Sunscreen is designed to protect skin from ultraviolet (UV) radiation, not from biting insects. The short answer to whether sunscreen repels bugs is generally no, because the mechanisms used to block UV light have no inherent function as a pest control agent. Sunscreen is an important tool for preventing sunburn, premature aging, and skin cancer. Insect repellents are specifically formulated to interfere with an insect’s ability to locate a host. Using two separate products is the most reliable way to achieve both sun protection and bite prevention during outdoor activities.
UV Filters Versus Insect Deterrents
The fundamental difference between sunscreens and insect repellents lies in their chemical composition and intended biological targets. Sunscreens work by filtering or blocking specific wavelengths of light, while insect repellents act on the insect’s sensory system. Chemical sunscreens, such as avobenzone or oxybenzone, absorb UV radiation and convert it into heat. Physical sunscreens, like those containing zinc oxide or titanium dioxide, create a physical barrier that scatters and reflects UV light away from the skin.
These UV-filtering actions do not interact meaningfully with an insect’s chemoreceptors, the sensory organs insects use to detect carbon dioxide, heat, and human-specific odors. Insect repellents, such as DEET or Picaridin, function entirely differently. These chemicals emit vapors that confuse or overload the olfactory system of mosquitoes and ticks, preventing them from recognizing a human as a food source. The repellent is a sensory disruptor, not a light blocker.
The Source of the Confusion
The persistent belief that sunscreen might repel bugs often stems from anecdotal experience and sensory factors present in some formulations. Older sunscreen lotions could sometimes be heavy and thick, creating a physical coating that may offer a minimal, temporary impediment to some crawling insects. This physical barrier, however, is not a reliable defense against biting insects like mosquitoes.
Some sunscreens may also contain fragrance ingredients that lend a strong, sometimes citrus-like, scent. While some natural scents, such as oil of lemon eucalyptus, are registered as insect repellents, the small amounts of fragrance used in most sunscreens are insufficient to deter biting pests effectively. Applying a product with a noticeable odor outdoors can lead users to misattribute a temporary lack of bites to the sunscreen’s protective qualities. The perceived repellent effect is often minimal and does not offer the proven protection of an EPA-registered insect repellent.
Dual Protection: Using Sunscreen and Repellent Together
For optimal protection against both the sun and insects, applying both products separately is the recommended protocol. Experts, including the Centers for Disease Control and Prevention (CDC), advise applying sunscreen first, allowing 15 minutes to fully absorb and set on the skin. After the sunscreen is applied, the insect repellent should be applied gently over the exposed skin areas.
This application order is important because some sunscreen ingredients can increase the absorption of repellent chemicals, particularly DEET, into the skin. Applying sunscreen first mitigates this effect and ensures the UV filters form an uninterrupted protective layer. Studies have shown that mixing the two products or applying repellent first can significantly reduce the Sun Protection Factor (SPF) of the sunscreen, compromising sun protection.
Pre-mixed combination products containing both sunscreen and insect repellent are discouraged by public health authorities. Sunscreen requires frequent reapplication, typically every two hours, or more often if swimming or sweating heavily. In contrast, insect repellents, especially those with high concentrations of DEET, often last much longer, sometimes up to six to eight hours. Repeatedly applying a combination product to maintain sun protection can lead to unnecessary overexposure to the repellent chemical.
When applying insect repellent, use it only on exposed skin and outer layers of clothing. Take care to avoid cuts, wounds, and sensitive areas like the eyes and mouth. For facial application, spray the repellent onto your hands first and then carefully pat it onto the face. After returning indoors, washing the skin to remove the repellent is a simple safety measure.