A recent Consumer Reports investigation involving 23 protein powders and ready-to-drink shakes found that more than two-thirds of the tested products contained unsafe lead levels in a single serving, according to the brand's own food safety experts. Some powders even had more than 10 times the amount of lead considered safe for daily intake by these same experts.
Another report conducted from 2024 to 2025 by the nonprofit organization Clean Project Label determined that out of 160 protein powders that were tested, 7% exceeded California Proposition 65 safety thresholds for toxic metals. When compared to whey-based protein powders, plant-based powders had three times the amount of lead, and chocolate powders had four times more lead than vanilla. Even more surprising, organic protein powders had three times more lead and twice as much cadmium, another metal, as those that were non-organic.
While these numbers may seem concerning when you're trying to reach your protein goals, there is additional context you should be aware of regarding protein powders and heavy metals. To break it down, we consulted with dietitians to determine what constitutes a "safe protein powder."
The report on heavy metals in protein powders
Knowing which studies and reports to trust can be tricky. According to sports dietitian Kelly Jones, the Clean Project Label study was an independent report not published in a peer-reviewed journal and did not go through the institutional review board approval process. “Since Clean Label Project did not disclose any of the protein powders tested but recommends only brands that pay for their independent certification, I do not recommend my clients, audience or consumers as a whole worry about this study,” she said.
Clara Nosek, a registered dietitian, points out that the Clean Label Project did not disclose its methodology or a hazard quotient, which tells you how much of the contaminant was used to assess the potential health risks associated with its exposure. “The lack of methodology means their findings cannot be reproduced, which does send up red flags from a scientific methods perspective,” Nosek warns.
You’ve probably heard the term “the dose makes the poison,” which means that to deem an ingredient harmful, there needs to be a specific dose mentioned as well. Keep in mind that too much of anything, even water, can be bad for you. It’s important to understand that detection of an ingredient does not equal immediate health risk.
“Just because a chemical is present, doesn’t mean it’s harmful in the amount present,” explains Nosek, adding that the study does not “explicitly state whether or not the concentration of heavy metals found in the powders posed any direct health risks -- which means it’s clearly an emotional manipulation.”
A solid study should be transparent in its methodology so others understand the scientific method and data the author used to reach their conclusions. Additionally, a study should be peer-reviewed, meaning experts in the field have evaluated its findings, research methods, citations and contribution to existing knowledge on the topic. This is a rigorous process since they must critically review each piece of information before validating it. The author also remains anonymous to minimize any potential bias during the evaluation. If it passes the peer review process, it’s then published in a scholarly journal.
If you want to know if a study should or shouldn’t be trusted, Nosek advises looking out for these red flags:
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