Collagen supplements may modestly improve skin hydration and elasticity, but the evidence for other claims, such as stronger hair, nails, joints or bones, is limited, and the body doesn’t send swallowed collagen straight to your skin. Collagen is broken down in digestion into amino acids and small peptides, like any other protein. A 2021 meta-analysis of 19 randomized trials, with 1,125 participants who were mostly women, found that hydrolyzed collagen improved skin hydration, elasticity and wrinkles compared with placebo, though many trials in this field are small and funded by supplement makers. Collagen supplements are generally safe, but they’re not regulated like medicines, they’re expensive, and the basics of sun protection, not smoking, enough protein and plenty of fruit and vegetables matter more for skin.
What is collagen?
Collagen is the most abundant protein in the body. It gives structure to skin, tendons, ligaments, bones and cartilage. The body makes its own collagen from amino acids, especially glycine, proline and hydroxyproline, using vitamin C as an essential helper. Collagen production slows with age, and sun exposure and smoking speed up its breakdown, which is one reason skin wrinkles and loses firmness over time.
What’s in collagen supplements?
Most supplements contain hydrolyzed collagen, also called collagen peptides, made from the skin and bones of cows, pigs or fish. They come as powders, capsules, gummies and drinks, and doses typically range from about 2.5 to 10 g a day. Collagen is not a complete protein, as it lacks the essential amino acid tryptophan, so it’s not a good replacement for other protein foods.
What the evidence says
Skin
The meta-analysis above found improvements in skin hydration, elasticity and wrinkle depth after about 90 days of taking hydrolyzed collagen. The effects were modest, and many trials were small, short and funded by industry, which can make results look better than they are. Collagen won’t undo sun damage, and it’s no substitute for daily sunscreen. Our guide to foods for healthy skin covers diet and skin more broadly.
Joints
Some small experiments suggest collagen may slightly reduce joint pain in people with osteoarthritis or in athletes, but the evidence is mixed and of low quality. Losing excess weight and staying active have stronger evidence for joint health.
Bones
There’s early evidence that collagen peptides may support bone density in postmenopausal women when combined with calcium and vitamin D, but this needs more evidence. Calcium, vitamin D, protein and weight-bearing exercise remain the foundations of bone health, as the NHS explains.
Hair, nails and gut
There’s very little good evidence that collagen strengthens hair or nails, or that it heals the gut, despite common marketing claims.
Safety
Collagen supplements are generally well tolerated. Some people report mild digestive upset or a feeling of fullness. Points to check:
- Allergies: collagen made from fish, eggs or shellfish isn’t suitable for people with those allergies. Check the source.
- Not vegetarian or vegan: collagen comes from animals. “Vegan collagen boosters” contain nutrients that support the body’s own collagen production, not collagen itself.
- Quality: supplements are regulated as foods, not medicines, so quality varies. The US Food and Drug Administration explains that it doesn’t approve dietary supplements for safety and effectiveness before they’re sold. Choose products that have been independently tested.
- Added ingredients: collagen drinks and gummies can contain added sugar, sweeteners and other ingredients.
- Pregnancy and breastfeeding: there’s little safety information, so ask your doctor first.
How to support your body’s own collagen
- Eat enough protein from a variety of sources, such as fish, poultry, eggs, dairy, beans, lentils and tofu. Our guide to high-protein meals has ideas.
- Get plenty of vitamin C from fruit and vegetables such as peppers, citrus, kiwi, berries and broccoli. Vitamin C is needed to form collagen, as the US National Institutes of Health explains. Our list of vitamin C foods has more.
- Protect your skin from the sun with sunscreen, shade and clothing.
- Don’t smoke, which speeds up collagen breakdown.
- Eat a varied diet with zinc and copper from nuts, seeds, whole grains, shellfish and meat.
Food sources of collagen
Bone broth, chicken skin, fish skin and gelatin-rich cuts such as oxtail contain collagen, though amounts vary. They’re not necessary; your body can make collagen from the amino acids in any protein-rich diet.
Who might consider collagen?
Collagen is most often used by adults interested in skin aging, and by some athletes and older adults with joint discomfort. For people who don’t eat much protein, it adds some, but a balanced protein-rich diet does more, because collagen lacks tryptophan and is low in several other essential amino acids. People with kidney disease, those on protein-restricted diets, and anyone with allergies to the animal source should check with their doctor first.
Are collagen supplements worth it?
If you’re interested in trying collagen for skin, the evidence suggests a possible modest benefit with low risk, but it’s an optional extra. Spending the money on sunscreen and a protein- and vegetable-rich diet is likely to give more value. If you have joint pain, talk to your doctor or a physiotherapist about treatments with stronger evidence.
Common questions
How long does collagen take to work?
In most of the experiments, skin effects were measured after 8 to 12 weeks of daily use.
Is marine collagen better than bovine collagen?
There’s no good evidence that one source is better for skin. Choose based on your diet, allergies and preference.
Can I get the same benefit from bone broth?
Bone broth contains some collagen, but amounts vary widely and haven’t been tested in the same way as supplements. Our article on whether soup is healthy covers bone broth.
Does collagen help with cellulite or stretch marks?
There’s very little good evidence for either. Staying active, keeping a stable weight and protecting your skin from the sun are more useful.
When should I take collagen?
Timing doesn’t seem to matter much. Some people stir it into coffee, smoothies or porridge in the morning; the main thing is consistency if you choose to take it.
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
