Estrobolome 101: How Your Gut Shapes Estrogen Balance

Ever felt like your hormones are running your life? You're not wrong, but a key player you may not know about is the estrobolome, a collection of gut bacteria that directly shapes your estrogen balance. These microbes process and recycle estrogen, influencing how much circulates in your system and how your body uses it.

When the estrobolome is off-balance, you might experience mood swings, period changes, or conditions like polycystic ovary syndrome (PCOS).

To explore this gut-hormone connection, we've teamed up with Tiny Health, a microbiome testing company that helps women understand how their gut health shapes everything from fertility to hormone balance. Here's what they want you to know about supporting your estrobolome.

What is the estrobolome?

The estrobolome is a group of gut microbes involved in estrogen metabolism. These microbes produce an enzyme called Beta-glucuronidase, which can reactivate estrogen in the gut. Once reactivated, that estrogen can be reabsorbed back into the bloodstream instead of leaving your body. It’s a regular part of estrogen recycling. But like most things, balance is key.

Certain bacteria, like Bacteroides, Escherichia coli, and Lactobacillus, produce Beta-glucuronidase [1], [2]. In a balanced gut, this recycling process runs smoothly. But when it’s disrupted, things can get off track. Too much Beta-glucuronidase activity may lead to estrogen dominance. 

Beta-glucuronidase: molecular scissors

When your liver packages up estrogen for removal, it attaches a tag that signals it’s ready to leave your body. Beta-glucuronidase can snip that tag, reactivating estrogen and allowing it to be reabsorbed.

When Beta-glucuronidase gets overactive, too much estrogen stays in circulation and can overstimulate estrogen-sensitive tissues. A recent study shows how gut bacteria reactivate these hormone compounds [3]. This reactivation process may influence breast cancer risk, especially for estrogen-dependent cancers [4], [5]. 

While Beta-glucuronidase appears to play an essential role in women's health, research on humans remains mixed. Most studies capture a snapshot in time and rarely measure how actively these enzymes are functioning. Lifestyle, diet, and genetics are also factors. 

That’s why understanding estrogen recycling, and the gut’s role in it, could help explain persistent symptoms and inform our understanding of long-term risks and prevention. With Tiny Health’s Adult Gut Health Test, you can see insights into your microbiome’s potential to produce Beta-glucuronidase, along with menopause-related markers, so you can connect symptoms to what’s happening in your gut.

Why estrogen recycling matters

We often think of estrogen in the context of monthly periods, pregnancy, and menopause. But it also impacts your metabolism, bone health, brain function, and other aspects of your overall well-being. 

When estrogen lingers in the body too long, either because it outweighs progesterone or circulates at higher-than-optimal levels, it can create estrogen dominance. In more severe cases, it may lead to conditions like PCOS, endometrial hyperplasia, and estrogen-related cancers [6], [7].  

Here’s a closer look at how heightened Beta-glucuronidase activity and estrogen recycling impact these conditions:

Polycystic ovarian syndrome (PCOS)

Polycystic ovary syndrome is usually described as an androgen-driven condition. Still, research shows women with PCOS also tend to have higher Beta-glucuronidase activity [1]. That means the gut may be playing a direct role in hormonal imbalance and insulin resistance, two key features of PCOS. The condition can cause irregular periods, acne, weight gain, and fertility issues. 

Endometrial hyperplasia

A condition where the uterine lining becomes abnormally thick, endometrial hyperplasia is linked to long-term estrogen exposure. Unlike endometriosis, which involves tissue growing outside the uterus, hyperplasia develops inside the uterus and may raise the risk of endometrial cancer. Early evidence suggests that disruptions in the estrobolome might be a factor [7].  

Breast cancer 

Breast cancer has also been linked to higher Beta-glucuronidase activity, which means disrupted estrogen recycling may actually feed estrogen-driven cancers [8], [9].  

How your gut health shapes hormone balance

When your gut microbiome is diverse and balanced, estrogen is more likely to be processed and properly cleared. But if it lacks diversity due to antibiotics, poor diet, stress, or inflammation, the estrobolome can shift in ways that increase estrogen reabsorption, potentially leading to estrogen dominance [10], [11]. 

Here's what happens: an imbalanced gut may produce too much Beta-glucuronidase, reactivating more estrogen than your body needs. At the same time, helpful bacteria that support estrogen metabolism may start to dip. 

This can show up as irregular periods, persistent bloating, mood swings, or difficulty losing weight, symptoms often blamed on hormones alone.

Imbalances create a feedback loop. Hormones affect your gut, and your gut, in turn, affects your hormones.

The estrobolome and menopause connection

Your periods may have stopped, but your gut is still actively regulating hormones. During perimenopause, typically starting in your 40s and lasting several years before your period stops, and into menopause itself, ovarian estrogen production drops dramatically. But your gut still plays a role in how much estrogen actually circulates in your body.

This becomes especially important as menopause progresses. Reduced gut microbial diversity and shifts in bacteria often lead to increased inflammation and decreased levels of beneficial short-chain fatty acids (SCFA) [12]. Meanwhile, changes in gut barrier function affect how estrogens are processed and can influence gut motility.

When estrogen recycling is disrupted, it can lead to increased estrogen exposure in specific tissues, potentially affecting your body’s fat distribution and mood. 

Your gut bacteria also produce compounds like SCFAs and tryptophan derivatives that directly affect brain function. So when your estrobolome is out of balance, you're dealing with two problems at once: disrupted estrogen processing and altered brain-supporting compounds [13].

It's a complex web of connections. How your gut handles what little estrogen remains during menopause can influence symptoms like bloating, brain fog, weight gain, mood swings, and gas. Supporting your gut during this transition may help smooth out hormonal spikes and dips. 

Estrobolome reset: 6 ways to regulate your hormones 

If you want to balance your hormones naturally, your gut is a powerful place to begin.

Whether you’re navigating PCOS, preparing for perimenopause, or simply curious, here are six ways to support your estrobolome:

1. Eat a wide variety of fiber-rich plants: Fiber supports estrogen clearance by nourishing the right gut bacteria and keeping things moving. Phytoestrogens from foods like flax and soy may help balance estrogen naturally [14].
2. Cut back on ultra-processed foods. Since fat tissue can produce estrogen, keeping your weight down may help balance your hormone levels [15]. 
3. Limit excess alcohol. Drinking too much can increase Beta-glucuronidase activity, making it harder to maintain estrogen balance [16].
4. Take antibiotics only when medically necessary. They don’t just wipe out the unfriendly bacteria. Broad-spectrum use can lower overall diversity and mess with how your body handles estrogen [17].
5. Get enough sleep and manage stress: Both impact hormone levels and gut health. Prioritizing rest, movement, and mental well-being helps keep this system in sync [18], [19].
6. Exercise regularly: Maintaining an active lifestyle helps reduce body fat, which supports hormone regulation and lowers your risk of estrogen-related conditions [20].

Start with gut insights 

While there's still so much we don't know about the gut-hormone connection, the early research is promising. Your gut plays a key role in how your body recycles and balances estrogen, so it’s not about having more or less estrogen, but about finding a healthy middle ground. 

Whether you're dealing with PCOS or navigating menopause, a healthy estrobolome supports more stable hormone signaling. Pairing hormone data with gut insights gives a fuller picture of what's driving your symptoms. Tiny Health is extending a $20 discount to the Oova community, enter code OOVA at checkout to save on an Adult Gut Health Test or a Tiny+ Membership.