About 80 percent of women experience hot flashes and night sweats during menopause and 20 percent of those will feel miserable enough to seek treatment.

Marcia Vidal was in her early 50s when she started feeling the uncomfortable effects of menopause.

"Hot flashes, loss of memory, edginess. I was very temperamental," she said. "I just couldn't sleep."

Unwilling to try hormone replacement therapy, Marcia was looking for an alternative when she heard about a soy supplement study called SPARE at the University of Miami Miller School of Medicine.

For that study 126 women were given a placebo or sugar pill to take daily.

Another group of 122 women were given 200 milligrams of soy isoflavone tablets.

After 2 years, researchers found no significant difference in bone loss or menopause symptoms except for one. More women in the soy supplement group reported hot flashes - 48 percent compared to just under 32 percent in the placebo group.

What was Marcia's experience?

"I was still going through the hot flashes. I was still having my highs and lows. Mentally I was handling it better thinking this is temporary, it will pass," she said.

There are a number of supplements on the market containing soy and claiming to reduce hot flashes and night sweats.

"Menopausal women taking or thinking of taking soy isoflavone should reconsider," said Dr. Silvina Levis, lead researcher in the SPARE study said.

Levis adds that contrary to popular belief, soy tablets do not provide any benefit to menopausal women, but they do not cause any harm either.