Tan Lines Are Trending on Social Media—Here’s What Science Says About 'Safe Tanning'

Just when I thought the days of SPF 2 tanning oils and proudly scorched skin were behind us, TikTok and other social media platforms are fuelling a bizarre comeback of tan lines. The trend involves users actively seeking out tan lines by exposing their skin to harmful levels of UV, often burning themselves in the pursuit.

The trend is being fuelled by hashtags and the use of tanning apps like SunKiss AI, which describes itself as a "personal tanning coach" that provides users with "the perfect tanning routine based on your skin type and goals", using the device's location to estimate the UV index. Alarmingly, the app promises their users that if they follow the app's advice, they will be able to achieve a "gorgeous glow, while staying safe".

Unsurprisingly, the medical community doesn't agree. "There is no such thing as a healthy tan," says Consultant Dermatologist, Dr Derrick Phillips. "Tanning damages skin cells and can lead to development of skin cancer." Indeed, UV radiation (both from sun and sunbeds) is classified by the WHO’s International Agency for Research on Cancer as a Group 1 carcinogen (other examples of Group 1 carcinogens include tobacco smoking and asbestos), with no safe threshold for cosmetic exposure.

Such an enthusiastic attitude to tanning is difficult to understand, especially when so much progress had been made to educate people about the dangers of UV exposure. "Sun burn is more than a temporary inconvenience; it causes lasting damage to the skin," adds Dr Phillips. "Each episode of sunburn causes DNA damage at a cellular level. Over time this damage accumulates, increasing the risk of skin cancer, and accelerating the skin’s natural ageing process, resulting in fine lines, wrinkles and uneven skin tone."

Melanoma, the most serious form of skin cancer, can develop in new or existing moles, so it’s important to check your skin regularly and know what’s normal for you. "When a suspicious mole is removed, it’s usually excised in the shape of an ellipse, along with a 2mm margin of healthy skin," explains Dr Phillips. "This approach helps ensure the abnormal mole is fully removed and allows the resulting scar to heal in a straight line."

All removed moles are sent for laboratory testing to confirm the diagnosis and if melanoma is detected under the microscope, further treatment is often necessary. "This typically involves removing an additional 1-2cm of surrounding skin on either side of the scar. In some cases, nearby lymph nodes may also need to be assessed or removed, depending on the stage of the melanoma." In other words, following the tan lines trend on TikTok could leave you with a far more permanent—and much larger—mark than you ever bargained for.

Melanoma warning signs:

According to Dr Phillips, a helpful way to spot concerning changes is the ABCDE checklist:

• A = Asymmetry. Where one half of the mole does not match the over.
• B= irregular Borders. Notched, irregular or scalloped borders.
• C= Colour. The presence of multiple or uneven colours.
• D= Diameter more than 6mm
• E= Evolving. A mole that changes in size, shape and colour or starts to bleed.

If a mole shows two or more of these features, it’s best to have it reviewed by your GP or dermatologist.

Marie Claire reached out to SunKiss AI for comment but had not received a response by the time of publication.