Collagen has long been promoted for its potential benefits in skin health, joint function, and overall vitality. Recently, it has entered the spotlight for a different reason—its possible connection to weight loss. A new study presented at the European Congress on Obesity and published in the journal Nutrients has suggested that collagen-enriched protein bars might aid weight loss. Participants who consumed these bars twice daily reportedly lost more weight than those who didn’t. While the findings have generated interest, several limitations of the study indicate that it is too soon to make definitive claims.
What Is Collagen?
Collagen is the most abundant protein in the body and plays a structural role in skin, bones, muscles, and connective tissues. As people age, collagen levels decline, which can lead to wrinkles, weaker joints, and reduced muscle mass. Supplements are typically derived from bovine (cow), porcine (pig), or marine (fish) sources and are available in powders, capsules, or infused into food products like bars and drinks.
In the recent study, researchers used protein bars containing 10 grams of bovine collagen, designed to expand in the stomach and increase feelings of fullness. The bars were consumed twice daily, each with 250 milliliters of water—once before lunch and once before dinner.
Inside the Study
The study involved 64 adults—32 men and 32 women—aged 20 to 65, all classified as overweight or obese. Participants were divided into two groups. One group consumed two collagen-enriched protein bars daily, while the control group only consumed water before meals, with no supplement or dietary intervention.
After 12 weeks, the group consuming collagen bars lost an average of 6.6 pounds. In contrast, the control group lost an average of 3.3 pounds. Additionally, the collagen group saw improvements in blood pressure, waist circumference, and fatty liver markers. Importantly, their muscle mass was largely preserved despite the reduction in body weight.
These findings indicate that collagen supplementation may support weight management in certain contexts, possibly due to its unique properties when ingested.
How Could Collagen Influence Weight?
There are several theories behind the observed effects. The collagen used in the study was specially engineered to expand and retain water in the stomach. This may have increased satiety, leading participants to eat less at subsequent meals. By promoting a feeling of fullness, collagen could help reduce overall calorie intake.
Another hypothesis involves the gut microbiome. Because collagen is relatively hard to digest, it may reach the large intestine intact, where it can serve as a nutrient source for gut bacteria. This interaction could generate short-chain fatty acids, which are associated with reduced inflammation and improved metabolic health.
Collagen might also be more thermogenic than other proteins, meaning the body could use more energy to digest and process it. This thermogenic effect, if confirmed, could help burn more calories over time.
What Was in the Protein Bars?
Each collagen-enriched bar provided 90 calories and contained a blend of ingredients beyond collagen. These included dark chocolate coating, cocoa sweetener, vegetable fiber, soy nuggets, soy protein isolate, chopped cookie, sunflower oil, and sugar alcohols like maltitol and sorbitol.
Nutritionally, the bars had 8.8 grams of protein, 7.2 grams of carbohydrates, 3.2 grams of fat, and 2.5 grams of fiber. This composition is consistent with many existing protein bars that aim to support satiety and muscle preservation. It raises the question: was it the collagen, the fiber, the protein content, or the overall low-calorie nature of the bars that supported weight loss?
Study Limitations
Despite the promising results, the study had several limitations. First, it included only 64 participants, which is a small sample size for drawing broad conclusions. Second, the study only lasted 12 weeks. Weight loss is often difficult to maintain over time, and short-term changes do not always reflect long-term outcomes.
Another concern is the lack of clarity about whether collagen was the specific factor behind the benefits. Because the bars included a combination of low-calorie ingredients with protein and fiber—both already associated with weight loss—it’s hard to isolate collagen’s exact role.
Additionally, the study was funded by a company that manufactures collagen products, which may introduce bias. While industry funding does not automatically discredit research, it does warrant scrutiny and independent verification through larger, unbiased studies.
What Experts Advise
Though the findings are intriguing, health professionals advise caution. Collagen supplements are generally considered safe and well-tolerated. However, not all collagen supplements are the same. The bars used in the study were specially formulated to expand in the stomach and are not available on the consumer market. This makes it difficult to replicate the results with over-the-counter powders or capsules.
For those interested in trying collagen, it’s important to consult a healthcare provider first—especially if there are allergies or sensitivities involved. Some collagen supplements are derived from marine sources and can pose risks to individuals with shellfish allergies.
Moreover, experts emphasize that collagen supplements should not replace foundational weight management strategies. Diet, physical activity, sleep, and behavioral habits remain central to long-term success. Supplements may help support these efforts but are unlikely to act as a standalone solution.
The Bottom Line
Collagen supplements may offer modest benefits for weight loss, particularly when used as part of a structured dietary plan. The recent study suggests collagen-enriched protein bars may enhance satiety, preserve muscle mass, and support metabolic health. However, due to the small sample size, short study duration, and inclusion of other weight-loss-friendly ingredients, it remains uncertain whether collagen alone is responsible for the observed effects.
Larger, long-term studies are needed to verify these early findings and determine whether collagen can play a meaningful role in managing obesity. Until then, collagen supplements may be considered a low-risk addition to a healthy lifestyle, but they should not be relied on as a primary weight-loss tool.
For individuals exploring options for weight management, a comprehensive approach that includes nutrition, exercise, and professional guidance remains the most effective path forward.