Fernblock / PLE / Calaguala / Anapsos
An oral extract of the tropical fern Polypodium leucotomos (sold as Fernblock and other brands), studied since the 1990s as a systemic photoprotectant. Small human trials show it modestly raises the skin's threshold for UV-induced redness and lowers UV-related DNA damage, and a 2013 JAMA Dermatology trial found it a useful adjunct — alongside sunscreen and hydroquinone — for melasma. The evidence is real but limited: most studies are small, run in lighter skin types (Fitzpatrick I–III), and several are funded by the extract's makers. It supplements sunscreen, it does not replace it — it does not filter UV, it dampens the downstream damage. A reasonable, low-risk add-on for pigmentation-prone or photosensitive skin; not a magic pill.
Oral 240–480mg/day, ideally before sun exposure. An adjunct to daily sunscreen, never a substitute. Well tolerated; most evidence is in Fitzpatrick I–III skin.
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