Prop 65
California Proposition 65 (Prop 65) requires businesses to warn consumers about products that may expose them to chemicals known to the state of California to cause cancer or reproductive harm. Many protein powders carry Prop 65 warnings due to trace lead or cadmium content.
Why It Matters
Prop 65 limits are extremely conservative, often set at 1/1000 of the level at which no harm has been observed in animal studies. Many foods, including organic vegetables, exceed Prop 65 thresholds. A Prop 65 warning on a protein tub does not necessarily mean it is unsafe; it means the brand has chosen to disclose rather than risk a lawsuit.
That said, a warning is still useful information. Brands that publish per-batch heavy metals testing below Prop 65 limits are demonstrating both transparency and lower contamination than the legal floor.
How to Spot It on a Label
Look for the WARNING: This product can expose you to chemicals... block on the back panel or side of the tub. Some brands instead state tested below Prop 65 limits on the front; check their published lab data to verify the claim.
Examples from real products
Related Terms
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