The global market for protein supplements is massive. According to Future Market Insights, it was valued at nearly $27 billion in 2024, and by 2034, it could exceed $55.8 billion. “Protein powders are becoming an essential supplement for athletes, bodybuilders, and fitness-conscious consumers,” the market research platform notes. After all, protein is essential for building muscle. However, recent research suggests that the protein market is far from perfect. Some protein powders, specifically, might be putting our health at risk from toxic metals.
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A new study conducted by the Clean Label Project analyzed 160 protein products from 70 brands, and concluded that certain protein powders contain heavy metals in amounts that exceed those specified by California Proposition 65. The law, which has been in force since the 1980s, requires businesses to provide warnings about chemicals in their products that could cause harm.
Is it dangerous to consume protein powders with heavy metals?
According to the new study, some rice, pea, and soy protein powders contained five times more cadmium than whey protein powders. Chocolate protein powders contained 110 times more cadmium than vanilla-based options. Cadmium is a natural metal, but when consumed in excess by humans, it can be dangerous.
“Cadmium is a carcinogen and is linked to serious kidney and bone damage,” explains Jennifer Scherer, BS, ACE-CPT, MES, RDN, dietitian, medical exercise specialist, and founder of Fredericksburg Fitness Studio, to VegNews. “Long-term exposure can lead to renal dysfunction (kidney failure), as it is primarily stored in the kidneys. Cadmium also interferes with calcium metabolism, contributing to osteoporosis and bone fractures.”
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Scherer added that The World Health Organization (WHO) classifies cadmium as a Group 1 carcinogen, which means there is strong evidence linking it to cancer.
Cadmium wasn’t the only metal that researchers were concerned about. Their findings also noted that chocolate protein powders contained four times more lead—another natural metal—than vanilla-flavored options.
“Chronic exposure to lead can cause a range of health issues, particularly neurological problems,” adds Scherer. “In adults, it can lead to high blood pressure, kidney damage, and impaired cognitive function. In children, lead exposure is more dangerous, potentially causing developmental delays, lower IQ, and learning disabilities. There is also evidence linking lead exposure to reproductive toxicity in both men and women.”
3 ways to boost your protein intake safely, according to a dietitian
The findings are concerning. And they’re not alone—whey protein has also been linked with harmful ingredients (read more on that here). So what do you do if you want to keep building muscle with the help of protein supplements like protein powder? Good news: There are many ways to increase your protein intake safely. Scherer gave us three top tips; find them listed below.
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1 Look for reliable certifications
There are a few certifications you need to know about if you’re looking for a safe protein powder with low levels of toxic metals. The first is NSF Certified for Sport, says Scherer. “It’s a reliable certification, particularly for athletes,” she explained. “It ensures that the product has been tested for banned substances and contaminants, including heavy metals like lead, cadmium, and arsenic.”
Scherer added that the USDA Organic certification is worth looking out for, too, although it won’t guarantee that the protein powder is heavy metal-free. “Organic farming practices generally result in lower levels of heavy metals due to more stringent soil management and farming techniques,” she said. Other helpful certifications to look out for are US Pharmacopeia (“a respected independent organization that evaluates supplement quality, with a focus on purity and potency”) and Informed Choice, which carries out rigorous testing on products to ensure they’re free of banned substances.
On top of this, some brands provide their own information on their sourcing and heavy metal content. “Always ask for this if it isn’t available on the product page,” advises Scherer. She recommended a few brands that have robust certifications, including Klean Athlete, Juice Plus, Orgain, and Ghost Protein—all of which offer plant-based options.
“Protein powders can be an excellent way to boost protein intake, especially for athletes or those with specific dietary needs, but it’s essential to do thorough research to ensure you’re choosing a safe and high-quality product. Look for third-party certifications like NSF Certified for Sport or USDA Organic to help guide your choices, and always check for transparency on testing for heavy metals,” Scherer said.
2 Choose hemp protein over rice
According to Scherer, hemp protein powders tend to have lower levels of heavy metals. This is because hemp is typically grown in conditions that do not require heavy use of pesticides or synthetic fertilizers, which can contribute to heavy metal contamination. “Hemp plants can even help detoxify soils contaminated with metals, making them a relatively clean source of protein,” she explained. “Hemp protein is particularly beneficial for people seeking a low-toxicity alternative to rice-based proteins.”
Rice protein, on the other hand, tends to be higher in contaminants, and this is because of the way it is cultivated. “Rice plants are particularly prone to absorbing from contaminated soil or irrigation water,” says Scherer.
While the Clean Label Project study warned about pea protein, other studies have suggested that it is lower in contaminants than other protein powders, especially when it’s organic. One 2021 study, for example, suggested that organic pea protein had lower levels of lead, cadmium, and arsenic than conventional pea protein.
“Studies have shown that pea plants absorb fewer heavy metals compared to rice plants, making pea protein a safer alternative,” says Scherer. “Peas tend to accumulate fewer cadmium and lead levels than rice and are grown in soils that are less likely to have high heavy metal concentrations.”
“When in doubt, consulting a registered dietitian is a smart way to ensure you’re meeting your nutritional needs safely. With the right approach, you can safely meet your protein goals while avoiding unnecessary risks,” Scherer advised.
3 Choose protein-rich whole foods instead
If you want to skip protein powder, you do have another option available when it comes to boosting protein intake: food. “Whole food alternatives to protein powders can offer a range of nutrients and protein without the risk of heavy metal exposure,” said Scherer. Of course, many animal products are a source of protein, but many plant-based ingredients are too. Scherer pointed to plant-based whole foods like tofu, tempeh, nuts, seeds, and legumes, for example. Find more protein-packed plant-based foods here.
“If heavy metal exposure is a major concern, whole food sources can provide ample protein without the added risks,” adds Scherer. “A balanced diet rich in these whole foods can offer additional nutrients that protein powders can’t match.”
For more plant-based stories like this, read:
Charlotte is a VegNews editor and writer based in sunny Southsea on England’s southern coast.
