Sun sensitivity showed up only at or above what products deliver
Single doses at 900 and 1,800 mg changed nothing. Two weeks at 1,800 mg a day did raise ultraviolet sensitivity measurably, and that sits at the top of what products give.
What the study found
Sun sensitivity showed up only above the doses products sell
A label warning is not the same as an effect at the dose on the label. Single doses at 900 and 1,800 mg changed nothing; two weeks at 1,800 mg a day did raise ultraviolet sensitivity measurably. Every dose that moved the skin sat at or above the top of what products deliver.
The caveat · Lamp tests on back skin, not sunburn
Sensitivity was measured on small patches of back skin under standardised lamps, which is a laboratory endpoint rather than sunburn in ordinary life. The two-week arm had no placebo group and compared each person against himself. Blood levels of hypericin, the constituent products are standardised on, did not track photosensitivity at all.