Collagen is often described as the protein that keeps your skin looking youthful. But its role goes far beyond appearance. It helps give structure to your skin, bones, joints, tendons, ligaments, and other connective tissues.
As you get older, your body naturally produces less collagen, which can contribute to changes such as less elastic skin and changes in joint and connective-tissue health. This is why collagen supplements, collagen-rich foods, and nutrients that support collagen production have become so popular.
But what does collagen actually do, and which benefits are supported by research? Here is what you need to know.
What Is Collagen?
Think of collagen as part of the body’s internal support system. It is the most abundant protein in the human body and helps give tissues such as skin, bones, tendons, ligaments, and cartilage their strength and structure.
But collagen isn’t just one type of protein. Your body makes several types, and each has a different distribution throughout the body.
Type I is the most abundant and is found mainly in skin, bones, tendons, and ligaments. Type II is the main collagen in cartilage, while Type III is commonly found alongside type I in skin, blood vessels, and other tissues.
Your body makes collagen from amino acids, but it also needs certain nutrients to build it properly. Vitamin C, for example, plays an essential role in collagen synthesis.
Together, these different types of collagen help form the structural framework that keeps tissues strong, resilient, and intact—which is why collagen matters far beyond just skin appearance.
What Are Collagen Supplements?
Collagen supplements are usually made from animal sources such as bovine, porcine, fish, or chicken collagen. Most contain collagen that has been broken down into smaller pieces called collagen peptides, also known as hydrolyzed collagen. These smaller peptides are easier to digest than intact collagen.
Once you take them, they aren’t sent directly to your skin or joints. Digestion breaks them down, and collagen-derived peptides and amino acids can then be absorbed into the bloodstream.
Powdered collagen peptides can also be mixed into everyday foods and beverages such as coffee, tea, juices, yogurt, and oatmeal.
Benefits of Collagen
So, what benefits can you actually expect from collagen?
May Improve Skin Health and Appearance
One of the most well-known benefits of collagen is its role in maintaining healthy skin.
Collagen helps provide the skin with structure and strength. As collagen production naturally declines with age, skin gradually becomes less firm and elastic, and wrinkles and other visible signs of aging can become more noticeable.
A 2023 review found that oral hydrolyzed collagen was associated with improvements in skin hydration and elasticity compared with placebo.
Similarly, a 2025 review also found that collagen supplements improved skin hydration, elasticity, and wrinkles overall. However, these benefits were no longer significant in higher-quality studies or studies without pharmaceutical-company funding, questioning their effectiveness.
Skin hydration and appearance are influenced by much more than collagen. Your skin barrier, environment, fluid intake, sun exposure, and skincare routine can all play a role.
Collagen supplements may help some aspects of skin appearance, but they should not be viewed as a guaranteed anti-aging treatment.
Potential Benefits for Hair Health
If collagen can support skin, could it help your hair too? The answer is promising, but the evidence is still early.
A 24-week trial in Korean adults with damaged hair found that 3 g daily of low-molecular-weight collagen peptides improved hair gloss, elasticity, thickness, texture, fullness, and overall appearance compared with placebo. Scalp elasticity also improved, and no treatment-related adverse events were reported.
Laboratory and animal research has also produced interesting findings. Collagen peptides increased hair follicle cell growth, activated pathways involved in hair growth, and promoted the growth phase in experimental models. However, these findings do not establish that collagen supplements increase hair growth in people.
There is also some human research involving collagen-containing supplements and hair loss.
In a 2023 study on people with androgenic alopecia, a supplement containing hydrolyzed fish collagen along with taurine, cysteine, methionine, iron, and selenium improved clinical measures when used alongside standard hair-loss treatment. Because the supplement contained several ingredients, however, the effect cannot be attributed to collagen alone.
So, while collagen may have potential benefits for hair condition and strength, it is too early to consider it a proven treatment for hair loss or hair growth. More studies testing collagen alone are needed to understand how much of a difference it can make.
May Help with Osteoarthritis
Collagen is an important component of cartilage, the tissue that cushions and supports your joints.
A meta-analysis found that oral collagen supplements improved pain and function in people with knee osteoarthritis. However, results can vary depending on the population, collagen product, dose, and study design.
The evidence extends beyond osteoarthritis. An umbrella review of 16 meta-analyses found generally favorable results for collagen supplementation across several musculoskeletal outcomes, including osteoarthritis, muscle, and bone-related measures. However, findings for oral and cardiometabolic health were mixed.
Collagen should not be considered a replacement for appropriate medical evaluation or treatment when persistent or severe joint pain has an underlying medical cause.
May Support Bone, Muscle, and Connective Tissue Health
Collagen isn’t just about skin. It is also an important part of the tissues that keep your body strong and supported, including bones, tendons, and ligaments. It also contributes to the structural framework surrounding muscles.
A 2026 umbrella review found generally favorable results for bone and muscle-related outcomes, while a 2025 meta-analysis reported improvements in some measures of bone density, bone turnover, and muscle performance. Benefits were also seen when collagen was combined with calcium and vitamin D, although results varied across studies, particularly for bone density.
Tendons have also received attention. Emerging research suggests that taking collagen alongside resistance or plyometric training may improve certain measures of tendon structure. However, the studies are still relatively small, so it’s too early to know how meaningful these effects are in everyday life.
Bone health may be particularly relevant after menopause, when changes in bone remodeling can contribute to declining bone mineral density.
In a 12-month trial involving 131 postmenopausal women with reduced bone mineral density, specific collagen peptides increased bone mineral density at the spine and femoral neck compared with placebo. More research is needed to determine how consistently collagen supplements can benefit bone health.
Still, collagen shouldn’t be treated as a substitute for the basics. Collagen is not a complete protein, so it shouldn’t replace high-quality protein foods. Adequate protein, calcium, vitamin D, resistance exercise, and other established habits remain important for keeping bones, muscles, and connective tissues healthy.
What About Collagen and Gut Health?
Collagen is sometimes promoted as a supplement that can “heal” or “repair” the gut, but there isn’t enough high-quality human evidence to support these claims.
Collagen peptides provide amino acids that the body uses for many functions, including maintaining connective tissues. However, this doesn’t mean that taking collagen supplements can repair a damaged gut lining, treat “leaky gut,” or improve digestive disorders.
If your goal is better gut health, focus first on dietary fiber, a variety of plant foods, adequate fluids, and a balanced overall diet rather than relying on collagen alone.
What Causes Collagen to Decrease? And Can You Prevent It?
Your body doesn’t suddenly stop making collagen as you get older. Instead, collagen production gradually declines, while the breakdown of existing collagen can increase.
Age is one factor, but it isn’t the only one. Excessive UV exposure, smoking, poor overall nutrition, excessive alcohol consumption, and oxidative stress can also contribute to collagen breakdown or interfere with normal collagen production.
UV exposure is particularly important for skin. Repeated UV exposure can increase collagen degradation and reduce collagen production, contributing to changes associated with premature skin aging.
Smoking can affect collagen in a similar way. In one human study, smokers had lower production of type I and III collagen and higher levels of a collagen-degrading enzyme compared with nonsmokers.
Sugar plays a role too. High sugar availability can promote glycation, a process in which sugars react with proteins and form compounds called advanced glycation end products (AGEs). Collagen is particularly susceptible because it is a long-lived protein. As AGEs accumulate, they can alter collagen’s structure and mechanical properties, making collagen tissues less flexible.
Excessive alcohol consumption may affect collagen and skin health as well. Alcohol can increase oxidative stress and has been associated with premature skin aging. A 2025 study of 459 people undergoing lumbar fusion found that alcohol abuse was associated with thinner skin and changes in the deeper dermal layer, suggesting dermal tissue degradation.
You can’t prevent the natural changes that come with aging.
But understanding what can accelerate collagen breakdown gives you something more useful: ways to protect the collagen your body still produces. Limiting excessive sun exposure, avoiding smoking, eating a balanced diet, and getting enough protein and essential nutrients can help support overall skin and connective-tissue health.
How to Support Collagen Production
You do not need to rely entirely on supplements to support your body’s collagen production.
Focus on the basics:
Eat enough protein: Your body needs amino acids to build collagen and other proteins.
Get enough vitamin C: Vitamin C is essential for normal collagen synthesis.
Eat a varied diet: Fruits, vegetables, legumes, dairy, eggs, seafood, and other whole foods provide nutrients involved in maintaining healthy tissues.
Protect your skin from excessive UV exposure: UV radiation contributes to collagen breakdown and premature skin aging.
Avoid smoking: Smoking is associated with impaired collagen production and increased collagen breakdown.
Safety and Side Effects
Collagen supplements appear to be generally well tolerated in clinical studies. A recent review suggests that hydrolyzed collagen may improve skin hydration, elasticity, and wrinkles and was generally well tolerated. However, most studies had a high risk of bias, so larger, higher-quality, longer-term trials are needed to confirm its benefits and safety.
That said, a collagen supplement isn’t automatically suitable for everyone. Products can differ in their collagen source, ingredients, dose, and overall formulation. Some may also contain additional ingredients that you may be allergic or sensitive to.
The source matters too. Collagen supplements are usually made from fish, cattle, pigs, or other animal sources, so check the label carefully if you have a food allergy or avoid certain animal-derived ingredients. They are also not suitable for vegetarians or vegans.
And if you’re taking collagen for a specific health concern, remember that a supplement shouldn’t replace appropriate medical treatment.
Learn more: 12 Vegetarian foods that support collagen production
Final Thoughts
Collagen is much more than a beauty protein. It provides structure and support to your skin, bones, cartilage, tendons, ligaments, and other connective tissues.
Collagen supplements may offer benefits for skin hydration and elasticity, and research is also exploring their potential role in joint, bone, and musculoskeletal health. But the evidence is mixed, particularly when higher-quality studies are considered.
The most reliable way to support your body’s natural collagen production is still to focus on the fundamentals: adequate protein, vitamin C-rich foods, a balanced diet, sun protection, and healthy lifestyle habits.