What is it?
An extract of St. John’s wort (Hypericum perforatum), a flowering plant best known as an herbal supplement. Cosmetic extracts are made from the flowering tops, or the whole plant, using water, alcohol, glycols, glycerin or plant oils. It is used in very small amounts in creams, lotions and shampoos as a skin-conditioning and antimicrobial ingredient. It contains hypericin, a pigment that can make skin more sensitive to light.
Key information
- The CIR Expert Panel concluded in 2013 that St. John's wort extracts are safe as used in cosmetics, where reported use levels were at most 0.07 percent.
- Hypericin, a pigment in the plant, is a photosensitizer, but the Panel judged exposure at cosmetic use levels to be below the threshold of toxicological concern.
- The well-known drug interactions come from taking St. John's wort by mouth, which can weaken the effects of many medicines.
More information
St. John’s wort contains hyperforin, flavonoids such as quercetin compounds, and the pigments hypericin and pseudohypericin, which make up roughly 0.06 to 0.4 percent of the dried herb. In animals the plant is a known photosensitizer, because hypericin absorbs visible light and causes light-activated skin damage.
The Cosmetic Ingredient Review (CIR) Expert Panel first found the data insufficient in 2001. After new data arrived, including light-sensitivity tests, it concluded in 2013 that St. John’s wort-derived ingredients are safe in the present practices of use and concentration. A product containing 1.1 percent extract did not cause light sensitivity in guinea pigs, and St. John’s wort oil was not phototoxic by standard measures in eight volunteers. The Panel noted that hypericin is a photosensitizer, but because reported use levels were at most 0.07 percent, it concluded exposure would be below the threshold of toxicological concern. It cautioned against stacking botanicals that contain hypericin.
Reality check: most warnings about St. John’s wort concern taking it by mouth. As a supplement it can weaken the effects of many medicines, including birth control pills, some antidepressants, the blood thinner warfarin and HIV drugs. In one study cited by CIR, two weeks of oral use cut the amount of midazolam, a drug cleared by CYP3A enzymes, reaching the blood to 55 percent of normal. The NIH’s National Center for Complementary and Integrative Health (NCCIH) also says large oral doses, or the herb applied to the skin, might cause severe skin reactions after sun exposure. Supplement studies used doses such as 300 mg of extract three times a day; cosmetics contain at most 0.07 percent.
On labels, look for Hypericum Perforatum Extract, Hypericum Perforatum Flower/Leaf/Stem Extract or Hypericum Perforatum Oil. NCCIH advises anyone taking medicines to talk with a health care provider before using St. John’s wort.
Sources: CIR: Amended Safety Assessment of Hypericum Perforatum-Derived Ingredients as Used in Cosmetics (2013); NIH National Center for Complementary and Integrative Health: St. John’s Wort: Usefulness and Safety
