Should you worry about heavy metals in protein powder?

September 12, 2026

Man holding supplement bottles in kitchen

Probably not, though it's worth a check. The 2024 and 2025 testing rounds found real lead and cadmium in some protein powders, plant-based ones ran higher than whey on average, and a share of products crossed a warning threshold. For a normal serving of whey on an ordinary diet, read the label instead of quitting protein.

That answer is boring on purpose. The headlines weren't. Two testing rounds landed within a year of each other, one from a testing nonprofit and one from Consumer Reports, and both put "heavy metals" next to "protein powder" in a way that reads like a warning label. The numbers underneath are narrower than the headlines, and more useful.

What did the 2024 and 2025 testing find?

The Clean Label Project tested 165 products from 70 brands using ICP-MS, the standard lab method for measuring trace metals, and reported that 47% exceeded at least one federal or state safety threshold, with 21% crossing twice the California Prop 65 level for lead [1]. Plant-based powders averaged about 5 times more cadmium than whey-based ones, and chocolate-flavored plant powders ran roughly 110 times higher than their vanilla versions [1]. Organic products averaged 3 times the lead of non-organic ones, a gap the report attributes mostly to organic lines skewing plant-based [1].

Consumer Reports ran its own test in late 2025: 23 popular protein powders and shakes, checked for lead. More than two-thirds exceeded CR's own daily intake benchmark, and a couple exceeded it by more than 10 times [2]. Plant-based powders averaged 9 times more lead than dairy-based ones and about twice as much as beef-based powders [2]. It had been 15 years since CR last ran this test, and the average came back higher this time, with fewer products at undetectable levels [2].

Two different organizations, two different labs. Same direction both times: plant-based protein carried more lead and cadmium than whey, on average. That's the finding worth taking away.

Where do the metals come from?

Most of this doesn't trace to a factory cutting corners. Contaminated added ingredients, such as colorants, fillers, or flavors, are a second and less common route [7], but the usual one is simpler than either. Lead, cadmium, and arsenic are naturally present in soil almost everywhere, and plants take up whatever is in the ground through their roots along with the nutrients they need [7]. A plant can't tell calcium from lead or zinc from cadmium at the point its roots absorb it. Milk comes from an animal's metabolism rather than straight from the ground, and both testing rounds found dairy-derived whey starting from a lower baseline, on average, than protein pulled straight from a plant [1][2].

Cacao is a well-studied example of just how much geography matters here. A synthesis of soil and plant data across cacao-growing regions found that the cadmium content of cocoa beans tracks the cadmium already in the soil they grew in, and that soil pH controls how available that cadmium is to the plant: acidic soil releases far more of it than neutral or alkaline soil does [6]. That's a property of the farm, not the factory. It's also the likeliest explanation for why the chocolate plant powders tested higher than the vanilla ones: cacao is the ingredient doing the absorbing, years before it reaches a protein blend [1][6].

None of this makes contamination a non-issue. It means the fix is choosing what a product is made from and where its inputs are grown, not accusing a specific brand of adding something to a tub. A single-ingredient product with one traceable input is easier to reason about than a formula built from several plant sources, each carrying its own soil history.

What does a Prop 65 warning mean?

California's Prop 65 sets a Maximum Allowable Dose Level, or MADL, for chemicals linked to reproductive harm. Lead's MADL is 0.5 micrograms a day. Cross that in a product sold in California and the label needs a warning [4]. That number sounds tiny on purpose. California's rule derives a MADL by finding the exposure level at which an assessment shows no observable reproductive effect, then dividing it by 1,000 [10]. The trigger sits a thousandfold below that no-effect level. It's a regulatory trigger built with a wide safety margin, not the dose at which harm has been shown to occur.

The FDA uses a different number for the same chemical. Its interim reference levels for lead are 2.2 micrograms a day for children and 8.8 micrograms a day for women of childbearing age [5], and they apply to total dietary exposure, everything a person eats in a day, not one product [3]. The FDA built in its own margin too: that level is "nearly ten times lower than the amount of lead intake from food that would be required to reach" the blood level where clinical follow-up is recommended [5]. It's also guidance, not an enforceable rule [5]. The average American adult is already exposed to up to 5.3 micrograms of lead a day through diet, per a 2019 analysis by FDA scientists, before protein powder enters the picture at all [3].

Put the two numbers side by side and the confusion makes sense: California's warning threshold (0.5 mcg/day) and the FDA's dietary guidance (8.8 mcg/day) are answering different questions, one narrow and one broad, and neither is "the" official safe number. A product carrying a Prop 65 warning has crossed a conservative state trigger. It has not necessarily crossed a line where harm is expected. Both things can be true at once.

How do you read a COA for heavy metals?

This is the part the hospital blogs and brand posts skip, and it's the skill worth having. A certificate of analysis for heavy metals should show four elements by name: arsenic, cadmium, lead, and mercury, each with its own result, not a single "heavy metals: pass" line lumping them together [8].

A few things to check before trusting the number:

The unit. Older tests report in parts per million (ppm); modern ones report in micrograms per gram, then convert to micrograms per day based on serving size, because the daily dose is what any safety threshold is measured against [8]. A result of 1 ppm lead in a 2-gram serving works out to 2 micrograms of lead in that serving, which is the number that actually matters, not the ppm figure alone [8].

What "not detected" means. "ND" is only as good as the method's detection limit. An older colorimetric test can call lead "not detected" at anything below 10 parts per million, while a material carrying 1.5 to 4 ppm, well above what a modern ICP-MS test would flag, would sail through that older method looking clean [8]. A COA that doesn't state its detection limit next to "ND" isn't telling you much.

The method and the lab. ICP-MS is the current standard. A lab accredited to ISO/IEC 17025 is being held to a documented quality standard for that result; one that isn't, isn't [8]. If a COA doesn't name a method, that's worth noticing on its own.

Which standard it's checked against. A result can be compliant against one legitimate standard and still look alarming next to another. USP's pharmacopeial exposure limit for lead is 5 micrograms a day, 10 times higher than California's Prop 65 trigger of 0.5 micrograms a day [4][9]. Both are real, defensible numbers. They're not the same question, so a COA that says "pass" is only useful once you know which line it passed.

What AUROM does about this

AUROM's creatine monohydrate is one ingredient, micronized creatine monohydrate, and a Certificate of Analysis is available per batch on request. It's a document, not a certification, and it's worth reading for exactly what it reports and nothing more. One ingredient means one thing to trace back to a source, not a blend of several inputs each with its own soil history.

The whey isolate follows the same principle on the label: whey protein isolate, natural flavors, stevia extract. Three ingredients, both flavors. Nothing to hide a fourth thing behind. AUROM doesn't currently sell a plant-based protein, so the category-wide finding above (plant sources running higher on average) isn't a claim about a competitor. It's just useful to know before you pick a protein source, whichever brand it comes from.

AUROM is made in a cGMP-compliant U.S. facility. That's one of exactly two claims AUROM makes about its manufacturing, the other being Made in the USA. Neither is a heavy-metals certification, and neither is presented as one.

Questions people ask

Does organic protein powder have less lead? No. In the Clean Label Project's testing, certified organic products averaged three times the lead of non-organic ones, mostly because organic lines skew toward plant-based protein, which tends to run higher regardless of the organic label [1]. Heavy-metals testing isn't part of what the USDA Organic seal actually checks [7].

Is chocolate protein worse than vanilla for heavy metals? For cadmium in plant-based powders, yes. It traces back to cacao being an unusually efficient absorber of cadmium from soil, a property of the plant and its growing region, not of any particular brand's process [1][6].

Does a Prop 65 warning mean a product is dangerous? It means the product crossed a state-set trigger built with a wide margin: the trigger sits at one-thousandth of the exposure level where an assessment found no observable reproductive effect [4][10]. It's a reason to look closer, not a diagnosis.

Should you avoid protein powder if you're pregnant? If you're pregnant, breastfeeding, or feeding a child, exposure guidance is more conservative and more individual than a blog post can responsibly cover. That's a conversation with your clinician, who can weigh it against your actual diet, not something to settle from an article.

How much lead is normal to get from food generally? Up to about 5.3 micrograms a day for the average American adult, per a 2019 analysis by FDA scientists, before protein powder is even in the picture, against an FDA total-diet guidance level of 8.8 micrograms a day for women of childbearing age [3][5]. Protein powder is one contributor among many, not the only one.

The one useful habit

You don't need to memorize a table of thresholds. You need one habit: before you buy, check whether the brand publishes a heavy-metals COA at all, and if it does, check that it names all four metals separately, states its method and detection limit, and tells you which standard it's measured against. A brand that shows you that document isn't asking you to trust a badge. It's showing you the actual number.

For more on reading the rest of a COA, not just the heavy-metals line, see what a certificate of analysis actually says. For the broader skill of reading a label end to end, see how to read a supplement label, line by line. And for what radical transparency looks like as a policy rather than a slogan, see how AUROM handles it.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.