Lower DHEA-S and testosterone reduce androgen receptor signaling and worsen vaginal atrophy.

The physiological maintenance of vulvovaginal health depends on a complex interplay of sex steroids, where androgens like testosterone and its precursor DHEA-S play a critical, albeit often overlooked, role alongside estrogen. Evidence suggests that a decline in these androgens directly impacts the structural integrity and secretory function of the vaginal environment.

Clinical and effectiveness evidence

In postmenopausal populations, the age-related decline in circulating androgens is closely linked to the Genitourinary Syndrome of Menopause (GSM).

• Androgen-Specific Impact: Clinical trials involving intravaginal DHEA (prasterone) demonstrate significant improvements in vaginal dryness and dyspareunia. In a randomized controlled trial (n=482), DHEA significantly reduced vaginal pH and increased the percentage of superficial cells compared to placebo (p < 0.0001).
• Testosterone and Tissue Health: Small-scale clinical studies (n=20-40) have shown that local testosterone application can increase vaginal blood flow, epithelial thickness, and mucus production. This suggests that low testosterone levels contribute to the hallmark thinning and dryness of vaginal atrophy.
• Independent Action: Notably, androgens remain effective in improving tissue elasticity and lubrication even in patients on aromatase inhibitors, who have near-zero estrogen levels. This indicates that androgen receptor (AR) signaling provides a distinct and complementary pathway for maintaining vaginal health.

Mechanistic explanations

The vagina is an "intracrine" organ, meaning it possesses the enzymatic machinery to convert circulating precursors into active hormones locally.

• Receptor Distribution: Androgen receptors are densely distributed throughout the vaginal mucosa, lamina propria, and muscularis, as well as the vulvar tissues (clitoris and labia).
• Ligand Availability: DHEA-S and testosterone serve as the primary ligands for these receptors. When systemic levels fall, the local concentration of dihydrotestosterone (DHT) and testosterone within the tissues decreases, leading to reduced AR activation.
• Structural Maintenance: AR signaling stimulates the production of collagen and elastin fibers and maintains the health of the squamous epithelium. Without sufficient signaling, the vaginal wall loses thickness and its ability to produce moisture, leading to the clinical presentation of atrophy.

Bottom line

The claim that lower DHEA-S and testosterone reduce androgen receptor signaling and worsen vaginal atrophy is supported by science. While estrogen remains the primary hormone for vaginal health, androgen signaling is a vital independent factor for maintaining tissue structure and lubrication in postmenopausal women.