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Collagen is the main protein in the human body, found in skin, tendons, ligaments, and other connective tissues (1).

28 types of collagen have been identified, with types I, II, and III being the most abundant in the human body, making up 80–90% of total collagen (1, 2).

Types I and III are mainly found in your skin and bones, while type II is primarily found in the joints (3, 4).

Your body produces collagen naturally, but supplements have been marketed to help improve skin elasticity, promote joint health, build muscle, burn fat, and more.

This article discusses whether collagen supplements work based on scientific evidence.

Most collagen supplements are sourced from animals, particularly pigs, cows, and fish (5).

The composition of supplements vary, but they typically contain collagen types I, II, III, or a mixture of the three.

They can also be found in these three main forms (6):

  • Hydrolyzed collagen. This form, also known as collagen hydrolysate or collagen peptides, is broken down into smaller protein fragments called amino acids.
  • Gelatin. The collagen in gelatin is only partially broken down into amino acids.
  • Raw. In raw — or undenatured — forms, the collagen protein remains intact.

Of these, some research shows that your body may absorb hydrolyzed collagen most efficiently (7, 8).

That said, all forms of collagen are broken down into amino acids during digestion and then absorbed and used to build collagen or other proteins your body needs (9).

In fact, you don’t need to take collagen supplements to produce collagen — your body does this naturally using amino acids from whichever proteins you eat.

Yet, some studies suggest that taking collagen supplements may enhance its production and offer unique benefits (10).

Summary

Collagen supplements are typically sourced from pigs, cows, or fish and may contain types I, II, or III collagen. Supplements are available in three main forms: hydrolyzed, raw, or as gelatin.

Some evidence indicates that collagen supplements may reduce wrinkles and alleviate joint pain.

Skin

Collagen types I and III are major components of your skin, providing strength and structure (11).

Though your body produces collagen naturally, studies suggest the amount in skin may decrease by 1% each year, which contributes to aging skin (12).

Early research shows that taking supplements may boost collagen levels in your skin, reduce wrinkles, and improve skin elasticity and hydration (13, 14, 15, 16).

In a study in 114 middle-aged women, taking 2.5 grams of Verisol — a brand of hydrolyzed collagen type I — daily for 8 weeks reduced wrinkle volume by 20% (17).

In another study in 72 women ages 35 years or older, taking 2.5 grams of Elasten — a brand of hydrolyzed collagen types I and II — daily for 12 weeks reduced wrinkle depth by 27% and increased skin hydration by 28% (18).

Though early research is promising, more research is needed to determine how effective collagen supplements are for skin health and which supplements work best.

Also, keep in mind that some of the available studies are funded by collagen manufacturers, which is a potential source of bias.

Joints

Collage type II is predominately found in cartilage — the protective cushioning between joints (4).

In a common condition known as osteoarthritis (OA), the cartilage between joints wears away. This may lead to inflammation, stiffness, pain, and reduced function, especially in the hands, knees, and hips (19).

A handful of studies suggest that various types of collagen supplements may help relieve joint pain related to OA.

In two studies, 40 mg of UC-II — a brand of raw type-II collagen — taken daily for up to 6 months reduced joint pain and stiffness in individuals with OA (20, 21).

In another study, taking 2 grams of BioCell — a brand of hydrolyzed type-II collagen — daily for 10 weeks reduced scores of joint pain, stiffness, and disability by 38% in individuals with OA (22).

Notably, the manufacturers of UC-II and BioCell funded and helped conduct their respective studies, and this may influence the study results.

On a final note, collagen supplements may also help relieve joint pain associated with exercise and rheumatoid arthritis, though more research is needed (23, 24, 25).

Summary

Early studies suggest that collagen supplements may help reduce wrinkles and relieve joint pain in individuals with OA.

Though the potential benefits are promising, there is not much research on the effects of collagen supplements on bone, muscle, and other areas.

Bone health

Bone is made mostly of collagen, especially type I (26).

For this reason, collagen supplements are purported to help guard against osteoporosis — a condition in which bones become weak, brittle, and more likely to fracture (27).

However, many of the studies supporting this benefit have been carried out in animals (28, 29).

In one human study, 131 postmenopausal women taking 5 grams of a hydrolyzed collagen supplement called Fortibone daily for 1 year experienced a 3% increase in bone density in the spine and a nearly 7% increase in the femur (30).

Nevertheless, while some studies suggest collagen supplements may improve bone mass and prevent bone loss, more in-depth studies in humans are needed.

Building muscle

Like all protein sources, collagen supplements likely support muscle growth when combined with resistance training (31).

In a study in 53 older men, those who took 15 grams of hydrolyzed collagen after resistance training for 3 months gained significantly more muscle than those who took a non-protein placebo (32).

In another study in 77 premenopausal women, collagen supplements had similar effects when compared with a non-protein post-workout supplement (33).

Essentially, these results suggest that collagen supplements may work better than no protein at all after training. However, whether collagen supplements are superior to other sources of protein for muscle building has yet to be determined.

Other benefits

As collagen comprises much of the body, taking it as a supplement has numerous potential benefits.

However, many have not been studied thoroughly. Only a few studies suggest collagen supplements may work for (34, 35, 36, 37):

Overall, more evidence is needed in these areas.

Summary

Though current research is promising, there is minimal evidence supporting collagen supplements for bone health, muscle building, and other benefits.

Here are some recommended dosages based on the available research:

  • For skin wrinkles. 2.5 grams of hydrolyzed collagen type I and a mixture of types I and II have demonstrated benefits after 8 to 12 weeks (17, 18).
  • For joint pain. 40 mg of raw type-II collagen taken daily for 6 months or 2 grams of hydrolyzed type-II collagen for 10 weeks may help reduce joint pain (20, 21, 22).
  • For bone health. Research is limited, but 5 grams of a hydrolyzed collagen sourced from cows helped increase bone density after 1 year in a single study (30).
  • For muscle building. 15 grams taken within 1 hour after resistance training may help build muscle, though other protein sources are likely to have similar effects (32, 33).

Collagen supplements are generally safe for most people. However, mild side effects have been reported, including nausea, upset stomach, and diarrhea (38).

As collagen supplements are generally sourced from animals, most types are unsuitable for vegans or vegetarians — though there are exceptions.

Additionally, they may contain allergens, such as fish. If you have an allergy, be sure to check the label to avoid any collagen derived from that source.

On a final note, keep in mind that you can also obtain collagen from food. Chicken skin and gelatinous cuts of meat are excellent sources.

Summary

Collagen doses ranging from 40 mg to 15 grams are potentially effective and appear to have minimal side effects.

Collagen supplements have several purported benefits.

The scientific evidence for using collagen supplements to reduce wrinkles and relieving joint pain associated with osteoarthritis is promising, but higher quality studies are needed.

Collagen supplements have not been studied much for muscle building, improving bone density, and other benefits. Thus, more research is needed in all areas.

If you want to try collagen, you can buy supplements in local specialty stores or online, but be sure to discuss this with your healthcare provider first.