By Emily Marson, L.Ac. | Aphrodite Fertility Acupuncture, San Diego

A specific set of gut bacteria helps decide how much estrogen stays active in your body. This community is called the estrobolome, and it works through an enzyme called beta-glucuronidase. When that enzyme runs too hot or too cold, estrogen levels drift out of balance, and estrogen balance sits underneath ovulation, endometriosis, and PCOS (now PMOS). The science is real and fast-moving. The commercial “fix your estrobolome” products are ahead of it. Here is the honest line between the two.

What is the estrobolome?

The estrobolome is the collection of gut bacterial genes capable of metabolizing estrogen. Think of it as the microbiome’s estrogen department. The key player is a bacterial enzyme called beta-glucuronidase, encoded by the GUS gene in gut microbes (review on gut microbial beta-glucuronidase, 2023).

Your ovaries, adrenal glands, and fat tissue make estrogen. Your liver then packages used estrogen for disposal by attaching a molecule to it, a process called conjugation. Conjugated estrogen is inactive and headed for the exit through the gut. That is where the estrobolome intervenes.

The recycling switch

Bacterial beta-glucuronidase snips that disposal tag back off. The freed estrogen becomes active again and gets reabsorbed into circulation instead of leaving the body. Researchers call this loop enterohepatic recycling. In plain terms, your gut bacteria decide how much estrogen you send out versus how much you reclaim.

• Balanced beta-glucuronidase: a healthy amount of estrogen is recycled, and levels stay in range.
• Overactive beta-glucuronidase: too much estrogen is reactivated and reabsorbed, so more stays in circulation. This state is linked to estrogen-driven conditions.
• Underactive: the opposite, where more estrogen is cleared, which can leave levels low.

How could gut bacteria affect fertility?

Estrogen is not a background hormone in reproduction. It builds the uterine lining, it drives the follicle toward ovulation, and its balance with progesterone shapes the whole cycle. If the estrobolome tips estrogen too high or too low, the downstream effects show up in exactly the conditions fertility patients deal with.

Where the research points

• Endometriosis. Endometriosis is estrogen-dependent. A dysbiotic gut with overactive beta-glucuronidase can push more estrogen back into circulation, and elevated circulating estrogen is associated with endometriosis progression (Gut Microbes, 2023).
• PCOS and PMOS. Altered estrogen metabolism is one thread in the tangle of PCOS (now PMOS), which also involves insulin and androgens. Gut dysbiosis shows up repeatedly in this population.
• Cycle regularity. Estrogen that runs too high relative to progesterone can disrupt the timing of ovulation and the quality of the luteal phase.

Read that carefully. These are associations and plausible mechanisms, not a proven chain where fixing your gut fixes your fertility. The estrobolome is a contributor to estrogen balance, one of several, and estrogen balance is one input into fertility, one of many.

Can you actually change your estrobolome?

This is where the marketing gets ahead of the evidence, so slow down before you spend.

What has reasonable support

• Fiber. A diverse, plant-heavy diet feeds a more diverse microbiome, and diversity is associated with more balanced beta-glucuronidase activity. This is the least glamorous and best-supported lever.
• Overall gut diversity. Fermented foods and a wide range of plants support the broad microbial community the estrobolome lives within.
• Reducing what disrupts the gut. Repeated courses of antibiotics, heavy alcohol, and long stretches of ultra-processed eating all shift the microbiome, and some medications alter beta-glucuronidase activity directly (estrobolome and long-term medication, 2026).

What is promising

• DIM. The liver filters estrogen from the blood and converts it into metabolites. DIM helps shift this process toward “good” estrogen metabolites (2 -hydroxy estrogens) and away from “bad” metabolites (16 -hydroxy estrogens). Once processed by the liver, the deactivated estrogen travels into the gut to be eliminated via bowel movements. Targeting the upstream processing of estrogen via the liver can help the overall processing of estrogens out of the body. 
• Beta-glucuronidase. Calcium-d-glucarate and similar compounds are sold to lower beta-glucuronidase.  This is an interesting hypothesis, not a proven treatment.
• At-home estrobolome tests. They can profile your gut bacteria. They cannot yet tell you a specific action that will change your fertility outcome.

How we think about the gut and fertility at Aphrodite

What the estrobolome research reinforces is unglamorous and real: the gut is part of how your body regulates hormones, and the same habits that support a diverse microbiome (fiber, plants, fewer disruptors, lower chronic stress) also support the estrogen balance a healthy cycle depends on. In clinic, we treat the whole picture: blood flow, stress physiology, and the lifestyle inputs that feed the gut. We stay specific about what is proven versus what is a promising lead.

Frequently asked questions

What is the estrobolome in simple terms?
It is the set of gut bacteria and their genes that process estrogen. Through an enzyme called beta-glucuronidase, they help decide how much estrogen your body recycles back into circulation versus clears out.

Can gut bacteria really affect estrogen levels?
Yes. Bacterial beta-glucuronidase reactivates estrogen that the liver had tagged for disposal, allowing it to be reabsorbed. When this enzyme is overactive, more estrogen stays in circulation, which is linked to estrogen-driven conditions like endometriosis.

Does the estrobolome affect fertility?
Indirectly. It influences estrogen balance, which shapes the uterine lining, ovulation, and the cycle. The links to endometriosis and PCOS or PMOS are supported by research, though a direct chain from gut to pregnancy is not proven.

How do I improve my estrobolome?
The best-supported steps are a diverse, fiber-rich, plant-heavy diet, fermented foods, and limiting disruptors like unnecessary antibiotics and heavy alcohol. 

Should I get an estrobolome test?
For most people, no. These tests can profile your gut bacteria but cannot yet point to a specific action that reliably changes your fertility outcome. Basic gut-supportive habits give you most of the benefit without the cost.

Ready to find your answers?

If estrogen balance, endometriosis, or PCOS (now PMOS) is part of your fertility picture and you want guidance grounded in evidence rather than supplement hype, book online at aphrodite.janeapp.com or call 858.333.7688. You can also read our guides on endometriosis and getting pregnant and PCOS, now PMOS, and natural conception.

Emily Marson, L.Ac., is the founder of Aphrodite Fertility Acupuncture in San Diego. Over more than eight years she has helped 1,000+ San Diego women conceive, working alongside every major fertility clinic in the city and providing on-site acupuncture for embryo transfer. Located at 2970 Fifth Ave, Suite 320, San Diego, CA 92103.