On Oct. 13, 2025, researchers from Texas A&M University announced they have identified two estrogens, estradiol and estriol, that may help protect the myelin sheath, the protective nerve coating often compromised in multiple sclerosis.

About 100,000 of the estimated million people in the United States with multiple sclerosis (MS) have a progressive form of the disease, with symptoms that worsen continuously or after periods of remission.

MS is believed to occur when the immune system attacks the myelin sheath — the protective coating of the nerve fibers that transmit electrical impulses throughout the body — and disrupt this communication. The disease occurs more often in women, older people and those in northern latitudes.

Symptoms include fatigue, numbness or tingling, bladder and bowel problems and cognitive issues, but difficulty walking and balancing are the most common symptoms — and these are more pronounced in the progressive form of the disease. In addition, the progressive form is more prevalent among Black patients.

For their study, published in the Journal of Neuroimmunology, the team evaluated estriol and estradiol as possible treatment protocols through a study that used a virus to mimic progressive MS.

Estrogen is a group of hormones that primarily affect sex drive and reproductive development, especially for women. Estradiol is more potent than estriol and is used for hormone replacement therapy in postmenopausal women. Estriol, on the other hand, is used off-label for a variety of conditions and is FDA-approved only for treating urinary incontinence in dogs.

The researchers found that both types of estrogen decreased inflammation in the spinal cord, but only estradiol significantly decreased the damage to the myelin sheath, and believe this could aid in the development of therapeutic interventions for people with progressive MS.