How We Rate Ingredients

Every ingredient here gets one of four ratings: better to avoid, depends on the product, no real concern, or not yet rated. The rating reflects what the published evidence shows, weighed the same way for every ingredient. We don’t start from a list of “bad” chemicals and work backward. We read the evidence and let it decide.

What goes into a rating

A rating is never based on a single study or an ingredient’s reputation. Before anything gets rated, the evidence behind it gets pulled together from several directions at once:

• Human studies, where they exist.
• Lab and animal research on what the ingredient does in the body: effects on hormones, reproduction, organs, and cancer risk.
• What the independent scientific and regulatory bodies have concluded, and whether they agree.
• What happens to the ingredient once it is out in the environment, and whether it builds up in people or wildlife.
• Where it is restricted or banned, and why.

The bodies we check include the U.S. Food and Drug Administration, the European Commission’s Scientific Committee on Consumer Safety, the European Food Safety Authority, the European Chemicals Agency, Health Canada, France’s ANSES, California’s Office of Environmental Health Hazard Assessment, and the U.S. Agency for Toxic Substances and Disease Registry. When they disagree, we show the split instead of smoothing it over.

We correct the record in both directions

A lot of ingredient advice online treats every ingredient as guilty until proven innocent. We don’t. When an ingredient people worry about turns out to be fine at real-world use, we say so. When a popular “clean” claim doesn’t hold up, we say that too.

Two examples. Sodium lauryl sulfate (SLS) gets called a carcinogen all the time. It isn’t one. It is a known skin irritant, a real but much smaller issue, and that is what its rating reflects. Aluminum in antiperspirant runs the other way: it is widely tied to Alzheimer’s and breast cancer, and neither link is established by the evidence, but it still lands at better-to-avoid, because it accumulates in breast tissue and acts like a weak estrogen, which is reason enough to limit it on a sensitive spot. The rating rests on what the evidence supports, not the scarier claim it doesn’t, and not the reassurance either.

A rating that only ever points one way is not weighing evidence.

How sure are we?

Evidence is not equally settled from one ingredient to the next. So every rating carries a confidence level, which marks the difference between a verdict backed by decades of human data and one resting on early or limited research. Confidence is about how settled the science is. It does not soften the rating itself.

Who pays for this?

No ads, no affiliate links, no sponsors. No company pays to be rated, and no rating is shaped by any commercial relationship with the products it covers.

You can check our work

Every rating lists its sources. So you don’t have to take our word for any of it. Click through, read what we read, and weigh it yourself. Where experts still disagree, the rating says so instead of pretending the question is settled.

We update as the evidence changes

Science moves. When new research lands, a regulator shifts its position, or a stronger study comes out, the rating moves with it. A rating is our best read of the evidence today, not a permanent verdict.