Spray sunscreens are popular for their convenience, offering quick application via an aerosol can. This format allows for rapid coverage of large body areas without the mess of traditional lotions, making reapplication easier. However, this unique delivery system, which releases a fine mist, raises questions about potential health risks and whether convenience compromises effectiveness.
The Primary Safety Concern: Inhalation Risk
The most significant safety concern unique to spray sunscreens is the risk of accidentally inhaling the aerosolized particles during application. When delivered as a fine mist, active and inactive ingredients are dispersed into the air and can be breathed into the lungs. While ingredients like zinc oxide and titanium dioxide are safe on the skin, their safety profile changes when they enter the respiratory system. Inhaling these substances, especially nanoparticles, introduces foreign particulate matter into the lung tissue.
This exposure can irritate the mouth, throat, and lungs, potentially causing coughing or triggering respiratory attacks in individuals with conditions like asthma. The Food and Drug Administration (FDA) has expressed concern about the potential long-term effects of inhaling these UV filter chemicals because manufacturers have not provided necessary data. The risk is heightened for children, who are more prone to accidental inhalation due to movement during spraying. Experts caution against using spray sunscreens on young children until the FDA determines the safety of the inhaled ingredients. Additionally, some aerosol sunscreens have faced recalls after testing revealed contamination with benzene, a known human carcinogen.
Ensuring Effective Protection: Coverage and Application
A practical concern with spray sunscreens is the difficulty in applying a sufficient and even layer to achieve the listed Sun Protection Factor (SPF). Effectiveness is measured based on applying two milligrams of product per square centimeter of skin, a thickness challenging to achieve with an aerosol.
The visible cloud often misleads users into believing they have applied enough, when much of the sunscreen is lost to the air or carried away by wind drift. Users frequently fail to spray long enough or rub the product in, which is necessary to create a continuous protective film. This under-application compromises the stated SPF and increases the risk of sunburn.
Dermatologists note that spray application often results in missed spots and thin coverage compared to lotion. To achieve comparable protection, the skin must appear fully saturated and glistening after spraying, and the product must then be thoroughly rubbed in. Without this critical step, protection remains uneven and inadequate.
Ingredients and Delivery Systems: What’s in the Can?
The physical differences between a spray and a lotion stem from the delivery system, which combines the sunscreen formulation with specialized propellants. Spray sunscreens are packaged in pressurized aerosol cans containing the active UV filters suspended in an emulsion, along with volatile chemicals.
The propellants are typically hydrocarbon gases, such as propane, butane, and isobutane, compressed within the can. When dispensed, these propellants rapidly expand and vaporize, breaking the mixture into the fine mist. While generally safe for external use, these propellants are highly flammable.
Many spray formulations also contain alcohol, which helps the product dry quickly and contributes to the aerosol effect. While appreciated for its non-greasy feel, this rapid-drying property introduces a flammability risk, with incidents reported where application near open flames resulted in serious burns.
Safe Usage Recommendations and Regulatory Stance
Despite the known concerns, spray sunscreens are widely available, and consumers should follow specific application guidelines to minimize potential risks.
Safe Application Guidelines
To avoid inhaling the mist, never spray the product directly onto the face. Instead, spray it into the hands first and then manually apply it to the facial skin. Hold the canister close to the skin and spray until the area is visibly wet before rubbing the product thoroughly into the skin to ensure sufficient coverage. Application should be done in a well-ventilated area to reduce the concentration of airborne particles, and spraying should be avoided around individuals with respiratory sensitivities. Due to the flammability of the propellants, users must ensure they do not apply spray sunscreen near an open flame, a lit cigarette, or any heat source.
Regulatory Status
The FDA currently regulates spray sunscreens as over-the-counter drugs, meaning they are approved for sale. However, the agency has requested additional data from manufacturers regarding the safety and efficacy of these products, specifically focusing on the inhalation risk. The FDA recommends caution, particularly advising parents to avoid using spray sunscreens on children until the necessary safety data on inhaled particles is fully evaluated.