Does Collagen Make You Gain Weight? What the Science Says

Collagen is the most abundant protein in the body, as well as one of the most important. Found in the tendons, ligaments, fat, skin, and other places, it’s a kind of scaffolding – known as the extracellular matrix – that helps the human body’s connective tissues hold together. Collagen supplements are popular for their benefits to hair, skin, and appearance in general, earning it the nickname of “fountain of youth.”

Since collagen is a protein, and a very abundant one at that, people sometimes wonder whether taking collagen can lead to weight gain. If this is a concern of yours, we’re happy to put you at ease: There’s no direct link between collagen supplementation and weight gain.

If you hear anecdotal accounts of people gaining weight while taking collagen supplements, there are good reasons for that. Recent studies have shown that supplementation with collagen peptides can support muscle mass and strength in people involved in resistance training. Since muscle tissue is more dense than fat tissue, improved muscle mass and strength can lead to some weight gain. Another study found that collagen peptide supplementation can lead to increased bone mineral density in postmenopausal women. Increases in bone density can also contribute to minor weight changes. So, in general, taking collagen supplements has no relationship to weight gain. Quite remarkably, any weight change that does occur is typically for a healthy reason. In some cases, collagen supplementation can even be connected to weight loss. (More on that below.)

Still, there are some other side effects to consider, including the possibility of water retention and bloating. Let’s take a closer look at those and see if they have any implications for your weight management.

What the research says

Collagen and water retention

Studies show that collagen does indeed have water retention abilities in the skin. Consider this study, which found that collagen supplementation significantly increased participants’ skin hydration compared to the control group. However, there’s no connection between collagen’s benefits for skin health and complications with weight management.

Collagen and bloating

When it comes to bloating, there’s good evidence to suggest that collagen supplementation is a net positive. One study examined the effects of 20 grams of daily collagen intake for otherwise healthy women who were experiencing digestive discomfort. The relevant data showed that the supplementation routine may reduce bloating and improve mild digestive symptoms – and these effects were demonstrated in the absence of other lifestyle changes, such as cultivating a healthy diet.

The argument for collagen and weight loss

There’s very limited research at this point about the possible link between collagen supplementation and weight management. However, there is some evidence to suggest an indirect relationship between collagen and effective weight management. That’s because collagen seems to have an effect on feelings of satiation and on energy expenditure, both of which help with weight management.

Collagen and satiation

Some research suggests that collagen supplements may increase satiety, otherwise known as feelings of fullness. If you feel full, you’ll naturally tend to eat less; this, in turn, can aid weight loss.

Why does collagen affect hunger in this way? Probably because it’s a protein. A recent review found that diets high in protein increase feelings of satiety by boosting the production of hormones like peptide-1 and cholecystokinin. High-protein diets can also tend to suppress a hunger hormone called ghrelin.

Another study found that upping your protein intake can increase thermogenesis, which has an impact on energy expenditure and satiety. The study also reported that such high-protein diets favor the retention of lean muscle mass. Furthermore, an even more recent study looked at the effects of gelatin, a degraded form of collagen, on satiation, as compared with casein. The study found that gelatin reduced hunger 44% more effectively than casein did.

While gelatin lacks the amino acids your body needs, and you can’t get all the protein you need from gelatin and collagen, supplements can still help with satiety and energy expenditure. One effect of increased satiety can be greater weight management potential.

Collagen and gut health

Collagen can also be good for your gut health – and that’s no small thing, since gut health influences your overall health, mental and physical. One study found that daily supplementation of 20 grams of collagen peptide improved gut health in healthy women. Collagen peptides are defined by their high levels of specific amino acids – glycine, hydroxyproline, and alanine – that are essential for your health. Another study suggested that collagen can mimic prebiotic effects and thereby promote microbiota (healthy gut bacteria) and short chain fatty acids. Taken together, these effects are hugely beneficial for gut health.

Does collagen have any side effects?

Collagen is generally safe. Aside from minor digestive symptoms, no negative side effects have been reported.