What Is a Sunscreen?

Sunscreens are FDA-approved over-the-counter products that help prevent skin cancer, wrinkles, and other signs of aging when combined with other sun safety measures. They protect against the UVA and UVB rays of the sun.


Mineral sunscreen ingredients (such as titanium dioxide and zinc oxide) act as a physical barrier to the sun, reflecting or scattering UV rays.

Broad-spectrum protection

A sunscreen is a skin-care product that protects the body from harmful UVB and UVA rays. UVB rays cause sunburn, while UVA rays penetrate deeper into the skin and are associated with premature aging and certain types of skin cancers. To prevent these damaging effects, a broad-spectrum sunscreen is essential. Look for a sunscreen that lists “broad spectrum” on the packaging and contains a combination of UVA-screening ingredients, such as zinc oxide, octinoxate, octisalate and titanium dioxide.

Until recently, scientists didn’t fully understand the damage caused by UVA rays. However, as they gained knowledge of the issue, manufacturers began to include sunscreens that guard against both UVA and UVB rays. Today, you can be sure a sunscreen offers broad-spectrum protection if it has the phrase “broad spectrum” on its label and an SPF of 15 or higher.

You should apply a generous amount of sunscreen before going outdoors. Make sure to cover all areas of the skin, including your ears, nose, neck and hands. Sunscreen should be reapplied every two hours, or more often if sweating or swimming. In addition, a sunscreen with UVA and UVB protection should contain skin-restoring ingredients such as soothing niacinamide and ceramides to help restore your skin’s natural protective barrier. Additionally, you should also choose a sunscreen that is water resistant.

UVA/UVB protection

UVA and UVB rays are emitted by the sun and can damage the skin. UVA rays are longer and penetrate deeper into the skin, which is why effective sun protection should be balanced, including both UVA and UVB. UVB rays are responsible for burning the top layer of the skin and are the main cause of sunburns, but also play a role in developing the most serious type of skin cancer, melanoma.

Sunscreens should be reapplied generously and regularly, especially after swimming or sweating, as per the manufacturer’s instructions. Daily application of a high-quality broad spectrum sun protection product decreases the risk of UV-induced oxidative stress and prevents premature skin ageing.

The ANTHELIOS range from La Roche-Posay Dermatological Laboratory includes sunscreens that provide effective UVA and UVB protection for all types of sensitive skin. The products are formulated to be gentle and have been tested to ensure that they do not irritate the skin, even when reapplied frequently or after prolonged exposure to sunlight. The products are enriched with anti-oxidants such as Baicalin, for boosted long UVA protection.

Moisturizing properties

Sunscreens offer moisturizers that can help soften dry skin, improve texture and prevent flakiness. They also help to minimize the appearance of wrinkles, dark spots and sagging skin.

Some sunscreens contain physical blockers, such as titanium dioxide or zinc oxide. These minerals sit on the surface of the skin and reflect UV rays away from the body, “a lot like a mirror or shield would,” George says. Others contain chemical absorbers, such as ensulizole, homosalate, octisalate, oxybenzone and octocrylene, which work by absorbing the sun’s rays into the skin’s cells. However, these ingredients are absorbed into the bloodstream and can cause allergic reactions in some people, says George.

Another common ingredient in sunscreens is octocrylene, which helps protect against sunburn and has emollient properties. But recent research suggests that octocrylene may be harmful to marine life, such as coral, and may cause damage to skin tissue.

A good sunscreen should be applied every hour, or more frequently if swimming or perspiring. The manufacturer’s instructions should be followed. Also, it’s important to keep in mind that even high-sun protection products should not be used as a substitute for sun-protective clothing, such as long-sleeved shirts and pants. This will help to reduce the risk of skin cancer and premature aging.

Environmental safety

Sunscreens protect against the damaging effects of UVA and UVB radiation. This is accomplished by absorbing and reflecting the radiation, or physically blocking it with ingredients such as titanium dioxide and zinc oxide. However, some sunscreens contain harmful chemicals that can damage the environment and human skin. For example, oxybenzone, an ingredient in many popular sunscreens, has been linked to coral bleaching and slows the growth rate of baby corals. It can also cause deformities in marine animals. It is possible to find reef-safe sunscreens that do not contain oxybenzone.

A few scientific studies have shown that certain chemical sunscreen ingredients can contaminate the environment and biomagnify in the food chain. These chemicals are absorbed by the body’s fatty tissues and can enter the bloodstream, where they can affect hormone levels. This is known as bioaccumulation. Some of these chemicals have also been found in the bodies of top predators, such as whales and seals.

The best way to protect your skin is to cover up with a wide-brimmed hat, umbrella, or long-sleeved shirt. In addition, a good quality sunscreen can help reduce the risk of cancer and early skin aging. A sunscreen with an SPF of 30 or higher is recommended.