Mind the Gap: GABA, Hormones, and the Female Gut-Brain Connection

Author: Maya Danovitch

How do hormones fluctuate across a woman’s life, and how do those fluctuations impact neurotransmitters? When life changes disrupt or decrease key neurotransmitter levels - how might we add them back?

Recently, our lead scientist Dr. Azure Grant delivered a LinkedIn Live presentation with Dr. Noah Zimmerman from Verb Biotics, a research-driven company developing probiotics. The two explored the interplay between hormones, the gut microbiome, and neurotransmission from puberty to menopause. Zimmerman noted, “we quickly realized that when we were dealing with People Science and, and with Azure in particular, they were invested in the science that we were doing.”

Here’s what we learned, the ideas we’re still exploring, and why this matters for you.

The Female Life Cycle: Hormones, Health, and Beyond

Puberty is a sensitive developmental window initiating lifelong cyclic fluctuations in estrogen and progesterone. Disrupting these cycles while they develop can create long-term changes to neurotransmitter levels in the brain.

The Menstrual Cycle doesn’t only create cycles in reproductive hormones and function - it creates monthly cycles in the levels of and sensitivity to neurotransmitters like serotonin, dopamine, and GABA.

Pregnancy increases key hormone levels to lifetime highs, profoundly affecting brain chemistry and gut function.

Perimenopause and Menopause are marked by destabilization and decline estrogen , progesterone and neurotransmitter levels, alongside sleep disturbances, mood swings, and GI issues.

Insight: These fluctuations are rooted in real, measurable shifts in brain and gut chemistry, and understanding them is key to supporting women’s health at every age.

Estrogen and the Gut Microbiome: The Missing Link?

Not only does estrogen regulate reproduction, it also helps maintain the gut barrier, reducing inflammation and supporting healthy neurotransmitter production. As estrogen declines (with age or menopause), gut permeability increases, inflammation rises, and the “estrobolome” (estrogen-regulating bacteria) diminishes. This can amplify hormonal symptoms and affect mental health.

Insight: Supporting gut health—through diet, lifestyle, and potentially probiotics—may be a powerful way to ease hormonal transitions and support mood, sleep, and overall well-being.

Replenish a Neurotransmitter with a Probiotic? A New Frontier for Mood and Sleep

GABA is the brain’s main “calming” neurotransmitter, crucial for sleep and stress resilience. As Grant explained, hormonal instability and decline can disrupt concentration and/or expression of GABA, especially in perimenopause and menopause. This can contribute to anxiety, irritability, and insomnia. Hormonal replacement, via patches, injections or cyclic application of creams to mimic the menstrual cycle, are used by millions of women to ease symptoms of menopause. Might a novel approach to replacement of declining neurotransmitter levels support healthy aging as well?

People Science and Verb Biotics are exploring new ways to replenish GABA naturally, including sustained-release, GABA-producing probiotics. Early clinical trials show promise for improving sleep and reducing stress within weeks: “by the second day of taking this probiotic, we started to see release [of GABA]. And then by the end of the week, it was statistically significant,” Zimmerman shared. Recent RCT results of collaboration between Verb Biotics and People Science are published in Beneficial Microbes and In Review.

Insight: This approach could offer a gentler, more sustainable alternative to pharmaceuticals, harnessing the gut-brain axis to support mental health.

What’s Next? Questions We’re Still Exploring

• How can we optimize hormone and neurotransmitter replacement—timing, dosing, and delivery—for women at different life stages?

• How do dietary phytoestrogens (like soy) and herbal remedies fit into the bigger picture?

• What are the long-term effects of GABA-producing probiotics on the microbiome and mental health?