Does collagen actually work?
Collagen supplements are everywhere. Unlike most wellness trends, there’s real evidence behind them — one trial found collagen peptides improved wrinkles, elasticity and hydration over 12 weeks with no side effects. So the real question isn’t whether collagen works. It’s whether the tub you’re taking every day is clean.
Why purity is worth checking
Supplements aren’t tested for safety before sale the way medicines are. There’s no routine check that a batch is free of contaminants — it depends on whether the manufacturer tests and publishes results. Collagen is made from fish or cattle. Fish-based (marine) collagen can carry small traces of arsenic from the sea. That’s why testing — and what kind of testing — matters.
What independent testing found
Independent lab testing of two collagen products found a real difference in arsenic. The other heavy metals were below detectable levels in both:
| Heavy metal | Product A | Product B |
|---|---|---|
| Arsenic | 0.09 ppm | 0.44 ppm |
| Lead | <0.010 ppm | <0.010 ppm |
| Cadmium | <0.005 ppm | <0.005 ppm |
| Mercury | <0.005 ppm | <0.005 ppm |
What that number actually means
0.44 ppm is roughly five times higher than the other sample. But it’s still within the current EU limit for total arsenic in collagen (up to 1 ppm). It doesn’t break any rule. The fair conclusion: this is higher than the other sample, still within legal limits, and a good reason to ask the brand a sharper question — not proof the product is dangerous.
The detail most labels skip: two types of arsenic
Arsenic comes in two forms. Inorganic arsenic is the genuinely harmful, cancer-linked kind. Organic arsenic — common in seafood — is considered far less of a concern. A “total arsenic” test can’t tell you which one you’re getting. The test that matters measures inorganic arsenic specifically. It costs more, which is why many brands skip it.
Why small amounts still matter
Arsenic builds up in the body over time. Even within legal limits, a daily supplement is an extra, ongoing exposure on top of your normal diet. Some people already have a higher background level from rice-heavy diets, seafood, or well water. This isn’t a reason to panic about one product. It’s a reason to check anything you take every day, indefinitely.
How to check a collagen supplement
- Ask for a Certificate of Analysis for the exact batch you’re buying.
- Ask specifically about inorganic arsenic — not just “heavy-metal tested.”
- Prefer independent, third-party testing over the brand’s own claims.
- Marine collagen carries more risk of background arsenic than bovine — ask more questions there.
The bottom line
Collagen has real evidence behind it. The question isn’t whether it works — it’s what else is in the tub. Ask for total and inorganic arsenic figures. A brand that tests properly and shows the results is more trustworthy than one relying on a reassuring label.
Sources
- Kim J, et al. Oral Supplementation of Low-Molecular-Weight Collagen Peptides Reduces Skin Wrinkles. J Med Food. 2022;25(12):1146–1154. DOI
- Ganie SY, et al. Arsenic toxicity: sources, pathophysiology and mechanism. Toxicol Res (Camb). 2023;13(1):tfad111. DOI
- Luvonga C, et al. Organoarsenicals in Seafood: Occurrence, Dietary Exposure, Toxicity and Risk Assessment. J Agric Food Chem. 2020;68(4):943–960. DOI
General information only, not medical advice. Test figures are from independent sampling of two unnamed products, not any brand’s typical output; both fell within current total-arsenic limits. Discuss supplements with a qualified practitioner if pregnant, breastfeeding or managing a health condition.
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