Background:With more than 200,000 new cases per year, skin tumours have been the most frequently reported cancers in Germany for years. We performed a systematic review to summarise the current evidence concerning the preventive value of regular sunscreen use. Methods: Systematic literature review of controlled and randomised controlled trials were performed in Ovid Embase and Ovid Medline on 21 January 2020. We included studies evaluating the effectiveness of sunscreens on epithelial skin cancer, actinic keratosis or photoageing, or side effects in humans. Results: Five eligible trials, each involving 28 to 1,621 participants from various populations, were identified. All 4 studies on actinic keratoses showed a significant beneficial effect of sunscreens. The 2 studies on squamous cell carcinoma demonstrated significant beneficial effects of sunscreens. The 2 studies on photoageing observed a significant reduction in the sunscreen groups. The 2 studies on basal cell carcinoma reported no significant results, but both studies reported some non-significant protective effects of sunscreen use. Sunscreens as well as vehicles sometimes had side effects affecting skin and eyes. Compared with controls, sunscreens had no significant side effects on vitamin D, bone mass density and mortality. Conclusion: The evidence from published controlled and randomised controlled studies is limited. Especially for basal cell carcinoma, further high-quality studies including young populations are required to investigate possible protective effects of modern broad-spectrum sunscreens. The results of this systematic review do not change the current recommendations for UV protection. Sunscreens are recommended as a second-line measure against solar radiation whenever protective clothing and seeking shake are inadequate.