LONDON (Reuters) - A mystery chemical isolated from the sweat of young women seems to act as a romance booster for their older counterparts.

When the researchers added the compound, Pheromone 10:13, to a perfume and gave it to older women, it made their partners more affectionate.

"In diaries kept by the women for 6 weeks, 41 percent of pheromone users reported more petting, kissing and affection with partners," New Scientist magazine said Wednesday.

Pheromones are airborne chemicals secreted from the body and recognized by their smell. Humans and animals emit pheromones.

Joan Friebely of Harvard University and Susan Rako, a doctor from Newton, Massachusetts, studied the behavior of 44 post-menopausal women. Half were given a perfume with the compound while the remainder used a fragrance with a placebo or dummy chemical.

Only 14 percent of women using the perfume with the placebo reported an increase in affection from their partners.

Biologist Winnifred Cutler, the discoverer of the mystery pheromone, is keeping the identify of the compound a secret until patents have been granted to her organization, the Athena Institute for Women's Wellness Research in Chester Springs, Pennsylvania, according to the magazine.