You can do everything right — clean ingredients, solid testing, accurate labels — and still get hit with a Prop 65 problem the moment you sell into California. The state’s warning law is one of the most litigated consumer regulations in the country, and supplements are a frequent target. For a brand owner, Prop 65 isn’t a California technicality; it’s a national risk, because California is too big a market to avoid.
Here’s how to understand Prop 65 and avoid the warning trap.
Proposition 65 is a California law that requires businesses to provide a “clear and reasonable” warning before exposing people to chemicals the state lists as causing cancer or reproductive harm. The list includes substances relevant to supplements — notably heavy metals like lead and cadmium. If your product can expose a consumer above the state’s threshold, it may require a warning.
Prop 65’s exposure thresholds for some chemicals are extremely low — far stricter than typical federal limits. Because heavy metals occur naturally in botanicals, greens, and minerals, a supplement that passes a standard internal limit can still exceed a Prop 65 threshold. That gap is where brands get blindsided: compliant by one standard, exposed by another.
Prop 65 is enforced not only by the state but by private litigants, who actively test products on the shelf and issue notices of violation. A single notice can mean legal costs and a settlement, regardless of whether your product is genuinely unsafe. This private-enforcement engine is why Prop 65 generates so many supplement actions — and why prevention beats reaction.
| Action | Why It Protects You |
|---|---|
| Test to Prop 65 levels | Confirm exposures against California thresholds, not just federal limits |
| Scrutinize high-risk ingredients | Botanicals, greens, cacao, and minerals are common sources |
| Calculate exposure per serving | The warning is based on consumer exposure at the labeled dose |
| Decide on warnings deliberately | Warn when required; don’t slap warnings on reflexively |
Some brands over-warn — adding a Prop 65 label “just in case” — which can scare consumers and signal a problem that may not exist. Others under-warn and get sued. The right approach is data-driven: test your finished product, calculate exposure at the serving size, and apply a warning only where the numbers require it. That decision should be based on your actual results, ideally with regulatory guidance.
Staying ahead of Prop 65 starts with testing and sourcing — which is your manufacturer’s domain. A partner who tests finished products to strict heavy-metal levels, sources low-contaminant raw materials, and provides the data lets you make the warning decision from facts instead of fear. Confirm your manufacturer can test to California-relevant thresholds before you ship there.
Proposition 65 is a California law requiring warnings before exposing consumers to listed chemicals that cause cancer or reproductive harm. It applies to supplements because the list includes heavy metals that naturally occur in many ingredients.
Because Prop 65’s thresholds for some chemicals are far lower than typical federal limits. A product compliant with standard heavy-metal limits can still exceed California’s stricter exposure levels, especially with botanical or mineral ingredients.
Not reflexively. Over-warning can deter consumers and imply a problem that may not exist. The better approach is to test your finished product, calculate exposure at the serving size, and apply a warning only where the data requires it.
Selling into California? UniWell Labs tests finished products to strict heavy-metal levels and provides the data brand owners need to make the Prop 65 call from facts. Talk to our team about compliance.