Commercial gels are commonly used by couples to overcome vaginal dryness during intercourse. At fertility clinics, gels are offered to men during semen collection and applied to medical devices to make them easier to insert into the body.

However, Kazim R. Chohan, senior author of the study and director of the Andrology Laboratory at the State University of New York Upstate Medical Center in Syracuse suggested that these lubricants are not beneficial for couples who wish to conceive, according to the repot.

The researchers analyzed the movement of sperm from 22 healthy donors in separate test tubes with five commercial gels and four common oils. The semen was exposed to each product for an hour, it said.

The commercial lubricant products tested were Pre-Seed, Johnson & Johnson’s, also known as Durex's, K-Y Tingling Jelly, K-Y Sensitive Jelly, K-Y Warming Jelly and Astroglide. The four common oils tested were mineral oils available as lubricants: canola oil, baby oil, sesame oil and mustard oil.

The results presented were surprising. All the commercial lubricants except Pre-Seed, a product specially formulated to help with conception, diminished the activity of sperm. Canola or baby oil had no negative impact on sperm while sesame oil drastically affected sperm movement.

Mustard oil showed the most astounding result. The semen mixed into a tube of mustard oil became hyperactive and stayed that way for at least an hour. Mustard oil was tested as it is known to kill bacteria -- hence it is often used as a vaginal lubricant by sex workers in Bangladesh, Reuters reported.

By Ha Ji-won, Intern reporter (jiwonha@heraldcorp.com)