Spray sunscreen is a popular alternative to traditional lotions, offering a quick and convenient way to cover large areas of skin. This ease of application often leads to confusion about the correct technique for ensuring adequate sun protection. Many users assume a simple, light misting is enough, which is a misconception that leaves skin vulnerable to ultraviolet (UV) damage. Understanding the mechanics of spray application is fundamental to achieving the protection level stated on the product label.
The Necessity of Rubbing for Protection
The definitive answer is that spray sunscreen must be thoroughly rubbed into the skin after spraying to ensure maximum effectiveness. The SPF rating is determined through laboratory testing where the sunscreen is applied at a specific thickness of 2 milligrams per square centimeter (2 mg/cm²) of skin. This precise amount is difficult to achieve with a spray alone.
When sunscreen is sprayed from an aerosol can, it is propelled by gases, resulting in an uneven layer of product landing on the skin. This application frequently results in a much thinner and patchier film compared to a lotion or cream. Rubbing the product into the skin helps to evenly distribute the active ingredients, creating a uniform protective barrier.
Without rubbing, the resulting sun protection factor is often significantly lower than the advertised number, leaving skin exposed to harmful UV radiation. The physical act of spreading the sunscreen ensures the required film thickness is present across the entire exposed area. Skipping this step gives a false sense of security.
Proper Spray Technique for Even Coverage
Achieving an adequate layer of sunscreen begins with the correct spraying action. The can should be held relatively close to the skin, ideally between 4 to 6 inches away from the surface. Spraying from too far away allows the wind to carry away a significant amount of the product, resulting in less sunscreen landing on the skin.
The goal is to spray until a visible, wet sheen appears on the skin, not just a faint mist. A quick, light pass is insufficient; each body area should be sprayed continuously for about four to six seconds. This generous application creates the necessary wet layer that can then be manually distributed for complete coverage. If the layer is invisible after spraying, too little product has been applied to spread effectively.
The spray should be applied in a continuous, overlapping motion to ensure no gaps are missed. After creating this visible wet layer, the immediate step is to rub the product in completely. This technique prepares the layer for uniform coverage, which is necessary to realize the full SPF potential.
Safety and Handling Guidelines
Specific safety precautions must be followed when using aerosol spray sunscreens. Avoid spraying the product directly onto the face, as inhaling the mist can cause irritation to the lungs and throat. Instead, spray the sunscreen into your hands first, and then apply it to the facial skin like a traditional lotion.
Aerosol products contain flammable propellants like butane or propane. Users must never apply spray sunscreen near an open flame, such as a grill, candle, or while smoking. Ensure the can is shaken vigorously before use to evenly mix the protective ingredients, which may settle at the bottom of the container.