The most frequent symptom of menopause and perimenopause is hot flushes, also known as hot flashes. They occur when the blood vessels near you skin's surface dilate to cool, but science still don't know the cause of the dilation.

That hasn't stopped scientists from inventing a way to beat them, however.

Researchers at Imperial College London have developed a drug that can cut the number of hot flushes by nearly 75 percent. The drug targets receptors in the brain and is designed for women for whom hormone replacement therapy (HRT) is either unsuitable or not preferred.

HRT is typically the most effective treatment for hot flushes, but it has issues. For one, it can increase the relative risk of breast cancer and increase the risk of blood clots.

"A lot of women are choosing not to take HRT because it is estrogen-based. This new drug is a pill which blocks the NK3 receptor, so it won't have the side-effects associated with estrogen," said Professor Waljit Dhillo, an NIHR Research Professor from the Department of Medicine at ICL.

The researchers at ICL staged a randomized, double-blind, placebo-controlled trial, recruiting menopausal women aged between 40 and 62 years old who had experienced seven or more hot flushes a day and had not had a period in at least 12 months. The women were randomly selected to either first receive a 80 milligram daily dose of the new drug or a placebo over the course of a four week period, before switching to receive the other tablet for an additional month.

The scientists learned that the new drug not only significantly reduced the average total number and severity of flushes during the four-week treatment period, it also helped to reduce the impact of flushes on the women's lives, improving sleep.

"Despite the fact that for millions of women their menopausal symptoms are intolerable so many are suffering in silence because it is a taboo subject and treatment options are limited,” said Dr Julia Prague, first author of the study. “It was so exciting to see the lives of those who participated in the study become transformed when their flushes improved once taking the new drug. They could sleep through the night, and be less embarrassed in the daytime; they told me they felt 'human again'."

The research was presented at the 2017 annual meeting of the Endocrine Society.