes, including stress, illness, weight loss and iron deficiency, and the NHS advises seeing a GP if you're worried. Our guide to biotin for hair and nails looks at another popular hair supplement.

How much collagen should you take per day?

There's no official recommended amount for women or men, because collagen isn't an essential nutrient. Trials have used 2.5 to 15 g a day (Paul and colleagues, 2019): 10 g in the athletes' joint trial, 5 g in a 12-month bone trial in postmenopausal women, and 15 g alongside strength training in a German trial in older men (Zdzieblik and colleagues, 2015). Nothing in the evidence points to a different amount for women. If you're asking because of menopause, see the FAQ below and our perimenopause supplements guide.

How much marine collagen per day, and is 1,000 mg enough?

The fish collagen trials in the 2023 skin review used 1 to 10 g a day, so 1,000 mg (1 g) matches the lowest fish dose tested. It is also below the 2.5 to 15 g a day reviewed above. Whether it is enough isn't known: no amount is recommended, and the independent skin trials found no effect at the doses tested (Myung and Park).

How long does collagen powder take to work?

In the 2023 skin meta-analysis, trials lasted 2 to 12 weeks, and effects appeared only in those of eight weeks or more. The athletes' joint trial ran for 24 weeks and the bone trial for 12 months. In the 2025 analysis, though, the independent skin trials found no effect.

Can you take too much collagen?

There's no UK upper limit for collagen, and side effects in trials have been uncommon. A 2026 review of 25 skin trials found collagen generally well tolerated, though it rated most of the trials at high risk of bias (Bassila and colleagues), and the 12-month bone trial reported no adverse events (König and colleagues, 2018). Collagen does count towards your total protein, which matters if you've been told to limit protein, and larger amounts raise the oxalate in your urine, as the kidney section below explains.

What are the different types of collagen?

The collagen family has 28 members (Ricard-Blum, 2011), and supplements are usually described by three of them: types I, II and III. Type 1 collagen is the most abundant, making up 85 to 90% of the collagen in skin (Wang, 2021).

Type 1 and 3 collagen is the mix on bovine and porcine products. Type 2 collagen supplements are a separate group, and one form, undenatured type II (UC-II), is taken in milligrams rather than grams. In a 180-day trial in India, 191 people with knee osteoarthritis took 40 mg a day of UC-II, glucosamine with chondroitin, or a placebo. Pain, stiffness and function scores improved more with UC-II than with placebo, but its maker sponsored the trial and two authors work there (Lugo and colleagues, 2016).

Bovine collagen vs marine collagen: which is better?

Neither marine nor bovine collagen has been shown to be better than the other. Marine collagen is made from fish and bovine collagen from cattle, which is the main difference between them in practice. The benefits listed for each rest on the same skin and joint trials above, with the same limits.

In the 2023 skin meta-analysis, nine trials didn't say which source they used. Elasticity results didn't differ by source. Fish collagen trials showed the biggest effect on hydration, but those were separate trials of different products rather than head-to-head comparisons, and the funding question applies to them too. You'll see claims that marine collagen is absorbed much better; we couldn't find good human evidence behind the figures quoted.

Marine collagen comes from fish, one of the 14 allergens UK food businesses must declare, so avoid it if you have a fish allergy. Bovine collagen comes from cattle, so it won't suit you if you avoid beef. Neither is vegetarian or vegan.

Which foods contain collagen?

Collagen rich foods are animal connective tissue. A US analysis of national diet survey data (Paul and colleagues, 2019) listed the main dietary sources:

• Beef, pork, veal, lamb and game
• Chicken, turkey and other poultry
• Seafood
• Sausages, frankfurters and luncheon meats

It estimated that collagen protein intake varied from 3 g a day to 23 g a day for people who ate a lot of sausages and similar products. Gelatine desserts, aspic and broths made from bones or cartilage also contain collagen, but it isn't hydrolysed, so they are unlikely to give reliable amounts of collagen peptides.

No food is a collagen booster in the sense of delivering collagen to your skin, because eaten collagen is digested into amino acids like any protein. To get collagen naturally, give your body what it builds its own from: protein foods, which the NHS lists as beans, pulses, fish, eggs, meat and other protein foods, and vitamin C, which contributes to normal collagen formation for the normal function of skin. Good sources include citrus fruit, peppers, strawberries, blackcurrants, broccoli and potatoes.

Collagen powder side effects and who should be careful

The side effects with the best evidence behind them are allergic reactions and, for people prone to kidney stones, a rise in urinary oxalate. Bloating, constipation and weight gain are less well studied.

Marine collagen and bovine collagen side effects

Allergy is the clearest risk, and it follows the animal. A 2020 case report describes a 9-year-old girl with fish allergy who had anaphylaxis, a severe allergic reaction, after two gummy tablets containing fish collagen, so avoid marine collagen if you have a fish allergy. Bovine type I collagen is a major allergen in bovine gelatin allergy, so bovine collagen isn't suitable if you're allergic to gelatin. A small 2000 study found little cross-reactivity between fish and bovine gelatin, but some people react to both, so ask your GP or an allergy specialist before trying either.

Collagen side effects on the kidneys

Trials in people with healthy kidneys haven't shown kidney harm, and the 12-month bone trial found no clinically relevant change in kidney blood tests. Collagen is rich in hydroxyproline, though, which the body partly turns into oxalate, and oxalate contributes to calcium oxalate kidney stones. When volunteers' diets included 30 g of gelatin rather than 30 g of whey protein, the oxalate in their urine was 43% higher. Single doses of 5 g and 10 g of gelatin raised urinary oxalate, while 1 g and 2 g did not (Knight and colleagues, 2006). The NHS also lists a high-protein, low-fibre diet among the things that make kidney stones more likely to come back.

Can collagen cause constipation or bloating?

Neither stands out as a side effect in the trials and reviews above, and we couldn't find good evidence either way. The only study we found that looked directly at bloating was run with a collagen manufacturer and had no placebo group, and only 14 of its 40 participants completed it, so it tells you little (Abrahams and colleagues, 2022). If your digestion changes after you start collagen, try a smaller serving and check what else is in the tub. See your GP or pharmacist if it doesn't settle.

Can collagen cause weight gain?

Collagen is a protein, so it provides calories like other protein, about 4 per gram (NHS My Health London), which means 10 g of collagen provides up to about 40. Whether that matters for your weight depends on everything else you eat, and we found no review that lists weight gain as a side effect. The weight loss section above covers what the research shows.

Can you take collagen while pregnant?

There's no research to go on: we found no trials of collagen supplements in pregnancy or breastfeeding. The NHS advice in pregnancy is a healthy, varied diet plus folic acid and vitamin D supplements, and no vitamin A supplements or cod liver oil. Ask your midwife or GP before taking anything else.

Where Natura fits

Daily Collagen, a 13 g scoop of hydrolysed grass-fed bovine collagen peptides (types I and III) to stir into coffee, soup or water, is in the Natura cabinet (coming soon) with our single bottles. The Skin Pack pairs it with Daily Zinc (15 mg), and zinc contributes to the maintenance of normal skin. We make no health claim for the collagen itself, because none is authorised.