Can herbal supplements contain hidden heavy metals and pesticide residues?

What's actually in it

Herbal supplements like Rhodiola rosea (a popular adaptogen for stress and energy) are sold in capsules, tablets, and powders. The herbs used to make these supplements absorb whatever is in the soil they grow in, including heavy metals like lead, cadmium, and arsenic. Pesticides sprayed during farming can also end up in the final product.

What the research says

A 2026 study in PLoS One tested Rhodiola rosea supplements sold on the U.S. market for quality, heavy metals, and pesticide residues. The researchers found that many products contained detectable heavy metals and pesticide residues. Some products also failed quality tests, containing less active ingredient than claimed on the label.

Since supplements aren't regulated as strictly as drugs, contamination can go undetected. People taking these supplements daily for months or years may be accumulating heavy metals and pesticides without knowing it.

Choose supplements that have been third-party tested by organizations like USP, NSF, or ConsumerLab. Look for brands that publish their heavy metal and pesticide testing results. Buy from reputable companies with transparent sourcing.