Ahead, we tapped two dermatologistsâ€”Loretta Ciraldo, MD, FAAD, and Michele Green, MDâ€”to explain how sunscreen works and to answer the burning question: Does sunscreen stop you from tanning? We deliver the truth about the one type of healthy tan.
Meet the Expert
- Loretta Ciraldo, MD, FAAD, is a Miami-based board-certified dermatologist with more than 40 years of experience. She is the founder of Dr. Loretta Skincare.
- Michele Green, MD, is a board-certified cosmetic dermatologist based in New York City, where she treats patients for sun damage, sun spots, and sun spot removal.
How Does Sunscreen Work?
The active ingredients of sunscreen, listed separately on SPF labels, work in one of two ways. Ciraldo explains: "Chemical sunscreen actives (also, confusingly called 'organic' actives) work by absorbing. Mineral actives (zinc and titanium) work mostly by reflecting ultraviolet rays before they penetrate into skin cells."
Green notes that "sunscreen works by blocking and absorbing harmful ultraviolet (UV) rays that would otherwise be absorbed by your skin, causing skin damage like sunburns and potentially skin cancer." She echoes Ciraldo, explaining further that the "physical and chemical properties work together to inhibit UV rays from penetrating your skin. Many sunscreens contain physical components like zinc oxide and titanium dioxide, which reflect UV radiation off the skin. Other chemical components of the sunscreen like avobenzone interact directly with the radiation to absorb the rays through their chemical bonds and release the energy as heat."
There are a couple of factors that inhibit sunscreen from working. "The most common problem with sunscreen is that we tend not to apply enough product to bring our skin up to the level of protection listed on the [tube]," explains Ciraldo. "For example, to cover our faces adequately we really should apply a full two fingers breadth worth of product, but most of us apply considerably less. So... we end up with a lower amount of sun protection than stated on the label."
Green adds that using expired or improperly stored sunscreen might prevent its efficacy. "Sunscreens usually have an expiration date, and once that expiration date has passed, the sunscreen begins to break down and may no longer be as protective against the sun as it was before," she says. "In addition, sunscreen needs to be stored in a cool, dry place. When sunscreen is stored at high temperatures, the sunscreen becomes less stable and eventually starts degrading."
Will Sunscreen Prevent You From Tanning?
Green explains that tanning is caused by exposure to UV radiation by either the sun or by tanning beds. "The UV radiation causes genetic damage to the epidermis or outer layer of the skin." Then, she explains, "the body tries to combat this damage by producing melanin, the pigment that gives our skin its color. This is what gives us what we call a tan. Sunscreens work by blocking UV radiation and preventing skin damage and are thus incompatible with tanning."
According to our experts, sunscreen does prevent you from tanningâ€”and you want it to, since this means it is doing its job. "The answer is almost always yes," says Ciraldo. "Sunscreen prevents tanning. Tanning is caused mostly by UVA rays and if we are using a broad-spectrum, UVA/UVB product most of us will not tan. The exception is someone who is heavily pigmented to start, where even minimal amounts of UVA that the SPF may permit through will tan [their] skin."
Can Sunscreen Inhibit Vitamin D Intake?
Many people think that regular sun exposure can provide enough vitamin D. But our experts explain that it's actually a little more complicated. "Sunlight exposure triggers the conversion of 7-dehydrocholesterol into previtamin D3 and ultimately into vitamin D3," explains Green. And Ciraldo adds that even though sunscreen does "block the skin's ability to synthesize vitamin D, sunbathing alone is never enough for us to produce a healthy level of vitamin D."
So although "sunscreen can potentially inhibit vitamin D intake," explains Green, "one randomized controlled trial in Australia found no difference in vitamin D levels between adults assigned to use sunscreen and another group assigned to use a placebo cream." She concludes that the risk of "prolonged sun exposure does not outweigh the benefits of getting vitamin D."
And Ciraldo adds that she advises everyone to "ingest 5,000 IU units of vitamin D3 each day. It's best to ask your physician to do a blood test to check your vitamin D3 level to be sure you aren't deficient in this important vitamin." She goes on to say that although "sunlight has many benefits on our mental health, I never recommend getting any amount of sun without sunscreen on our skin."
Is It Possible to Tan Safely?
Ciraldo says dermatologists always say that there's no such thing as tanning safely.
"People cannot tan safely since skin damage is cumulative," says Green. "According to the Skin Cancer Foundation, there is a 75 percent increased risk of developing life-threatening melanoma from just one indoor tanning session before age 35. There is no safe or healthy tan and any amount of tanning not only raises your chances of getting melanoma but also other skin cancers like basal cell carcinoma and squamous cell carcinoma."
Even short amounts of exposure to sunlight without sunscreen can be detrimental to your health, according to Green. "I do not recommend getting sun without sunscreen," she says. "Since your risk of skin damage varies [depending on] how strong the UV rays are and your skin tone, it is easy to get too much sunlight." She goes on to emphasize that "even if you are out for short periods of time without sunscreen, this can cause skin damage."
Both our experts agree that self-tanners are the only way to "do" a safe tan. Green notes that if you do apply a self-tanning product, especially a tinted oil, "always make sure youâ€™re applying sunscreen with an SPF of 30 and above before going outside." Consider what type of formula appeals to you when selecting a self-tanner.
- Mousse: "I recommend Jergens's Natural Glow Instant Sun Tanning Mousse ($11)," says Green. "This product is lightweight, airy, and dries within 60 seconds, making it quick and easy to apply. Many consumers rave about how flawless and natural this product looks on the skin." Oil: When it comes to oils, Green favors Josie Maran's Argan Liquid Gold Self-Tanning Oil ($40). "This product creates a natural-looking bronzed glow while revitalizing the skin with nourishing ingredients. It contains argan oil, coconut water, and aloe vera juice to keep your skin feeling and looking healthy and hydrated."
- Foam: You can also try a foam formula. Green likes Bondi Sands's Self Tanning Foam ($24). "This product applies evenly and streak-free to the skin," she says. "In addition, Bondi Sands's formulas contain aloe vera and coconut, which nourish the skin and leave behind a fresh coconut scent." Lotion: The classic lotion self-tanner is also a derm-approved pick. Ciraldo likes Jergens's Natural Glow ($10), which you can choose based on skin tone. "It works a little differently than most self-tanners because you use it every day and the tan builds over time," she says. "In this way, you have much less risk of a streaky look or skipped areasâ€”looking like strips of tan and lighter skinâ€”that can so easily happen with most self-tanners."
The Final Takeaway
Because sunscreen works to physically and/or chemically block harmful rays, it's a necessity for going out in the sun. Dermatologists do not advise getting sun without sunscreen and insist there's no such thing as a healthy tan. But this doesn't mean we have to give up the benefits and pleasure of sunlight. "Living in Miami Beach for nearly forty years I enjoy going outdoors and spending time in the sun," says Ciraldo. "Using SPF does not block the psychological benefits of the sun. We need to avoid getting sunburned because this presents the greatest risk for the development of skin cancer in addition to visible aging changes, including wrinkles and age spots."
Marks R, Foley PA, Jolley D, Knight KR, Harrison J, Thompson SC. The effect of regular sunscreen use on vitamin D levels in an Australian population. Results of a randomized controlled trial. Arch Dermatol. 1995;131(4): 415-421.
Tanning. The Skin Cancer Foundation.
Watts CG, McLoughlin K, Goumas C, et al. Association between melanoma detected during routine skin checks and mortality. JAMA Dermatology. 2021;157(12): 1425-1436.