When ovarian estrogen falls in menopause, the vaginal lining thins and makes less glycogen (the sugar that feeds protective Lactobacillus bacteria). Without that food source, Lactobacillus often declines and the vaginal bacterial community becomes more diverse — which raises vaginal pH and weakens the natural acidic barrier.

Those tissue and microbiome changes are closely linked to the symptoms many people experience and call genitourinary syndrome of menopause (GSM): vaginal dryness, burning, pain with intercourse, and more frequent yeast or bacterial infections. In other words, these problems aren’t just “normal aging” — they reflect measurable shifts in local biology.

Applying estrogen locally inside the vagina (vaginal or local estrogen) reliably improves tissue health, restores glycogen production, lowers pH, and often brings back Lactobacillus dominance — with clear symptom relief for many women. Non-hormonal options (moisturizers, lubricants, pH-balancing products, and some probiotic approaches) can ease symptoms and are useful when hormones aren’t appropriate, but the evidence that they consistently rebuild a protective microbiome is weaker and more mixed.

Key takeaways

• Estrogen → glycogen → Lactobacillus → low pH = healthy vaginal ecosystem; menopause interrupts that chain.
• GSM symptoms (dryness, pain, infections) are linked to these microbiome and tissue changes — they are treatable, not inevitable.
• Vaginal (local) estrogen is the most consistently supported therapy to restore both tissue and a Lactobacillus-friendly microbiome; non-hormonal fixes help comfort but have less consistent microbiome data.

View the study here: https://www.sciencedirect.com/science/article/abs/pii/S0378512216301244