Heavy Metals in Collagen: What the Testing Found
Collagen got its own heavy-metal report five years before protein powder’s big one made the news. In 2020 the Clean Label Project, working with the Organic Consumers Association, bought 30 collagen products on Amazon and sent them to two independent labs to test for lead, cadmium, arsenic and mercury.
Lead turned up in 37% of them.
Short answer: Some collagen powders carry detectable heavy metals, and the range between products is wide. In that 2020 test, one unflavored powder came in at more than three times California’s Proposition 65 lead threshold and three chocolate products were over twice it. Prop 65 is a warning-label threshold rather than a safety line, so the useful part is the gap between brands, which is exactly why published batch testing is worth paying for.
What the 2020 collagen test found
The labs were HRI Labs and Ellipse Analytics, running ICP-MS (the standard method for trace metals) down to eight parts per billion. The white paper names names.
The highest lead result was Orgain Collagen Peptides, unflavored, at more than three times the Prop 65 threshold. Three chocolate products each came in above twice it: Ancient Nutrition Keto Collagen, Bulletproof Collagen Protein and Preferred Elements Keto Collagen. Cadmium showed up in 17% of the products, with Bulletproof’s chocolate over twice its threshold.
Arsenic was the most common find, in 64% of products, but none went over the limit. Mercury showed up in about a third, at trace levels only. The three cleanest products in the round were BioOptimal, NeoCell Super Collagen and Puori CP1.
A fair warning about using this list to shop today. It’s one round of testing on products bought in 2020, and suppliers and formulas change, so treat it as a snapshot of the category rather than a current verdict on any brand. The industry also called the report sensationalized at the time.
Chocolate loses again
If you read our write-up on heavy metals in protein powder, this part will sound familiar. Of the four lead results the report singles out as more than double the threshold, three were chocolate, and the worst cadmium result was chocolate too.
The reason isn’t the collagen. Cacao plants pull cadmium out of the soil readily, so cocoa powder brings its own metals into whatever it’s mixed with. An unflavored tub removes that variable completely, and it’s cheaper.
The one catch is that the single highest lead result in 2020 was an unflavored powder. Unflavored stacks the odds in your favor. It doesn’t guarantee anything by itself.
Bone, hide or fish: does the source matter?
Here’s where it gets interesting. About 94% of the lead stored in an adult body sits in bone, according to the CDC’s toxic substances agency, and it’s released back into the blood during pregnancy, breastfeeding, menopause and aging. Animals store it the same way. So anything made from bone has a plausible route to carrying lead.
That’s the idea behind a much-shared 2013 bone broth study. It measured 9.5 micrograms of lead per liter in chicken broth made with skin and cartilage and 7.01 in a bone broth, against 0.89 in the tap water used to make them. It was tiny, though, and a critique from the Weston A. Price Foundation (hardly a neutral party on bone broth) pointed out it gave no sourcing or cookware details and that every result sat under the EPA’s 15 µg/L action level for tap water. A 2025 ConsumerLab test of 10 bone broths found none with concerning lead, arsenic, cadmium or mercury.
Marine collagen has one recent peer-reviewed look. A 2025 study in Open Medicine tested collagen from fish and jellyfish and found arsenic averaging 0.59 mg/kg and lead 0.13 mg/kg, with mercury detectable in only 12% of samples and nothing over EU limits. We couldn’t find a comparable peer-reviewed dataset for collagen made from cattle hides, which is where most bovine peptides come from. There’s more on the source question in marine vs bovine collagen.
The warnings and the settlements
California’s Prop 65 system is the other place metals in collagen show up, and it’s public.
In 2017, a 60-day notice alleged lead and cadmium in Vital Proteins products. The case settled for $92,500, with warnings required from August 2018 on products delivering more than 0.5 micrograms of lead or 4.1 micrograms of cadmium a day. The Collagen Co.’s Glow Shakes settled a lead notice in May 2026 for $21,000 plus warnings. And in June 2026 a group called Public Protection Alliance filed lead notices against a marine collagen and two more supplement products, all sold on Amazon.
A 60-day notice is an allegation, not a lab finding the state has confirmed. A settlement with a warning requirement tells you more.
Prop 65, USP or FDA: which limit counts
This one is a little tricky, because the three limits you’ll see quoted aren’t measuring the same thing.
| Limit | Lead allowed | Who it applies to |
|---|---|---|
| California Prop 65 (MADL) | 0.5 micrograms a day | A warning-label trigger for products sold in California, set in 1989 |
| USP chapter 2232 | 5 micrograms a day | Only supplements labeled as meeting USP standards |
| FDA Closer to Zero | Set per food type | Foods for babies and young children, not supplements |
So the Prop 65 line is ten times stricter than the USP one, and both are voluntary for most collagen tubs in the sense that nobody tests your powder against either before it ships. The Prop 65 lead figure is deliberately conservative. The USP limits are an industry quality standard. And the FDA’s Closer to Zero program doesn’t mention supplements at all.
What makes collagen worth this much attention is the habit rather than any single scoop. Lead matters mostly through cumulative exposure, and collagen is sold as something you take every day, for months or years.
How I’d shop around it
Start with unflavored. It’s the cheapest change and it takes cacao’s cadmium off the table.
Then look for a brand that publishes batch results for heavy metals, not one that just says it tests. The difference between a certificate of analysis you can read and a sentence on a website is the whole point, and what “third-party tested” really means walks through which named programs actually check. If you’re buying online, a Prop 65 warning on the product page is a small but real signal too.
The brands in our clean collagen picks were chosen with this in mind. And before you spend anything, it’s worth reading what the evidence says collagen actually does, because a clean tub of something that doesn’t work for you still isn’t a bargain.
Frequently asked questions
Does collagen powder contain lead?
Some does. In a 2020 test of 30 collagen products, lead was detected in 37%, with one unflavored powder at more than three times California’s Prop 65 threshold and three chocolate products over twice it. Others tested clean, so the brand you pick changes a lot.
Is marine collagen lower in heavy metals than bovine?
There isn’t enough data to say. A 2025 study of fish and jellyfish collagen found low arsenic and lead and nothing over EU limits, but we couldn’t find an equivalent peer-reviewed dataset for bovine hide collagen to compare it against. Published batch testing from the specific brand tells you more than the source animal does.
Is bone broth high in lead?
Probably not at worrying levels. A small 2013 study found more lead in chicken bone broth than in tap water, but every result sat below the EPA’s action level for drinking water, and a 2025 ConsumerLab test of 10 bone broths found none with concerning heavy-metal levels.
Which collagen has the least heavy metals?
In the 2020 Clean Label Project round, the cleanest were BioOptimal, NeoCell Super Collagen and Puori CP1. That’s a single round of testing from five years ago, so for a current answer, choose an unflavored powder from a brand that publishes heavy-metal results for each batch.
What does a Prop 65 warning on collagen mean?
It means the product may deliver more of a listed chemical than California’s threshold, which for lead is 0.5 micrograms a day. That threshold is set well below federal levels on purpose, so a warning isn’t proof of harm. It is a useful comparison between two otherwise similar tubs.
Related reading
The rest of this series: does collagen actually work, marine vs bovine collagen, and which grass-fed and wild-caught claims are verified. For vetted picks, see the best clean collagen supplements. The same testing story played out in protein powder, and our guide to the red flags in the supplement industry covers the wider category.
Sources: Clean Label Project and Organic Consumers Association, collagen white paper, 2020. Monro, Leon & Puri, Medical Hypotheses, 2013. Cammilleri et al., Open Medicine, 2025. ATSDR, lead toxicity: biologic fate. California Office of the Attorney General, Prop 65 notices 2017-02480 and 2026-00831. ConsumerLab, bone broth tests, 2025.
