Nutrition industry leaders challenge Clean Label Project’s contaminated protein powder claims
Research by the Clean Label Project (CLP) reveals that 47% of tested protein powders exceeded at least one federal or state regulatory set threshold for heavy metal contamination such as lead and cadmium. However, US industry associations, the Natural Products Association and the Council for Responsible Nutrition (CRN), call the report’s methodology and outcomes into question.
Both organizations say the CLP denied their requests to disclose the methodology and the data behind the allegations.
“CRN supports efforts to ensure the safety and quality of dietary supplements, including protein powders. However, as we have noted in the past, reports like those issued by the Clean Label Project often lack critical context and risk misleading consumers rather than empowering them,” says Andrea Wong, Ph.D., SVP of Scientific & Regulatory Affairs at CRN.
Daniel Fabricant, Ph.D., president and CEO of the NPA, says that CLP published a similar report attacking collagen supplements, “but this so-called study is nothing but hot air.”
“When we asked them to disclose its funders and the full methodology of the collagen study, they did not respond and instead hid from the truth. Again, we demand that they disclose this so-called study’s methodology instead of peddling misinformation and profiting from referred products to online retailers listed on its website.”
Protein powder contamination
With the study, CLP aims to enable consumers to make informed choices, prioritizing safety and quality in their supplements. The organization tested 160 products from 70 top-selling brands, representing 83% of the US market.
The report benchmarks these products against California Proposition 65 safety thresholds. This proposition protects the state’s drinking water from contamination with chemicals known to cause cancer, congenital disabilities or other reproductive harm. It also requires businesses to inform citizens about exposure to these chemicals.
In its report, CLP says that 47% of products tested exceeded California Proposition 65 safety thresholds for toxic metals. In addition, organic products showed higher levels of contamination — three times more lead and twice the amount of cadmium than non-organic protein powders.
Meanwhile, plant-based protein powders showed three times more lead than whey-based alternatives. Also, chocolate-flavored powders contained four times more lead than vanilla.
CRN’s Wong highlights that detecting contaminants “does not inherently equate to a health risk.”
“Modern analytical techniques can detect even trace levels of naturally occurring elements, such as heavy metals, present in soil, air and water. These trace levels are often well below established safety thresholds set by federal agencies like the FDA and the Environmental Protection Agency (EPA).”
NPA and CRN request CLP to share the methodology and data for its allegations so they can be verified.Unaligned with federal guidelines
Wong also stresses that California Proposition 65 imposes “uniquely stringent” limits that do not align with federal guidelines.
“For example, it imposes a 1,000-fold safety factor below the level at which no harmful effects have been observed, and it requires labeling of products over that amount, not a ban on them.”
“While CLP’s intentions to protect consumers are commendable, the lack of harmonization with FDA or EPA standards can result in unnecessary consumer alarm,” she cautions.
“CRN has consistently advocated for science-based federal standards that balance consumer safety with practicality and consistency across all states. Federal agencies regulate the manufacturing of food and dietary supplements, including testing and monitoring protocols for heavy metals.”
To ensure safety and transparency, Wong highlights the importance of encouraging a unified regulatory approach that upholds reasonable, evidence-based standards.
“Aligning state initiatives like Proposition 65 with federal guidelines would reduce confusion for consumers and manufacturers while maintaining public safety. CRN and its members remain committed to collaborating with stakeholders to promote rigorous, transparent and uniform safety standards across the dietary supplement industry.”
Methodology under scrutiny
CLP’s report notes that it purchased and rigorously tested 160 top-selling protein powders sourced from Nielsen and Amazon’s best-seller lists. The researchers supplemented these with top products from natural and organic marketplaces.
The organization collaborated with Ellipse Analytics, an analytical chemistry lab, to test industrial chemical panels, including heavy metals and bisphenols. In total, 258 different chemicals and heavy metals were tested, resulting in 35,862 data points from all samples to benchmark its findings.
However, NPA and CRN stress that the report needs verification and request that the CLP share its methodology and data.
Wong says: “CLP has not provided sufficient transparency regarding how products were selected, the criteria for contamination thresholds or the interpretive framework for their findings.”
“Without such clarity, consumers and industry stakeholders cannot fully evaluate the validity of the claims. CRN urges CLP to publish its findings in peer-reviewed journals and provide recommendations grounded in scientific evidence.”
In other consumer safety news, CRN and the US Pharmacopoeia recently expressed grave concerns over the accuracy of research findings that some prenatal vitamins contain high levels of toxic metals. The organizations flagged that the study was inaccurate and had a flawed methodology, as the limits and units were incorrectly applied, and the values presented were incorrect.
