Experts say most adults don't need protein powders daily and can safely meet protein needs through a balanced diet.
Concerning levels of lead and other toxic heavy metals were detected in popular protein powders and shakes, according to a new Consumer Reports investigation.
Although no safe level of lead has been identified, over time, lead exposure can cause nausea, high blood pressure, depression, or fertility issues.
According to Consumer Reports, about 70% of the protein powder samples had over 120% of California Prop 65's maximum allowable dose level for lead, which is 0.5 micograms per day.
The researchers specifically recommend avoiding two tested products: Naked Nutrition's Vegan Mass Gainer powder, which had 1,572% of the level of concern for lead; and Huel's Black Edition powder, which had 1,288% per serving. Some products with lower lead levels, like MuscleMeds Carnivor Mass and Vega Premium Sport Plant-Based Protein, are ok to eat "occasionally" at no more than 2.75 servings per week and 3.75 servings per week, respectively.
"Because this is a product that's not an occasional treat -- people have it daily or sometimes even multiple times a day -- they should be aware that they could be getting a significant amount of lead from consuming these types of products," Sana Mujahid, PhD, manager of food safety research and testing at Consumer Reports, told Verywell.
However, people should not panic after seeing the results, she added.
The 0.5 microgram per day target is far lower than the Food and Drug Administration (FDA)'s guidance that adults keep daily limits under 8.8 micrograms. Although California's law has a "wide safety margin," the Consumer Reports team decided to use this limit because the researchers felt it was the "most health-protective limit out there," Mujahid said.
The investigation found that plant-based protein supplements contained higher lead levels than dairy and animal-based products.
Recent reports from the nonprofit Clean Label Project have also found that plant-based protein powders generally contain higher amounts of lead than whey-based products.
Crops can absorb heavy metals, such as lead, arsenic, and cadmium, from the soil. Growing conditions and manufacturing processes may explain why plant-based products had higher lead levels, Mujahid said.
"There's more need for testing raw ingredients and testing of the final product. Our results show that some companies are doing better than others," she added.
Lead exposure is especially dangerous for children and pregnant people since this heavy metal can cause harm during growth and development. However, most healthy adults don't need to avoid protein powders entirely.
Although the new report found that multiple protein powders contained elevated lead levels compared to the reference standard, that doesn't mean protein powders cause lead poisoning or pose a clear health risk, according to Kelly Krisna Johnson-Arbor, MD, a medical toxicologist at MedStar Georgetown University Hospital.
Many adults actually don't need protein supplements at all, despite their popularity. "Although occasional protein powder consumption is most likely safe for most of us, I think it's important to realize that we can get protein from other sources," Johnson-Arbor told Verywell.
While individual protein needs vary, most adults should consume about 0.8 and 1.6 grams of protein per kilogram of their body weight. That means someone who weighs 150 pounds needs at least 55 grams of protein per day.
"If you eat a healthy, well-balanced diet that includes fresh fruits and vegetables and other sources of protein -- meats, beans, nuts, dairy products -- you're most likely going to get the protein you need for your dietary requirements," Johnson-Arbor added.