Pregnenolone — The Master Neurosteroid
Pregnenolone is the first steroid synthesised from cholesterol and the precursor to all other steroid hormones (progesterone, DHEA, cortisol, testosterone, estrogen, aldosterone). It is also a potent neurosteroid with direct effects on memory, mood, and neuroprotection. Pregnenolone levels decline ~60% between ages 35 and 75.
Mechanism of Action
Pregnenolone modulates GABA-A receptors (reducing anxiety), NMDA receptors (enhancing memory), and sigma-1 receptors (neuroprotection). It promotes myelination of neurons and has anti-inflammatory effects via NF-κB inhibition. As the precursor to DHEA and downstream hormones, it can replenish the entire steroid hormone cascade.
Human Trial Evidence
A 1994 Psychoneuroendocrinology study showed pregnenolone is the most potent memory-enhancing steroid in rodents. Human trials are limited — a 2010 Neuropsychopharmacology RCT showed 500 mg/day pregnenolone improved working memory in schizophrenia patients. Observational data links higher pregnenolone levels to better cognitive function in older adults.
Dosing Protocol
10–50 mg/day. Best taken in the morning with food. Start low (10 mg) and titrate. Monitor downstream hormones (DHEA-S, testosterone, estradiol, cortisol) with long-term use. Micronised forms have better bioavailability. Often used cyclically (5 days on, 2 days off).
Safety & Contraindications
Requires monitoring. Can convert to DHEA, testosterone, or estrogen — may cause androgenic or estrogenic side effects. Contraindicated in hormone-sensitive cancers. May cause anxiety, insomnia, or irritability at high doses (stimulating). Avoid in pregnancy. Requires physician supervision.