Can Collagen Supplements Help You Lose Weight? Here’s What Researchers Found

Collagen is a buzzy supplement for a variety of health concerns, from skin aging to joint pain. Now, new research has found that it might also support healthy weight loss. 

A study recently presented at the European Congress on Obesity and published in Nutrients revealed that people who consumed a collagen-enriched protein bar twice a day lost double the weight of a control group who did not consume collagen. 

“The thought of eating more—not less—to support weight loss sounds amazing,” obesity medicine expert Su-Nui Escobar, DCN, RDN, FAND, told Health. “If it really works, it seems like a no-brainer to try.”

But the study has some major limitations, making it too early to know for sure whether a daily collagen bar does really work for weight loss. Here’s a more in-depth look at the research.

Collagen is the most abundant protein in the human body, providing structure to skin, bones, muscles, and connective tissue. When taken as a supplement, it typically derives from the bones of land mammals or fish. In the new study, protein bars were enriched with 10 grams each of bovine collagen specially treated to expand and retain water in the stomach.

However, other ingredients were added to make the bars more palatable. Each bar also contained a dark chocolate coating made with cocoa sweetener, vegetable dietary fiber, maltitol syrup, soy nuggets, soy protein isolate, chopped cocoa cookie, sunflower oil, and sorbitol syrup. The bars supplied 90 calories total, including 8.8 grams of protein, 7.2 grams of carbohydrates, 3.2 grams of fat, and 2.5 grams of fiber.

The researchers recruited 64 people (32 women and 32 men) aged 20 to 65 with overweight or obesity.

For 12 weeks, one group consumed two collagen-enriched protein bars. They ate their first bar 45 minutes before lunch and their second bar 45 minutes before dinner, both accompanied by 250 milliliters of water. A control group, meanwhile, consumed 250 milliliters of water 45 minutes before lunch and dinner but was not given bars.

At the end of 12 weeks, those who ate the collagen protein bars:

• Lost more weight. Participants in this group lost an average of 6.6 pounds, while those who didn’t eat them lost only an average of 3.3 pounds. 
• Showed more improvement in certain health-related measures. Participants on the protein bar regimen also had more significant decreases in blood pressure, waist circumference, and markers of fatty liver.
• Retained muscle mass. The group that lost more weight did so without losing much muscle. “Weight loss is usually accompanied by a loss of lean mass (muscle mass), but our results indicate that the supplementation with these bars is able to maintain the lean mass without accompanying with extra exercise,” study author Fermín Milagro, PhD, a researcher at Spain’s University of Navarra, told Health.

It’s likely that the collagen’s absorbency allowed it to expand in the stomach, promoting feelings of satiation.

Beyond this, Milagro said the reasons for collagen’s weight loss and other health effects might be twofold.

First, collagen may promote changes in the gut microbiome. Because collagen is difficult to digest, Milagro said it survives digestion all the way to the large intestine. Here, it becomes “food” for gut microbiota, creating short-chain fatty acids that have been linked to reductions in inflammation and lower rates of obesity. Second, collagen may be more “thermogenic” than other proteins, meaning it burns more calories.

In a world of expensive GLP-1 medications, a low-cost supplement for weight management sounds like a godsend—but experts say this research doesn’t necessarily mean collagen is the answer for doubling your weight loss goals.

The research had some notable limitations. Aside from its small sample size of just 64 people, it didn’t track weight loss in the long term. “This was only a 12-week study,” noted bariatric surgeon Kyle Thompson, MD. “Most people are looking to lose weight and maintain that weight loss, so we need longer-term studies.” Thompson also pointed out that, though the results were considered statistically significant, the difference in weight between groups was only about one BMI point—a small amount compared to what most people with obesity would like to lose.

Because the bars contained multiple ingredients and nutrients, it’s also not totally clear whether collagen was the true stimulus behind decreased weight. “It makes me wonder if the real benefit came from having a low-calorie protein bar with fiber—something we already know can support weight loss—rather than the collagen itself,” said Escobar.

Finally, it’s worth noting that Viscofan, a company that makes collagen-based meat casings, funded the Nutrients study. While Thompson said this doesn’t negate its findings, it’s a sign to take results with a grain of salt. “Unfortunately, no matter how good a study is, sometimes our biases can affect the results.”

According to Thompson, there are few risks associated with taking a collagen supplement, so trying out the 20-gram dosage for weight loss is a relatively low-stakes proposition.

Then again, Escobar said it’s impossible to replicate the bars’ ingredients and formula on your own because the ones used in the study aren’t available for public consumption. Plus, the collagen in the study was specially created to retain extra water—another characteristic you won’t find in any old OTC collagen pill or powder. (However, the collagen used in the study is available to retailers in Europe.)

If you do want to try collagen, be sure to run it by your doctor or dietitian first. Once you’ve gotten their all-clear, Thompson recommends looking for third-party tested supplements and sticking to recommended dosages. He also urged caution if you have food allergies. Many collagen supplements are made with protein from marine animals, making them dangerous for people with shellfish allergies.

Ultimately, though the Nutrients study may spark more research on collagen and body weight, it’s probably too early to hit the supplement aisle with high hopes of shedding pounds. For now, Thompson encouraged pursuing other tried-and-true methods while keeping an open mind. “Obesity is an incredibly complicated disease to treat, and I tell people we use any tool that we have in our toolbox to help you with obesity,” he said.