A study has shown that taking underarm sweat from a man and putting it on the lips of a woman will put her in a better mood and regulate her menstrual cycle!

Researchers created a study where they applied excretions from the underarm of a male on the upper lip of 18 women between the ages of 25 and 45. The women were unaware of what was on their upper lip. Apparently, some of them thought the study was on alcohol or perfume. 

Over a six hour period, the women rated their moods and consistently reported feeling more relaxed and less tense than those that didn't have sweat on their lips. The researchers also found that the male pheromones from the sweat also caused a shift in blood levels of the female reproductive hormone called luteinizing hormone. 

The hormone generally surges before a woman starts her menstrual cycle. Each of the 18 women were given three doses of the male sweat during the six our evaluation. It was followed by three doses of ethanol, or alcohol, over another six hour period. 

The male pheromone extract speeded up the smaller surges of the luteinizing hormone that occurs during the menstrual cycle and shortened the lulls between the surges by 20%.

(Source)