An eight-week clinical trial found a protective benefit for an orally administered combination of red orange and fern extracts against the effects of damaging ultraviolet light. The nutrients could be used along with topically applied sunscreens to increase protection from excess sun exposure.

“While conventional photoprotection strategies—like using sunscreens, protective clothing, and limiting sun exposure—are essential, they have limitations, including inconsistent application, frequent reapplication requirements, and photostability issues, all of which contribute to suboptimal protection in real-world use,” the authors of the report wrote. “Given these limitations, recent studies highlight the benefits of oral photoprotection.”

At the beginning of the trial, and at two and eight weeks, participants were exposed to ultraviolet B (UVB) rays on their lower backs and the minimal dose of UV needed to cause redness was determined. In comparison with measurements obtained at the beginning of the trial, participants who received fern plus red orange showed an increase of 23.8% in the minimal dose of UVB radiation needed to produce skin redness and a 46.2% reduction in redness intensity (measured 24 hours following irradiation) at the end of the trial. The placebo group showed no significant effects. There were no differences in skin pigmentation observed between treatment and placebo groups at two weeks and at the end of the eight-week study, which indicates that the nutrient combination will not affect tanning response and that its benefits are not dependent upon the protective effects of melanin.

The randomized, double-blind, placebo-controlled trial included 27 men and women who received a combination of Polypodium leucotomos fern extract and red orange extract along with vitamins A, C, D and E, and 25 participants who received a placebo to be consumed daily for eight weeks.

The benefits of the nutrients were significant at eight weeks, which emphasizes the importance of sustained use. “This study supports oral supplementation as an adjunct to topical photoprotection, with prolonged use potentially yielding cumulative benefits,” the authors concluded.

The findings were reported April 2, 2025, in the journal Nutrients.¹