Isotretinoin is primarily used as a treatment for severe acne. The most common adverse effects are a transient worsening of acne (lasting 1–4 months), dry lips cheilitis dry and fragile skin, and an increased susceptibility to sunburn. Uncommon and rare side effects include muscle aches and pains myalgias and headaches. Isotretinoin is known to cause birth defects due to in-utero exposure because of the molecule’s close resemblance to retinoic acid, a natural vitamin A derivative which controls normal embryonic development. It is also associated with psychiatric side effects, most commonly depression but also, more rarely, psychosis and unusual behaviours Other rare side effects include hyperostosis and premature epiphyseal closure, have been reported to be persistent.