Research has found that the hormone melatonin is affected by this seasonal change.

The hormone melatonin - only released during darkness - seems to be at the heart of it all.

Onset of sleep was linked to a spike in the hormone melatonin.

They also seem to affect how much of the hormone melatonin your body makes at night.

Some studies have pointed to the hormone melatonin, which is regulated by circadian rhythms, as a possible mechanism.

Those clocks, he said, tend to have a common pendulum: the hormone melatonin.

Using alternative medicine, such as valerian root or the hormone melatonin.

Two other ways to handle this situation are bright light therapy and use of the hormone melatonin.

The hormone melatonin is said to help people sleep.

Dr. Lerner is perhaps best known for leading the team of researchers who isolated and named, in 1958, the hormone melatonin.