The Endometriosis and IBS connection
The one common factor with all of my endometriosis clients - gut issues.
Many women with endo have been told that they have Irritable Bowel Syndrome (IBS) - this is because endo and gut health are connected, and the state of your gut can actually worsen endo symptoms and endo progression.
Many people with endometriosis experience symptoms that overlap with gut issues, particularly bloating (often referred to as “endo belly”) and digestive discomfort that resembles IBS. This can include abdominal pain, pain during bowel movements, nausea, and indigestion.
Because these symptoms are so similar, endometriosis is sometimes mistaken for common gastrointestinal conditions like IBS or food intolerances. This overlap can make diagnosis more difficult and may delay appropriate treatment and support.
Here are some important factors connecting gut health to endo:
Intestinal Permeability / Leaky Gut
Chronic inflammation, stress, poor diet, or gut infections can all weaken the lining of the gut - creating small gaps that allow inflammatory compounds, toxins, or bacteria to “leak” into the bloodstream. This can trigger immune activation, systemic inflammation, and even worsen endo symptoms.
Research suggests women with endometriosis often show signs of increased intestinal permeability, which may contribute to flares, pain, and fatigue.
Gut Bacteria & Endotoxins (LPS)
Certain gut microbes can produce inflammatory molecules called lipopolysaccharides (LPS) endotoxins. When LPS enters circulation through a leaky gut, it can activate and aggravate the immune system and promote the growth of endometriosis lesions. This is why doing a gut microbiome test and identifying these microbes and the level of LPS being produced is essential in addressing your endo.
Beta-glucuronidase enzyme
Another important gut-endometriosis connection involves an enzyme called beta-glucuronidase. This enzyme is produced by certain gut bacteria in the colon and is responsible for oestrogen (and toxin) reabsorption in the colon. When beta-glucuronidase levels are too high, it can lead to oestrogen being reabsorbed back into the bloodstream instead of being excreted through stool - contributing to higher overall oestrogen levels in the body. Since oestrogen can fuel endometriosis lesion growth and inflammation, an imbalanced gut microbiome with elevated beta-glucuronidase activity may make symptoms worse.
Low Beneficial Bacteria & Butyrate
The gut microbiome should be rich in diverse, beneficial bacteria - but many women with endo have low levels of these beneficial microbes, especially those that produce anti-inflammatory short-chain fatty acids (SCFAs) like butyrate.
Butyrate is a key anti-inflammatory compound that supports gut lining repair, (reduces leaky gut) and immune regulation. Without enough butyrate-producing bacteria, higher inflammation levels can occur - worsening endo.
Butyrate and beneficial gut microbes play a key role in the gut-brain axis, helping to support mood, mental clarity, and emotional resilience. Since many women with endometriosis experience low mood and anxiety, nurturing the gut is an often-overlooked but essential part of the endo healing puzzle
SIBO (Small Intestinal Bacterial Overgrowth)
Women with endometriosis are more likely to experience SIBO - a condition where bacteria overgrow in the small intestine, leading to bloating, food sensitivities (especially to high FODMAP foods), abdominal pain, and altered motility (constipation and/or diarrhoea). SIBO can further impair digestion, nutrient absorption and drive inflammation, contributing to worsening endo symptoms.
SIBO is now known to make up 80% of IBS diagnoses, after all - IBS is a “syndrome” meaning a cluster of symptoms with no known cause. One study found that 91.9% of women with endo also had SIBO (PMID: 39959963).
What now?
If you have endometriosis and also suffer from IBS, it is time you investigated what is actually going on in your gut. Understanding the link between endometriosis and IBS is essential in managing and improving endometriosis symptoms (some people even go into endo remission) and improving quality of life
For all of my endometriosis clients, I do SIBO breath testing, gut microbiome testing (Cobiome lab) and vaginal microbiome testing (Juno Bio) to really understand their whole inflammatory picture and figure out what their specific endo drivers are.