The estrobolome is the collection of gut bacteria responsible for metabolizing estrogen, and it plays a direct role in how much active estrogen circulates through your body at any given time.
Most conversations about estrogen focus on the ovaries, or on menopause itself. Few mention the gut, even though a specific community of gut bacteria is actively involved in deciding how much estrogen your body reabsorbs versus clears out. That community is called the estrobolome, and it may explain why two women with similar hormone levels on paper can experience very different symptoms.
What the Estrobolome Does
The estrobolome is a subset of the gut microbiome made up of bacteria that carry genes for metabolizing estrogen. These bacteria produce an enzyme called beta-glucuronidase, and this enzyme is the estrobolome’s main functional tool for influencing circulating estrogen levels.
Here’s the short version of how it works. The liver processes estrogen and tags it for removal from the body, sending it into the bile to eventually be excreted. But before that happens, some of it passes through the gut, where beta-glucuronidase produced by estrobolome bacteria can remove that tag. Once the tag is removed, the estrogen is reactivated and reabsorbed back into the bloodstream instead of leaving the body, a process called enterohepatic circulation. This means the estrobolome isn’t just a passive bystander in hormone metabolism. It has a direct hand in how much estrogen recirculates in the body versus how much gets cleared.
Why Balance in the Estrobolome Matters
Like most systems in the body, this one works best in balance. A healthy, diverse estrobolome keeps beta-glucuronidase activity at a level that supports normal estrogen recycling without tipping into excess. When gut bacteria diversity drops, a state that researchers call dysbiosis, beta-glucuronidase activity can shift out of that range, and estrogen metabolism becomes less predictable as a result.
This has real, documented downstream effects. Research has connected estrobolome imbalances to a range of estrogen-related conditions, from disruptions in bone health to shifts in cardiometabolic risk. None of this means the gut is the only factor driving hormone health, but it is a meaningfully underdiscussed one.
The Estrobolome During Perimenopause and Menopause
The relationship between the estrobolome and menopause runs in both directions. Estrogen itself shapes gut microbiome diversity, and as estrogen naturally declines during the menopause transition, the composition of the gut microbiome shifts along with it. A large cohort study following women through this transition found that menopause is associated with clear, measurable changes in both the gut microbiome and the estrobolome specifically, with implications for cardiometabolic health.
This is a genuinely bidirectional relationship: declining estrogen changes the gut, and a changing gut can influence how efficiently remaining estrogen is metabolized and reused. For women already managing the broader effects of declining estrogen on collagen production in the skin, bone, and connective tissue, this adds another layer, not because the gut can replace what estrogen once provided, but because supporting it removes one more variable working against an already-strained system.
How to Support a Healthy Estrobolome
The research on estrobolome health points toward a few consistent, practical habits, not a single fix.
Prioritize fiber and fermented foods. A diet rich in fiber, along with fermented foods like yogurt and kefir, supports a more diverse gut microbiome, which in turn supports a more balanced estrobolome.
Consider probiotic support. Specific probiotic strains have been studied for their role in supporting gut bacterial diversity, which is directly tied to estrobolome function.
Limit what disrupts gut diversity. Excess sugar, excess alcohol, chronic stress, and frequent antibiotic use are all associated with reduced gut microbiome diversity, which can shift beta-glucuronidase activity out of its healthy range.
Be consistent, not aggressive. Gut microbiome composition shifts gradually in response to sustained habits, not short-term fixes, which is part of why steady, daily choices matter more than occasional resets.
The Estrobolome and Your Estrogen-Collagen Connection
At Monna, we think about hormone health as one connected system, not a collection of separate symptoms. The estrobolome makes that case concretely: it directly regulates how much estrogen recirculates through our body, and that circulating estrogen is the same hormone binding to receptors on the fibroblasts, osteoblasts, and connective tissue cells responsible for collagen production throughout skin, bone, joint, and connective tissue. A disrupted estrobolome doesn't just affect digestion or general wellness in the abstract. Research has already tied estrobolome shifts during menopause to measurable changes in cardiometabolic risk, and the same enterohepatic circulation that recycles estrogen for those outcomes is recycling the estrogen your collagen-building cells depend on.
This is why gut health and structural health aren't separate conversations, even though they're rarely discussed together. Supporting the estrobolome, through fiber, fermented foods, and the other healthy habits above won't replace what declining ovarian estrogen production takes away during perimenopause and menopause. But a well-functioning estrobolome means more of the estrogen your body does produce actually gets used rather than lost to inefficient metabolism, which makes it one more lever, alongside targeted collagen support, in maintaining the hormonal signal collagen-dependent tissue relies on.
1 Gut microbial beta-glucuronidase: a vital regulator in female estrogen metabolism. Gut Microbes. pmc.ncbi.nlm.nih.gov/articles/PMC10416750.
