By  now, everyone should know that the sun is damaging to your skin, and that sunscreen should always be included in your daily skincare regimen; but how much thought do you actually put into what goes in to your sunscreen? Not all sunscreens and sun blocks are created equal, nor do they all contain the same active and inactive ingredients. It’s important to know your own skin type and sensitivities and buy sunscreen that is best suited to your skin, based on its ingredients.

The principal ingredient structure of sunscreen allows it to absorb high-energy ultraviolet rays and release the energy as lower-energy rays, thereby preventing the skin-damaging ultraviolet rays from reaching the skin. Here is a look at some of the common ingredients in sun care products and what they do:

Titanium Dioxide: A physical UV blocker that helps block both UVA and UVB wavelengths. It does not absorb into the skin, so it is non-irritating and hypoallergenic, making it appropriate for sensitive skin. While titanium dioxide gives good protection, it does not completely cover the entire UV-A spectrum.

Zinc Oxide: Another physical blocker that sits on the skin’s surface (is not absorbed) and blocks both UVA and UVB rays of ultraviolet light. Research suggests that zinc oxide is superior to titanium dioxide at wavelengths between 340 and 380 nm.

Avobenzone: An oil soluble ingredient used to absorb the full spectrum of UVA rays. Avobenzone can degrade faster with exposure to light in combination with mineral UV absorbers like zinc oxide and titanium dioxide, though with the right coating of the mineral particles this reaction can be reduced.

Oxybenzone: An FDA approved UVA absorbing chemical sunscreen ingredient. Oxybenzone has been the subject of some controversy as adverse health effects may be associated with the synthetic compound. In 2007, two studies by the CDC highlighted concerns about oxybenzone. The first detected the chemicals in greater than 95 percent of 2000 Americans tested, while the second found that mothers with high levels of oxybenzone in their bodies were more likely to give birth to underweight baby girls.

PABA(Para-Aminobenzoic Acid): Patented in 1943, PABA was one of the first active UVB absorber ingredients to be used in sunscreen, most commonly during the 1970s. However, it became a frequent cause of contact dermatitis, causing it to fall out of favor. Water-insoluble PABA derivatives such as octyl dimethyl PABA are still currently used in some products.

Vitamins A, E and C: Sunscreens manufacturers are following the trend of adding in a variety of antioxidants to help try to neutralize cellular DNA damage where it’s starting (from sun exposure that makes its way through your sunscreen) or help rejuvenate your skin. For those who are looking to avoid vitamin A, particularly if pregnant or nursing, add this to your list of product label reading.

New Kids on the (Sun) Block

In recent years, new sunscreen ingredient combinations have come to the forefront, offering high performance alternatives. Neutrogena is now marketing a complex called Helioplex (contained in their sunscreens such as Neutrogena Ultra Sheer Dry-Touch SPF 55). Helioplex is a blending of commonly used sunscreen agents (including oxybenzone) and avobenzone with the spin that a new technology has made this formulation more photo-stable.

The list of UVA protectors has expanded with the recent FDA approval of Mexoryl, a blend of avobenzone, octorcrylene and newcomer ecamsule. Ecamsule has been on European store shelves since the early 90s and offers an alternative for anyone with a sensitivity to other sunscreen ingredients. Sunscreens containing ecamsule are exclusive to L’Oréal and its brands.

Like any other skin care product, your sunscreen should be selected based on your specific skin type and any skin conditions or sensitivities you have. Knowing what is in your sunscreen can help you avoid negative reactions. For help selecting the best sunscreen for your skin, try our handy Sunscreen DERMAWizard tool.