Pregnenolone serves as a precursor to other hormones, including dehydroepiandrosterone (DHEA) and progesterone. It has been suggested that pregnenolone's role in the body is to serve as a "mother steroid" (precursor hormone). Many effects of pregnenolone on the nervous system have been studied.
 

• Sleep and memory:

Studies indicate strong memory-enhancing effects, much more than those of other neuroactive substances. In healthy men between the ages of 20 and 30, administration of pregnenolone (1 mg per day) has been shown to improve sleep quality and decrease intermittent wakefulness. Pregnenolone has also been shown to develop short-term and long-term working memory and can lead to increased motivation to learn new information and an improvement in the ability to acquire new knowledge.
 

• Stress:

It has been suggested that this hormone may play a role in the neuroendocrine response to stress. In a study of stressed airline pilots, administration of pregnenolone (25 mg twice daily) improved performance without causing adverse side effects. The researchers suggested that this was a good response during a period of stress and was initiated through the nervous system.
 

• Depression:

It is known that hormones affect mood and behavior through effects on the nervous system. In people with chronic depression or a history of depression, pregnenolone in the cerebrospinal fluid (the fluid that cleans the brain) was significantly lower than the level in healthy people. In addition, it was found that patients with active depression had a lower level of pregnenolone compared to those with a history of depression.