Spray sunscreen is a popular type of sun protection dispensed from a pressurized can, creating a fine mist that covers the skin. It is widely favored for its speed and convenience, especially for covering large areas or reaching difficult spots like the back. The ease of application has made it a common choice for parents, athletes, and anyone seeking quick sun protection. However, this convenience raises the question of whether it compromises the product’s fundamental purpose. This article examines the effectiveness of spray sunscreen and details the specific techniques and safety precautions required to ensure it provides the full protection stated on the label.
Efficacy: Spray Versus Lotion Protection
Spray sunscreens can deliver the Sun Protection Factor (SPF) and Broad Spectrum protection listed on their packaging, but their efficacy depends entirely on the user’s application technique. The Food and Drug Administration (FDA) regulates sunscreens, requiring them to meet strict standards for protection against both UVA and UVB rays. The core challenge with the spray format is achieving the specific film thickness required to deliver the advertised level of protection.
The official testing standard for sunscreen efficacy assumes an application thickness of two milligrams of product per square centimeter of skin. This amount creates a uniform barrier on the skin’s surface. Unlike traditional lotions, where users can visually confirm and manually spread the product, the aerosol format makes it difficult to judge how much product is actually landing on the skin, especially when compounded by environmental factors like wind.
Studies show that individuals typically apply significantly less product than required when using a spray, which dramatically reduces the actual protection received. A quick, light mist results in a thin and patchy layer, offering only a fraction of the protection indicated on the label. For a spray to be as effective as a lotion, the user must apply a generous and visible amount. The effectiveness of the product is compromised not by the formula, but by the method of delivery and the user’s perception of adequate coverage.
Ensuring Proper Application
Achieving the labeled SPF requires a deliberate and generous application technique. Dermatologists recommend holding the nozzle close to the skin, typically four to six inches away, to minimize product loss to the air. The skin should be sprayed continuously until a visible, wet, and glistening sheen appears across the entire area. This visual cue confirms that a sufficient volume of product has been deposited.
A common recommendation is the “four-second rule,” suggesting that each body section—such as a leg, arm, or the torso—needs four to six seconds of continuous spraying. This generous application is necessary because a significant amount of the mist can be lost to the air, especially outdoors. After spraying, it is essential to rub the product in thoroughly with your hands. Rubbing ensures the active ingredients are evenly distributed, filling in any gaps to form a uniform, protective film over the skin.
For optimal protection, the application should be done in layers, especially when covering a large area. It is best to apply the spray indoors or in a sheltered area to prevent the mist from being carried away by the wind. As with all sunscreens, reapplication must occur at least every two hours, or immediately after swimming or excessive sweating.
Unique Safety Concerns of Aerosols
The aerosol delivery system introduces unique safety concerns unrelated to UV protection. The primary health risk is the potential for inhalation of the product’s ingredients, including active UV filters and propellants. Breathing in these fine particles can irritate the mouth, throat, and lungs, which is a particular concern for individuals with respiratory conditions like asthma.
The FDA continues to review data on the long-term effects of inhaling spray sunscreen ingredients. While mineral ingredients like titanium dioxide and zinc oxide are safe on the skin, the risk increases when they are aerosolized and breathed deep into the lungs. To mitigate this risk, users should never spray the product directly onto the face; instead, spray a generous amount into the palm of the hand and apply it like a lotion.
Another safety consideration is the flammability risk associated with the aerosol format. Many spray sunscreens contain flammable propellants like butane or propane, as well as alcohol. Consumers should always check the product label for flammability warnings and ensure the product is completely rubbed in and dry before approaching any heat source or open flame.