Modern Thyroid Clinic grew from McCall McPherson’s thyroid care struggle

Modern Thyroid Clinic, a self-funded telehealth practice based in Bee Cave, Texas, grew out of founder McCall McPherson’s own fight to get treatment for thyroid symptoms, according to Fortune. The company now operates in 48 states and expects lower-mid eight figures in revenue this year, McPherson told the outlet.

McPherson, a physician assistant and the company’s CEO, told Fortune she was 27 and working in medicine while spending about 16 hours a day in bed. She said she had gained weight, was losing hair, felt depressed and struggled with mental clarity while taking levothyroxine, the thyroid drug widely used by U.S. patients.

After asking her doctor to adjust her treatment, McPherson said he ran one lab test, told her the thyroid was fine, suggested diet and exercise, and considered lowering her dose. She told Fortune that the appointment became the starting point for the clinic she later built.

What is Modern Thyroid Clinic?

Modern Thyroid Clinic is a telehealth practice focused on thyroid care. Fortune reported that McPherson started it as a very small operation in which she handled clinical work, scheduling and medical assistant duties, while paying one person $2 for each answered call.

The company now employs close to 40 people, according to McPherson. Fortune reported that it appeared on the Inc. 5000 in 2025 and 2026, and that McPherson was included on Inc.’s Female Founders 500 list in 2025.

The business has grown in a field with broad demand, especially among women. The American Thyroid Association estimates that 20 million Americans have some form of thyroid disease, that one in eight women develops a thyroid disorder during her life, and that women are five to eight times more likely than men to receive a thyroid diagnosis.

How does Modern Thyroid Clinic treat thyroid disease?

McPherson’s model challenges standard thyroid care, according to Fortune. She argues that relying mainly on one lab value and levothyroxine, a synthetic form of the inactive T4 hormone, can miss patients who do not convert T4 efficiently into the active T3 hormone.

Fortune reported that Modern Thyroid Clinic uses a broader lab panel than a typical primary-care visit and prescribes active thyroid hormone rather than T4 alone. The clinic also treats Hashimoto’s, an autoimmune disease linked to most hypothyroidism, as a condition that can be managed down rather than only watched, according to McPherson’s approach.

McPherson told Fortune that her own symptoms improved after she waited months to see a physician who ran additional labs and prescribed active thyroid hormone. She said that doctor became a mentor, and that she began studying thyroid research while working in integrative and functional psychiatry.

She told Fortune that more patients with treatment-resistant depression later came to her and were found to have thyroid conditions. Patient praise spread through thyroid advocacy platforms, and McPherson said thyroid patients eventually made up about 90% of her new psychiatry patients even before she marketed herself that way.

The clinic also hires only women who have thyroid conditions themselves, Fortune reported. McPherson told the outlet that patients often arrive after seeing multiple providers and may feel more believed by clinicians with similar experiences.

McPherson has written a book, Take Back Your Thyroid, scheduled for release by Penguin Random House in February 2027, according to Fortune. She told the outlet that she wants the clinic’s approach to become standard care.

This story draws on original reporting from Fortune.