PDF of Forum 0213

What are the two most important ingredients to look for in sunscreen? — Debbie Meckler, RN, BSN

The goal of sunscreen is to provide broad spectrum protection against UVA and UVB rays. A good chemical sunscreen includes ingredients that protect against both. Avobenzome and benzophenones (oxybenzone, dioxybenzone, sulisobenzone) are ingredients that protect against UVA rays. Aminobenzoic acid (PABA), benzophenones, menthyl anthranilate (also known as meradimate), padimate, and phenylbenzimidazole are ingredients that protect against UVB rays. Unlike chemical sunscreen ingredients, which absorb the sun’s rays, titanium dioxide and zinc oxide are physical sunscreens that actually reflect the UVA and UVB rays of the sun.

Mexoryl SX, also known as ecamsule, is the newest sunscreen ingredient approved by the FDA. It provides broad-spectrum protection against both UVA and UVB rays. Mexoryl SX is only used in high-end sunscreens, such as La Roche Posay Anthelios XL SPF 50 Cream and Lancôme UV Expert 20.

Helioplex is a name brand sunscreen stabilizer. It makes sunscreen ingredients more photostable so they do not break down when exposed to the sun.

Retinyl palmitate (vitamin A) and oxybenzone are sunscreen ingredients that are concerning to some parents. Although many experts claim these ingredients are safe, their safety is a common sunscreen controversy, and some parents choose to avoid them and look for sunscreens with different ingredients.

SPF stands for sun protection factor. It is mainly a measure of UVB protection and ranges from 1 to 45 or higher. The number is determined experimentally indoors by exposing human subjects to a light spectrum meant to mimic noontime sun. Some subjects wear sunscreen and others do not. The amount of light that induces redness in sunscreen-protected skin, divided by the amount of light that induces redness in unprotected skin is the SPF. A sunscreen with an SPF of 15 filters 92% of the UVB. A sunscreen with an SPF of 15 will delay the onset of sunburn in a person who would otherwise burn in 10 minutes to burn in 150 minutes. The SPF 15 sunscreen allows a person to stay out in the sun 15 times longer. There is currently no uniform measure of UVA absorption. There are broad-spectrum sunscreens that protect against UVA and UVB radiation although it is important to remember that the SPF does not predict UVA protection.

If the patient has sensitive skin, recommend a sunscreen that is PABA-free, fragrance free, and hypoallergenic. A physical sunscreen, with either zinc oxide or titanium dioxide, might also be an appropriate choice, instead of a sunscreen with chemical ingredients.

Other good suncreens include Neutrogena Ultra Sheer Dry-Touch Sunblock SPF with helioplex, Neutrogena UVA/UVB SPF 45, Blue Lizard Australian sunscreen, Solbar sunscreen, and Coppertone Sport Sunblock Gel SPF 30. —Sandra Cuellar, PharmD, BCOP