According to the U.S. Centers for Disease Control and Prevention (CDC), it is fine to use these products together. The CDC advises that people should apply sunscreen first and insect repellent second. In general, CDC recommends use of separate insect repellent and sunscreen products. However, the CDC also notes that a sunscreen’s SPF level may decrease when a DEET-containing insect repellent is applied after sunscreen, so people may need to reapply sunscreen more frequently if using the products in combination.