Bioavailable, micronized form. Produced by the body's adrenal glands, pregnenolone is a direct precursor of both DHEA and progesterone. Pregnenolone is the building block for all other steroid hormones. Pregnenolone levels drop dramatically after age 30. Research indicates that restoration of pregnenolone to the levels of healthy young adults may have positive effect on memory, mood, and energy.