Skin Cancer Expert Shares 5 Sunscreen Tips

Skin cancer specialist Dr. Rachel Neale explained that the amount of sunscreen needed to achieve optimal protection is roughly one ounce—about the size of a shot glass—for full-body coverage, and a quarter‑teaspoon for the face and neck. She advises applying the product 15 to 30 minutes before sun exposure to allow the active ingredients to bind to the skin, and stresses the importance of reapplying at least every two hours, or more frequently after swimming, sweating, or towel‑drying. Neale noted that the American Academy of Dermatology recommends using broad‑spectrum SPF 30 or higher, and that consistent use can reduce the risk of melanoma and non‑melanoma skin cancers, which continue to rise in the United States.

While emphasizing the protective benefits, Neale acknowledged potential downsides, such as skin irritation from certain chemical filters, the rare occurrence of allergic reactions, and a modest reduction in vitamin D synthesis due to blocked UVB rays. She cautioned that these issues are generally manageable by selecting mineral‑based formulations for sensitive skin and monitoring vitamin D levels with a healthcare provider. Overall, Neale concluded that proper quantity, timing, and regular reapplication of sunscreen remain the most effective strategy for minimizing UV‑related skin damage.