DHEA and Pregnenolone: The Foundational Precursor Hormones
When most people think about hormone replacement therapy, they think of estrogen, progesterone, and testosterone. But two hormones that receive far less attention—DHEA (dehydroepiandrosterone) and pregnenolone—are equally important foundational pieces of the hormonal puzzle. These "precursor hormones" sit near the top of the steroidogenic cascade, converting into downstream hormones based on the body's needs. Their decline with age has far-reaching consequences that are frequently missed in standard hormonal evaluations.
The Steroidogenic Cascade
All steroid hormones are synthesized from cholesterol. The first major conversion step produces pregnenolone in the mitochondria. Pregnenolone then branches into two primary pathways: one leading to progesterone and ultimately cortisol and aldosterone (the glucocorticoid and mineralocorticoid pathways), and another leading to DHEA. DHEA, in turn, is converted to androstenedione and then to testosterone and estrogen.
This cascade means that the production of every sex hormone and stress hormone in the body depends—directly or indirectly—on adequate pregnenolone and DHEA. When these foundational hormones are deficient, the entire downstream hormonal architecture is affected.
DHEA: Functions, Decline, and Benefits of Restoration
DHEA is the most abundant steroid hormone in the circulation at its peak in the mid-20s, when levels typically range from 300–500 mcg/dL in adults. By age 70, DHEA-S (the sulfated storage form, which is what labs measure) has fallen by 80–90% from its peak—making age-related DHEA decline one of the most dramatic endocrine changes in human physiology. Yet it receives minimal attention in standard medical practice.
Precursor role: DHEA serves as the primary substrate for peripheral sex hormone production. In postmenopausal women, DHEA-derived conversion in peripheral tissues is the primary source of both estrogen and testosterone. Inadequate DHEA limits the body's capacity to maintain these downstream hormones.
Immune function: DHEA has direct immunomodulatory effects, supporting natural killer cell activity, T-helper cell function, and interleukin-2 production. DHEA deficiency is associated with reduced immune competence and increased susceptibility to infections and autoimmune dysregulation.
Insulin sensitivity: Multiple clinical studies have shown that DHEA supplementation reduces visceral fat, improves insulin sensitivity, and lowers fasting insulin in older adults. A randomized trial by Villareal and Holloszy showed that 50 mg/day of DHEA for six months significantly reduced visceral and subcutaneous fat and improved insulin action in older men and women.
Bone density: DHEA supports bone density through both its conversion to sex hormones and its direct effects on osteoblast activity. Several studies have shown that DHEA supplementation improves bone mineral density in older women, particularly when combined with calcium, vitamin D, and resistance training.
Mood and cognition: DHEA and DHEA-S are neuroactive steroids that modulate GABA, NMDA, and sigma-1 receptor activity in the brain. Multiple clinical trials have demonstrated that DHEA supplementation improves mood, reduces depressive symptoms, enhances cognitive function, and improves sense of wellbeing in adults with low DHEA levels.
Libido: In women, DHEA supplementation—both oral and intravaginal—has been shown to improve sexual desire, arousal, lubrication, and satisfaction. The FDA-approved product Intrarosa (prasterone, intravaginal DHEA) is specifically indicated for pain with intercourse in menopausal women.
Pregnenolone: The "Mother Hormone"
Pregnenolone is sometimes called the "mother hormone" because it is the biosynthetic precursor to all steroid hormones. Like DHEA, it declines significantly with age—by approximately 60% between the ages of 35 and 75. While less research exists specifically on pregnenolone supplementation compared to DHEA, the available evidence and its foundational metabolic role make it an important consideration in comprehensive hormonal care.
Neurosteroid activity: Pregnenolone is a potent neurosteroid, particularly abundant in the brain, where it modulates NMDA glutamate receptors, GABA-A receptors, and microtubule dynamics. It has been associated with improved memory formation, enhanced learning, and neuroprotection in animal studies. Clinical studies in humans have shown associations between pregnenolone levels and working memory performance.
Mood regulation: Pregnenolone acts at sigma-1 receptors to produce antidepressant and anxiolytic effects. Small clinical trials have shown benefit of pregnenolone in bipolar depression and other mood disorders.
Anti-inflammatory effects: Pregnenolone modulates inflammatory cytokine production and reduces excessive inflammatory signaling—a mechanism that may contribute to its neuroprotective and joint-protective effects.
Precursor support: For patients whose downstream hormone deficiencies appear to involve suboptimal precursor supply—rather than or in addition to glandular dysfunction—pregnenolone supplementation helps support the entire steroidogenic cascade.
Testing DHEA and Pregnenolone
DHEA-S is the standard test for DHEA status and is measured by a simple serum test. Optimal levels in adults are generally considered to be in the upper third of the reference range for the patient's age—not simply "within range" for their decade, which accepts dramatic age-related declines as normal. Pregnenolone is typically measured as a serum level, with optimal values generally in the 100–230 ng/dL range (though reference ranges vary by laboratory).
Supplementation Considerations
DHEA and pregnenolone supplementation should be guided by laboratory testing and physician oversight. Unsupervised use can lead to excessive conversion to androgens (causing androgenic side effects in women) or estrogens (causing estrogenic effects in both sexes). In the context of a comprehensive BHRT program with appropriate monitoring, supplementation to restore levels to the upper physiological range—not supraphysiological—is generally safe and well-tolerated.
Dr. Kenton Bruice, MD, includes DHEA-S and pregnenolone in his comprehensive hormone panels and addresses deficiencies as part of his individualized BHRT programs at clinics in Denver, Aspen, and St. Louis. Schedule a consultation to have your full precursor hormone status evaluated.