The TGA is urging people keen on tanning to steer clear of a so-called image-enhancing substance dubbed the ‘Barbie’ drug.

The watchdog is warning that the unlicensed agents Melanotan-I and Melanotan-II — sold online for as little as $80 a vial — can cause kidney failure, impaired liver function and rhabdomyolysis.

As the drug has a short half-life, a user needs to inject it every second day to maintain the artificial tan it produces in the skin.

“Side-effects include darkened skin, increased moles and freckles, nausea, vomiting, loss of appetite, flushing of the face, involuntary stretching and yawning, and spontaneous erections,” the drug regulator notes.