Q: Which goes on first – insect repellent or sunscreen?

A: According to the Centers for Disease Control and Prevention (CDC)  you should apply sunscreen first before lightly applying insect repellent. Usually about 15 to 20 minutes apart. The reason is that sunscreen is highly absorptive, therefore putting it on top of repellent may cause your skin to soak up more of the chemicals (such as DEET) in the repellent.

Furthermore while combination products may sound like a good and convenient idea, the CDC does not  recommended the use of  products that combine sunscreen and insect repellent containing DEET. This is because repellents usually don’t need to be reapplied as often and as generously as sunscreen. Also, when combined, the sunscreen may have decreased ability to screen out ultraviolet (UV) radiation due to the repellent, while the toxicity of the repellent may be increased by the sunscreen.