The Endocrine Society Jul 12 2025 People with an underactive thyroid may have an increased risk of developing small intestinal bacterial overgrowth (SIBO), a risk that may be reduced with thyroid hormone treatment, according to a study being presented Saturday at ENDO 2025, the Endocrine Society's annual meeting in San Francisco, Calif. We now know that people with hypothyroidism, especially those with autoimmune thyroiditis, are more likely to develop SIBO, but this risk appear to be mitigated