Can Collagen Supplements Cause Weight Gain?
Last updated: August 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy
Not directly. Collagen supplies about 35–40 calories per 10 g, which is negligible unless you are adding it to something already calorific. Weight gain attributed to collagen usually comes from what it is mixed into, or from the flavoured and sweetened versions.
Key takeaways
- About 35–40 kcal per 10 g — too little to drive weight gain.
- Protein is generally satiating rather than fattening.
- Check flavoured and 'creamer' versions for added sugars and fats.
The calorie arithmetic
Collagen is protein at roughly 4 calories per gram, so a 10 g serving is about 40 calories. Adding 40 calories daily to an otherwise unchanged diet would produce a very small change over a long period. It is not a plausible cause of noticeable weight gain.
Where the calories actually come from
Flavoured collagen products, collagen creamers and collagen coffee blends often contain added sugars, fats or medium-chain triglycerides that take a serving well above 40 calories. If you mix unflavoured collagen into a smoothie with juice, banana and nut butter, the collagen is not the variable that changed.
The water point
Collagen supports skin hydration, and some people notice the scale move slightly in the first weeks. Any such change is water, not fat, and it is small. Protein in general increases satiety, which is why higher-protein diets tend to help rather than hinder weight management.
Key ingredients to understand
The ingredients most relevant to this question, with what the evidence actually supports:
- Collagen Peptides — Hydrolysed collagen peptides have some of the better evidence in the supplement market for skin hydration and elasticity, and moderate evidence…
- Whey Protein — Whey is a complete, rapidly absorbed protein high in leucine, and it has as strong an evidence base for muscle protein synthesis as anything in…
- Marine Collagen — Marine collagen comes from fish skin and scales, is predominantly type I — the type that dominates skin — and has smaller peptides that may…
- Collagen (Hydrolysed Peptides) — Collagen peptides are the most popular skin and joint supplement. There is some genuine trial evidence for modest improvements in skin hydration…
Frequently asked questions
Should I count it in my calories?
Yes, count 40 calories per 10 g. Just do not expect it to matter much.
Does it affect blood sugar?
Unflavoured collagen has negligible carbohydrate. Flavoured versions may not.
Can it help with weight loss?
Only through satiety, and other proteins do that at least as well.
Related on FactoWiki
- All health answers
- Ingredient evidence guides
- Collagen Peptides — ingredient guide
- Whey Protein — ingredient guide
- How we review
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