Women suffering from pre-menstrual syndrome may soon get instant relief from a nasal spray.

The spray contains a mix of pheromones, the airborne chemical messengers best known for their role in animal mating behaviour.

The makers claim it will free women from the irritability, depression and other symptoms of pre-menstrual syndrome (PMS) and the more severe pre-menstrual dysphoric disorder (PMDD).

New Scientist magazine reports that early tests on 20 women show that the spray eased both mood disorders and physical symptoms like breast pain.

PMS affects up to two out of five women of childbearing age.

Prozac

Many researchers now think the condition is sparked by fluctuating hormones affecting brain activity.

As a treatment doctors often prescribe mood-altering drugs such as Prozac, which works by elevating serotonin levels in the brain.

Doctor David Berliner is one of the founders of the company developing the spray, Pherin Pharmaceuticals of Mountain View, California.

He said human pheromones were powerful mediators of sexual attraction, anxiety and hormone-related disorders.

For years, few researchers believed human pheromones existed, but over the past decade Dr Berliner and others have shown that these chemicals, exuded from human skin, can induce calmness in the opposite sex.

The chemicals are detected by a specialised organ in the nose, called the vomeronasal organ or VNO.

Artificial compound

To target pre-menstrual syndrome, Dr Pherin has developed a pheromone-like compound or "vomeropherin" known as PH80.

With each inhalation, PH80 binds to receptors in the VNO.

Nerve cells then speed the message to the hypothalamus, the part of the brain dedicated to maintaining the body's chemical balance which regulates sexual drive, anxiety, fear and appetite among other traits.

Because the vomeropherin has a direct line to the brain, relief is immediate.

Dr Berliner said the effect lasted for between two and four hours.

Pherin is now setting up full clinical trials of the spray.

Dr Bruce Kessel, a specialist in PMS at the University of Hawaii, said: "It's an intriguing and novel approach."

Dr Berliner's team is now developing different vomeropherins which they hope will target particular behaviours.