Do Weight Loss Medications Like Wegovy and Zepbound Cause Hair Loss?
Hair loss is one of the most common concerns I hear from patients taking GLP-1 medications. Many patients become alarmed when they notice increased shedding after starting medications such as Wegovy or Zepbound, and naturally assume the medication itself is damaging their hair. The truth is more nuanced. Clinical trials have reported hair loss in a small percentage of patients taking GLP-1 receptor agonists and dual GIP/GLP-1 receptor agonists. In the SURMOUNT-1 trial, hair loss was reported in approximately 4-5% of patients receiving tirzepatide compared with about 1% receiving placebo, with women affected more frequently than men. In clinical trials of semaglutide for obesity, hair loss was reported in approximately 3% of patients compared with about 1% of placebo-treated participants.
However, these studies do not demonstrate that the medications directly damage the hair follicle. The current evidence suggests that the increased shedding is far more likely related to rapid weight loss, reduced caloric intake, inadequate protein consumption, and nutritional deficiencies- all well-recognized triggers for telogen effluvium, a temporary form of diffuse hair shedding.
Hair Is Made of Protein
Hair is composed primarily of keratin, a structural protein. When calorie or protein intake becomes inadequate, or the body experiences another significant physiologic stressor such as rapid weight loss, more hair follicles prematurely transition from the active growth (anagen) phase into the resting (telogen) phase—a process known as telogen effluvium. These hairs remain in the resting phase for approximately 2 to 4 months before they are naturally shed as new hairs begin to grow. This delay explains why many patients notice increased hair shedding several months after starting a successful weight-loss program rather than immediately after beginning medication.
The same nutritional deficiencies that contribute to hair loss may also lead to:
Loss of lean muscle mass
Decreased bone density over time
Fatigue
Poor exercise recovery
A slower metabolic rate
This is why successful weight loss should never focus solely on the number on the scale. The goal is to lose fat while preserving muscle, bone, and overall nutritional health.
A Comprehensive Endocrine Evaluation
When a patient presents with hair loss after starting a GLP-1 medication, it is my goal to determine why the hair loss is occurring. The evaluation begins with nutrition. I want to know how much weight has been lost, how quickly it occurred, whether adequate protein is being consumed, whether meals are being skipped because of appetite suppression, and whether overall calorie intake is meeting nutritional needs. Rapid weight loss itself is a well-established trigger for telogen effluvium, whether it occurs after GLP-1 therapy, bariatric surgery, illness, or intensive dieting.
Next, I evaluate for common nutritional deficiencies that contribute to diffuse hair loss. Depending on the clinical picture, laboratory testing may include a complete blood count, ferritin and iron studies, vitamin B12, vitamin D when clinically indicated, zinc, folate and copper when deficiency is suspected, and a comprehensive metabolic panel. Low ferritin remains one of the most common reversible causes of hair loss, particularly in premenopausal women.
Thyroid disease should also be excluded, as both hypothyroidism and hyperthyroidism can disrupt the normal hair growth cycle.
Finally, I assess for hormonal conditions that frequently contribute to hair thinning. These include PMOS, hyperandrogenism, perimenopause and menopause, elevated prolactin levels, and, in rare cases, adrenal or ovarian disorders causing excess androgen production. Many women begin GLP-1 therapy during the same years that hormonal changes naturally affect hair density, making it easy to incorrectly attribute the shedding to the medication alone.
Should You Stop Your GLP-1 Medication?
For most patients, the answer is no. Rather than discontinuing an effective therapy because of hair shedding, the better approach is to identify and correct the underlying cause. Optimizing protein intake, correcting nutritional deficiencies, preserving lean muscle through resistance exercise, and treating hormonal disorders often allows patients to continue their medication while supporting healthy hair regrowth.
The Bottom Line
Hair loss has been reported in clinical trials of Ozempic, Wegovy, Mounjaro, and Zepbound, but the available evidence suggests it is more likely a consequence of rapid weight loss and nutritional stress than a direct toxic effect of the medication itself. Hair loss is often multifactorial, and identifying the true cause is essential. A comprehensive endocrine evaluation can uncover nutritional deficiencies, thyroid disease, iron deficiency, hormonal disorders, or other treatable conditions that may be contributing to excessive shedding.
If you’re experiencing hair loss while taking a GLP-1 medication, don’t stop your treatment without first understanding why it’s happening. The right evaluation can often identify a reversible cause and help you continue your weight-loss journey safely. If you’re looking for a personalized, evidence-based approach, schedule a consultation with Dr. Mehdia Amini, and together we’ll identify the underlying cause, optimize your nutrition and hormonal health, and create a plan that supports both healthy weight loss and healthy hair growth.
