There are no formal scientific studies of whether or not urine is effective for cleaning or hair regrowth, according to National Geographic. Additionally, there is no scientific evidence to prove whether or not there are health risks associated with rinsing hair with urine.
Anecdotal reports of urine increasing hair growth are common on the Internet, notes National Geographic. However, there is no scientific evidence to support these claims. Additionally, while proponents of using urine as a hair and skin cleaner claim it can wash dirt and oils away from the skin, National Geographic points out that soap and water are already effective cleaners, and the efficacy of urine as a cleaner has not been scientifically proven.
The health risks for using urine for medicinal purposes are too high in relation to the potential benefits, cautions National Geographic. For example, drinking urine daily to improve health may actually be harmful to health. Additionally, the urban legend that putting urine in the eye can treat eye infections has resulted in even worse health problems. Putting urine in an eye can result in the transmission of STDs such as chlamydia or gonorrhea into the eye, resulting in a much worse infection than the initial one.