Optimal sunscreen use, during a sun-holiday with a very high UV index, allows vitamin D synthesis without sunburn.

CONCLUSIONS: Sunscreens may be used to prevent sunburn yet allow vitamin D synthesis. A high UVA-PF sunscreen enables significantly higher vitamin D synthesis than a low UVA-PF sunscreen because the former, by default, transmits more UVB than the latter. This article is protected by copyright. All rights reserved.
PMID: 31069787 [PubMed - as supplied by publisher]

Source: The British Journal of Dermatology - May 7, 2019 Category: Dermatology Authors: Young AR, Narbutt J, Harrison GI, Lawrence KP, Bell M, O'Connor C, Olson P, Grys K, Baczynska K, Rogowski-Tylman M, Wulf HC, Lesiak A, Philipsen PA Tags: Br J Dermatol Source Type: research