Mixing DEET and Sunblock Increases Health Risks

A study from Canada's University of Manitoba warns against using DEET based mosquito repellents with sunblock.

The study, by professor of pharmacy Xiaochen Gu, found that when a 2.5-per-cent solution of insect-repelling DEET was mixed with oxybenzone, a very common sun-blocking ingredient, the amount of DEET absorbed into the skin went from 9.6 per cent to 30.2 per cent.

DEET has been known to cause some serious side effects including heart palpitations, disorientation and even seizures. There is evidence that if sunblock and DEET are used together there may be an increased risk for stroke, headache and hypertension.

"This will certainly cause some safety concerns if both sunscreen and DEET are applied at the same time," said Dr. Gu, "especially for DEET, because we know it can cause some side effects, such as hypotension, disorientation and even seizure."