Can you tan with sunscreen on? What happens

Many people put on sunscreen at the beach and still come home with a tan. Some are pleased and some are surprised. Either way, it raises two questions: how does sunscreen let a tan happen, and is a tan with sunscreen safer than a tan without it? This guide answers both with what the FDA, the American Academy of Dermatology (AAD) and the NHS say. It is part of Skinli's guide on how to choose a sunscreen for your face.

Why you can still tan with sunscreen on

The short answer is that sunscreen reduces ultraviolet light, and some still gets through. The FDA says, "No sunscreen completely blocks UV radiation. So other protections are needed, such as protective clothing, sunglasses, and staying in the shade."

The AAD gives the numbers for the burning rays:

SPF	Burning rays filtered out (AAD)	Burning rays that still get through
SPF 15	93 percent	7 percent
SPF 30	97 percent	3 percent

The AAD adds that "no sunscreen can filter out 100% of the sun's UVB rays."

Those numbers assume the amount of sunscreen used in the lab test. Real life is thinner. The AAD says many people apply only 20 to 50 percent of the amount needed to reach the SPF on the label. Add sweat, swimming, towels and missed spots, and more light gets through than the number suggests. Over a long day in strong sun, that is enough for many skin types to tan.

What a tan is

The FDA's page on the risks of tanning says: "There is no such thing as a safe tan. The increase in skin pigment, called melanin, which causes the tan color change in your skin is a sign of damage."

The FDA explains the process. Once skin is exposed to ultraviolet light, "it increases the production of melanin in an attempt to protect the skin from further damage." The darker color can develop over the next 48 hours.

MedlinePlus, from the U.S. National Library of Medicine, describes it more bluntly. Suntans "appear after the sun's rays have already killed some cells and damaged others."

The AAD's view is the same: "There is no safe way to tan. Every time you tan, you damage your skin. As this damage builds, you speed up the aging of your skin and increase your risk for all types of skin cancer." An AAD news release adds that the tan caused by the sun's UV rays "is a sign of skin damage."

A tan gives little protection

Some people try to build a "base tan" before a holiday, hoping it will stop them from burning later. The FDA addresses this directly. It says a tan will not protect your skin from sunburn or other skin damage, and that the extra melanin in tanned skin gives a sun protection factor of 2 to 4, "far below the minimum recommended SPF of 15."

The NHS agrees: "There's no safe or healthy way to get a tan. A tan does not protect your skin from the sun's harmful effects."

The FDA's consumer page on sun safety puts it this way: tanning is the skin producing extra pigment "that provides it with some, but often not enough, protection against sunburn."

Is a tan with sunscreen safer?

Sunscreen lowers the dose of ultraviolet light, and a lower dose means less damage. That is why the FDA and the AAD recommend it. But the sources do not describe any amount of tanning as safe. A tan that forms under sunscreen is still a sign that some damage happened.

The NHS gives a clear rule: "Do not spend any longer in the sun than you would without sunscreen." Use sunscreen to protect the time you would spend outside anyway, and keep that time the same.

If you want the look of a tan

The AAD's suggestion is simple. "If you want to look tan, you may wish to use a self-tanning product, but continue to use sunscreen with it." A self-tanner colors the outer layer of skin without ultraviolet light. It gives no sun protection, so sunscreen still goes on for time outdoors.

The AAD also advises avoiding tanning beds. It says "ultraviolet light from the sun and tanning beds can cause skin cancer and wrinkling."

Who tans and who burns

Skin reacts to the sun in different ways. The FDA says skin tones that can tan, "typically skin types II through V," will probably darken within two days. Those numbers come from a six-type scale that sorts skin by how easily it burns and how well it tans. Type I always burns and never tans. Type VI never burns and is deeply pigmented. Our guide to the Fitzpatrick skin scale explains each type.

Skin that tans easily can still be harmed. The FDA says people of all skin colors are at risk for sunburn and other harm from ultraviolet light. It asks for extra care if you have:

• Pale skin
• Blond, red or light brown hair
• Been treated for skin cancer
• A family member who has had skin cancer

The FDA also says some medicines can increase sun sensitivity, and suggests asking your health care professional about sun care if you take any.

Tanning beds carry their own risks

Some people see a tanning bed as a controlled way to tan. The NHS says sunbeds and lamps "can be more dangerous than natural sunlight because they use a concentrated source of UV radiation." In the UK it is illegal for anyone under 18 to use a sunbed. The AAD's advice is to avoid tanning beds completely, and its acne tips say to stay out of both the sun and tanning beds. The U.S. Department of Health and Human Services and the World Health Organization's cancer agency both list ultraviolet light from the sun and from tanning beds as a known cause of cancer, according to the AAD.

Tanning, acne and dark marks

People with acne sometimes notice their skin looks clearer after a few days in the sun, because a tan can hide redness. The AAD's acne advice says the opposite is true underneath: tanning "damages your skin and can worsen acne." Some acne medicines also make skin more sensitive to the sun.

Sun also affects the dark marks that pimples leave. The AAD says daily sunscreen can prevent new dark spots and help clear existing ones. For people with darker skin, the AAD says visible light from the sun can also darken skin, and recommends tinted sunscreen with iron oxide, which blocks visible light. Our guide on whether Black people need sunscreen covers this in more detail.

How to lower tanning and burning outdoors

The AAD's advice for time outside has four parts:

1. Seek shade, especially between 10 a.m. and 2 p.m. The AAD says if your shadow is shorter than you are, find shade.
2. Cover up with a lightweight long-sleeved shirt, pants, a wide-brimmed hat and sunglasses with UV protection.
3. Use sunscreen that is broad spectrum, SPF 30 or higher and water resistant, on all skin that clothing does not cover. Use enough: at least 1 teaspoon for the face.
4. Reapply every two hours outdoors, and after swimming or sweating. Our guide on how often to reapply sunscreen covers this.

Take extra care near water, snow and sand. The AAD says they reflect the sun's rays and raise the chance of sunburn. Clouds let most of the light through: the FDA says up to 80 percent of the sun's UV rays can get through on an overcast day.

When a sunburn needs a doctor

A mild sunburn usually heals on its own. The FDA says severe sunburn "should be treated as a medical emergency and examined by a doctor right away." It describes severe sunburn as a large area of red, blistered skin with a headache, fever or chills. The AAD says blistering means a second-degree sunburn, and that you should not pop the blisters.

The FDA also says that people with medium to dark skin may not see clear signs of sunburn until several hours later. Watch for pain and heat in the skin as well as redness.

For a quick look at the SPF numbers used here, see our guide on how sunscreen works and what SPF means. If you are on an acne treatment that raises sun sensitivity, such as a retinoid, see how to start adapalene without irritation for the sun rules that go with it.