The study was conducted on shaved mice

It is an established fact that there is a strong link between UV exposure and different forms of skin cancer, and while 20-30 minutes of sun exposure at a time revealed no sunburn in laboratory mice, prolonged and regular exposure can have devastating effects. One week after the lab animals were first exposed to the UV rays, the scientists tested their beta-endorphin levels, which had skyrocketed such that they were enough to effectively treat pain in the mice.

The study was conducted on shaved mice that were constantly exposed to UV rays for five days a week, six weeks in a row. The shaved mice were the equivalent of fair-skinned people, and the researchers kept track of the mice’s endorphin levels on a weekly basis. It came as no surprise to see that the ‘feel-good hormone’ levels increased after just one week of sun exposure, and the endorphins basically activated the opioid receptors in the body the same way that morphine or prescription painkillers do.