I grew up in San Diego, California, where sunburns were almost as ubiquitous for me as the sun itself. The statistic that just five sunburns double your risk of melanoma has always scared me, because I’ve had more sunburns over the course of my life than I care to count.

To be clear, I always wear sunscreen and have never been in a tanning bed, but summers of surf camp and Junior Lifeguards and laying out at the beach have taken their toll. I get full body skin cancer checks once a year, and wear moisturizer with sunscreen on my face every day, but I have wondered how the damage that’s been done compares to the damage of tanning beds, or even alternatives like lotions and spray tans. Do the chemicals in alternative methods pose any dangers of their own?

Here’s a rundown of the health risks of a multitude of tanning methods.

Tanning outdoors

Light from the sun, or ultraviolet radiation (UVR) has been categorized as a Group 1 carcinogen by the World Health Organization. According to a review of tanning methods published in the Journal of Clinical and Aesthetic Dermatology in February 2015, "In addition to skin cancer, UVR is also responsible for premature aging, photodamage, fine lines, wrinkles, lax skin, and brown spots." To avoid skin damage, the American Academy of Dermatology recommends using water resistant sunscreen that offers broad-spectrum protection and an SPF of 30 or greater, and reapplying every two hours, or after swimming or sweating heavily.

It’s true that the Vitamin D present in sunlight can have health benefits, especially in colder weather when seasonal affective disorder is more common (research has found that an hour walk outside in the morning is enough to decrease the stress hormone cortisol).

However, oftentimes experts recommend avoiding the sun altogether to avoid harmful rays, which I’ve always found somewhat impractical. If you are going to be at the beach or pool in the middle of the day, in addition to applying sunscreen early and often enough, wearing a hat and bringing an umbrella can help protect from sun damage.

Tanning beds

A 2009 study found that college students are well aware of the dangers of tanning beds, yet many young adults continue to use them regardless. The United States Food and Drug Administration (FDA) strongly recommends that minors under 18 avoid tanning beds. In 2011, California became the first state to ban tanning beds for minors under 18. Tanning beds have been classified as a Class II medical device and are required to include labeling that identifies the risks of skin cancer.

A 2014 study reported that 35 percent of American adults and 59 percent of college students have used a tanning bed in their lifetime. Annually, over 400,000 cases of skin cancer are linked to indoor tanning. Tanning beds, which use man-made UVR light, can increase an individual’s risk of developing melanoma by 20 percent after just one session.

Tanning lotions

Tanning lotions use dihydroxyacetone, or DHA, a sugar molecule from plants that reacts with the top layer of the skin to produce pigment. DHA appears in tanning lotions in concentrations typically ranging from three to five percent. DHA has not been proven to be dangerous unless ingested, so should be kept away from the eyes and mouth. Tanning lotions take around two to four hours to take effect, and may continue to work for up to 72 hours. Tans last three to seven days with normal skin exfoliation, and less time with scrubbing or “prolonged water submersion.”

It’s important to note that tanning lotions are not a substitute for sunscreen—tanned skin can still burn, and those using tanning lotions should apply sunscreen in the same manner as anyone else. According to a 2002 study, allergic reactions to self-tanning lotions containing DHA are rare but have been reported. Consumers can report adverse reactions from cosmetics to the FDA here.

Spray tans

DHA has not been approved by the FDA in spray tanning booths because of the risk of ingestion. "Reported side effects from DHA-containing spray tans include rashes, cough, dizziness, and fainting," according to the February 2015 overview of tanning methods. "Some physicians have expressed concern that chronic exposure to spray tans may increase the risk of pulmonary disease, including asthma, chronic obstructive pulmonary disease (COPD), and cancer."

Many spray tanning facilities, however, still use DHA, since the FDA has approved it for external use, though it has not specifically as an "all-over spray." The FDA website explains:

"DHA is listed in the regulations as a color additive for use in imparting color to the human body. However, its use in cosmetics--including sunless 'tanning' products--is restricted to external application (21 CFR 73.2150). According to the CFR, 'externally applied' cosmetics are those 'applied only to external parts of the body and not to the lips or any body surface covered by mucous membrane' (21 CFR 70.3v). The industry has not provided safety data to FDA in order for the agency to consider approving it for use on these exposure routes, including 'misting' from tanning booths."

One such DHA-using facility offers eyewear, nose plugs, and lip balm, and directs potential customers to the FDA regulations, which state, "The industry has not provided safety data to FDA in order for the agency to consider approving it for use on these exposure routes, including 'misting' from tanning booths."

The FDA advises that consumers ask the following questions when considering using a spray tan facility with a DHA mist:

• Are consumers protected from exposure in the entire area of the eyes, in addition to the eyes themselves?
• Are consumers protected from exposure on the lips and all parts of the body covered by mucous membrane?
• Are consumers protected from internal exposure caused by inhaling or ingesting the product?

Pregnant women should consult with their physician before getting a spray tan.

Tanning pills

I had never heard of tanning pills before researching this article, which may be because none are approved by the FDA for use in the United States. The FDA has banned pills that contain canthaxanthin (which is used to color food, but in tanning pills may cause hepatitis and gastrointestinal disturbance) and pills containing tyrosine (which may aid in the production of melanin, but is considered by the FDA to be dangerous). Another type of tanning pill contains beta-carotene, which can be ingested naturally through fruits and vegetables and contributes to yellow skin tone. High doses of synthetic beta-carotene, however, may be correlated with elevated risk of lung cancer among smokers.