Why am I losing hair? The Science of GLP-1s and Telogen Effluvium
One of the most frequent and alarming messages I receive from clients on GLP-1 therapy is that they are losing clumps of hair in the shower and wondering if the medication is toxic to their follicles.
The short answer is no. The medication itself is not poisoning your hair. However, the physiological shift your body is undergoing is significant enough to trigger a biological pause button on your hair growth.
As a researcher who has tracked these metabolic trends for over four years, I want to pull back the curtain on why this happens, and why even microdosers who are not losing much weight can still experience it.
The Research: Understanding Telogen Effluvium
In the world of clinical research, the type of hair loss seen with GLP-1s is known as telogen effluvium. Usually about 90 percent of your hair is in the anagen or growth phase. But when the body perceives a major stressor, such as a rapid shift in blood sugar, a significant caloric deficit, or a change in hormonal signaling, it enters survival mode. It decides that growing hair is non essential and shifts those follicles into the telogen or resting phase. About 3 to 4 months after that shift, those hairs fall out all at once.
Why Microdosers Lose Hair even without Weight Loss
This is the part that generic weight loss apps miss. You do not have to lose 50 pounds to experience hair loss. Even if you are microdosing for longevity or PCOS and your weight is stable, you can still see shedding.
The metabolic shock of GLP-1s changes how your body handles insulin and glucose. For a sensitive nervous system, this chemical shift is a metabolic event that can trigger telogen effluvium regardless of the number on the scale. Additionally, even at low doses, GLP-1s can slightly slow gastric emptying. If your absorption of key hair minerals like zinc, ferritin, and selenium is even slightly compromised, your follicles are the first to lose their supply. The double signaling of GIP and GLP-1 can also be a more intense message to the brain, sometimes triggering a stress response that deprioritizes hair growth.
The Advantage of Personalized Support
This is why having a specialized practitioner in your back pocket is essential. While large platforms might tell you to eat more protein, a research backed approach looks deeper. In my practice, we do not wait for the hair to fall out. We use pre loading protocols and synergistic supplementation to mitigate the side effects before they start.
We ensure your ferritin levels are optimal before you start because hair follicles are iron hungry. We focus on specific amino acids like cysteine and methionine that build the keratin bridge in your hair. Sometimes, adding a secondary peptide that supports collagen synthesis or mitochondrial health can protect the follicles from metabolic stress. We also track B vitamins and Vitamin D, which act as the co factors for hair cell division.
Will it last forever?
The most important thing to know is that telogen effluvium is temporary. Once your body feels safe again and we have corrected the nutrient gaps, the follicles will re-enter the growth phase. Having a voice to connect with means you do not have to panic or buy expensive products that do not work. We address the root cause, the internal metabolic signal, to ensure that your journey to metabolic health does not cost you your hair. We will work together on meal timings, vitamins, minerals, antioxidants, and exercise type for the best strategies to improve metabolic health.
Research References
Vidal, S. I., et al. (2026). Increased Incidence and Risk of Hair Loss with GLP-1 Receptor Agonists: A Real World Multicenter TriNetX Cohort Study. Journal of the American Academy of Dermatology International.
Jastreboff, A. M., et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, 387(3), 205, 220.
Burke, J., et al. (2025). Alopecia and Semaglutide: Connecting the Dots for Patient Safety. Journal of Clinical and Aesthetic Dermatology.
Akiska, Y. M., et al. (2025). Telogen Effluvium and Alopecia Rates in GLP-1 Receptor Agonist Users. European Academy of Dermatology and Venereology Congress.
Zhou, K. (2026). Nutritional Deficiencies and Hormonal Changes in GLP-1 Associated Hair Loss. Cleveland Clinic Health Essentials.