Suntan Addiction Explained

Even though researchers established a strong link between sunlight and skin cancer long ago, the number of patients diagnosed with melanoma continues to steadily increase, according to the National Cancer Institute. People fervently seek ultraviolet rays on the beach and in the tanning salon despite the trend, so scientists suspect sunlight might be addictive. And they think β-endorphin, an opioid peptide produced in the skin by UV light, could be to blame. A research team led by David E. Fisher of Massachusetts General Hospital and Harvard Medical School has confirmed those suspicions with an extensive study on mice (Cell 2014, DOI: 10.1016/j.cell.2014.04.032). After dosing mice with UV light for weeks, the researchers observed the rodents’ β-endorphin levels increase. When given naloxone, a drug that blocks the opioid receptors to which β-endorphin binds, the mice exhibited signs of withdrawal. The researchers also studied mice that were genetically engineered to lack β-endorphin. These animals didn’t display any addiction-like behaviors when dosed with UV light. Steven R. Feldman, a dermatologist at Wake Forest University who was not involved in the research, says, “If the nail wasn’t already in the coffin that tanning is an addictive phenomenon, that final nail has been placed with this outstanding research study.”