A new trend that has gone viral on TikTok is worrying dermatologists. Influencers in several countries are promoting the so-called “Barbie drug”, a substance known as melanotan II, which they claim provides an intense tan without sun exposure.
However, experts warn that the product is not approved for cosmetic use and is banned in several states, including the United States, the United Kingdom, Australia and Denmark. However, the substance continues to be sold online as injections or nasal sprays, and videos promoting its effects garner millions of views.
“What is being sold on social media as a quick and ‘safe’ method of tanning is an unapproved substance, administered without medical supervision, without quality control, and often without users knowing exactly what is in the bottle,” dermatologist and researcher Simone Goldinger told ScienceAlert.
How melanotan II works
Melanotan II was developed in the 1980s as part of a University of Arizona research program aimed at achieving a tan without exposure to ultraviolet rays.
The substance mimics the action of alpha-stimulating hormone of melanocytes and stimulates the production of melanin, the pigment responsible for skin color.
Researchers later discovered that it produces other effects on the body, including male sexual function, with one of the most serious side effects reported being priapism – a painful and prolonged erection that is a medical emergency.
The biggest concern of dermatologists, however, concerns the effects on the skin.
Although some users claim that melanotan II protects against skin cancer, experts say there is no scientific evidence to support this. On the contrary, some studies have indicated a possible association between the use of the substance and the occurrence of melanoma, the most aggressive form of skin cancer, even if the link has not been definitively demonstrated.
“From the dermatologists’ point of view, the biggest concern is the effect on moles. There are reports of melanoma in people who used melanotan, which makes biological sense because the substance constantly stimulates the proliferation of pigment cells,” explained Simone Goldinger.
Specialists draw attention to the fact that melanotan II can darken existing moles and promote the appearance of new ones, which makes it difficult to detect a possible melanoma early.
A dangerous myth: tanning does not protect against cancer
Doctors also warn of another major risk: the false impression that tanned skin provides protection against ultraviolet rays.
A study published in 2025 that looked at the experiences of 29 melanotan II users found that most believed the substance protected them against skin cancer because it prevented sunburn.
Experts categorically reject this idea.
“Melanotan II does not protect the skin against the harmful effects of ultraviolet radiation. This is a very widespread myth. People think that tanning protects them from sunburn or skin cancer, but this is not true. Using sunscreen remains essential.” Goldinger pointed out.
According to dermatologists, the growing popularity of melanotan II on social media highlights the lack of effective regulations on the promotion of such products and the risk that users will be influenced by content that minimizes or completely ignores adverse effects.
