Recent investigations by Consumer Reports into the contents of popular protein supplements have raised potential concerns. A Consumer Reports study examining 23 protein powders and shakes indicated that, according to the brand's own safety experts, over two-thirds contained lead levels deemed unsafe in a single serving, with some exceeding recommended daily limits significantly.
Furthermore, a report conducted from 2024 to 2025 by the Clean Project Label from 2024-2025 tested 160 protein powders, finding that 7% surpassed California Proposition 65 thresholds for toxic metals. This report highlighted that plant-based powders contained three times more lead than whey-based protein powders, chocolate powders had four times more lead than vanilla, and organic powders surprisingly contained higher levels of lead and cadmium compared to non-organic versions.
While these figures might cause concern for individuals using these products to supplement their protein intake, it's important to consider the full context surrounding heavy metals in protein powders. To provide clarity, we consulted with dietitians to understand the potential risks and help define 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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