While the strategy for comprehensive photoprotection of seeking shade, wearing photoprotective clothing, wide brimmed hat and sunglasses, and applying sunscreen to otherwise exposed sites is well-established, oral and systemic photoprotection has been studied for many years. For example, down regulation of UV-induced cutaneous changes has been described for Polypodium leukotomos since the mid 1990s, and for green tea since at least 2003. In 2015, a phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention was published, and the effective of subcutaneous implant of afamelanotide in patients with erythropoietic protoporphyria (EPP) was reported.
Compared to topical measures and behavioral modification, the advantage of oral photoprotection is its convenience. However, currently, all the oral photoprotective agents should be used as adjunctive measures to the established photoprotection strategy. The sole exception is afamelanotide, which was approved by US FDA for EPP as subcutaneous implant on Oct 8, 2019.
As all the agents (except for afamelanotide) are over the counter preparation, judicious use might be helpful to partially down-regulate the side effects of sun exposure.