Prop 65: The Good, The Bad, The Ugly

If you’ve ever seen a warning label on a supplement bottle mentioning California and cancer, you’ve met Proposition 65 — and you’ve probably had a moment of “wait, what?” Just know that reaction is totally fair. The label is alarming by design and confusing by accident. Here’s what the law actually does, where it falls short, and how we think about it.

What Prop 65 Actually Is

Proposition 65 — officially the Safe Drinking Water and Toxic Enforcement Act of 1986 — is a California right-to-know law, not a product ban. It requires businesses to warn consumers when a product may expose them to any of the hundreds of chemicals on California’s list of substances linked to cancer or reproductive harm, at levels above a state-set threshold. It doesn’t evaluate whether a product is safe to sell. It only determines whether a warning is legally required.

For supplements specifically, this usually comes down to trace heavy metals — lead, cadmium, arsenic, mercury — that occur naturally in soil, water, and the plants or marine life grown or caught in them. Prop 65’s purpose is disclosure, not restriction: the state publishes the list, sets the thresholds, and lets consumers decide what to do with the information.

The Good

The thresholds behind Prop 65 are, by design, extremely conservative. The “safe harbor level” is set well below the level where regulators believe meaningful risk begins, often by a wide margin. That’s a deliberate choice: California would rather warn early and often than risk under-warning.

The practical upside is that a Prop 65 warning is frequently a byproduct of testing rigorously enough to find something, not evidence of a poorly made product. Third-party lab testing is what turns up trace-level findings in the first place — a brand that never tests won’t trigger the label, and a brand that tests at the ingredient and finished-product level is more likely to.

More good news: we third-party test all of our products as a part of our Supplement Quality Standard — a standard that should be implemented across the supplement space. 

The Bad

The language itself is where things get genuinely confusing. Prop 65 warnings historically didn’t require companies to name the specific chemical responsible, which left consumers staring at a scary sentence with no way to know whether it referred to a trace mineral naturally present in a plant-based ingredient or something else entirely. Newer requirements have started to close that gap, but the core wording — “known to the State of California to cause cancer, birth defects, or other reproductive harm” — remains dramatic regardless of the actual exposure level behind it.

This creates a mismatch: a warning built for legal disclosure purposes reads, to most people, like a safety verdict. It isn’t one. The label alone doesn’t tell you how much you should worry — it tells you a threshold, set by California, was crossed.

The Ugly

The part that draws the most legitimate criticism is enforcement. Prop 65 is largely enforced through private lawsuits rather than direct agency review — a business can be sued by private parties “acting in the public interest,” which has created financial incentive for litigation independent of actual public health outcomes. It also applies more stringently to formulated products than to whole foods: a supplement made from an ingredient can require a warning at trace levels that the same ingredient, eaten on its own, would not.

That inconsistency is a fair critique of how the law is structured, but it doesn’t change what a warning does and doesn’t tell you about a given product’s testing rigor.

Where This Leaves You as a Shopper

A Prop 65 warning isn’t a shortcut for “avoid this” or “trust this” — it’s a regulatory disclosure with a specific, narrow legal meaning. The more useful question isn’t whether a label carries the warning. It’s whether the company behind it actually tests for what the warning is about, discloses what it finds, and holds itself to that standard regardless of what California requires.

That’s the standard we hold ourselves to under the Compliance layer of the Supplement Quality Standard — third-party testing, transparent labeling, and manufacturing that meets cGMP requirements, independent of whether any single product happens to trigger a Prop 65 warning in a given state. Rigorous testing is what surfaces trace findings in the first place; it’s also what lets us stand behind exactly what’s in the bottle.

Curious how we evaluate every product we sell? See how we execute on quality.