Does Mounjaro cause hair loss?

Key Points

• Mounjaro (tirzepatide) doesn't directly cause hair loss, but the rapid weight loss it facilitates is a well-known trigger for temporary hair shedding.
• Significant calorie restriction during weight loss can lead to deficiencies in nutrients vital for hair health, like protein, iron, and zinc, which can worsen thinning.
• For most people, this condition is temporary, with hair typically beginning to regrow within 3-6 months as the body adjusts and nutrition stabilizes.

Have you been noticing more hair in your brush or shower drain while taking Mounjaro? It’s natural to wonder if there’s a connection between hair loss and the medication – and if there’s anything you can do about it.

It’s a valid concern, but here’s some reassurance: Mounjaro itself isn't the direct cause of hair loss. The real culprit is the significant weight loss that often comes along with the medication.

Let's explore the science behind why this happens, the crucial role nutrition plays, and the practical, evidence-based steps you can take to support healthy hair growth during your weight loss journey.

Is it Mounjaro or the weight loss?

You may have checked your Mounjaro box to look at the official prescribing information to see if hair loss (alopecia) is listed as an official side effect. Most of the side effects are gastrointestinal, and hair loss isn’t on the list.

The primary cause of hair loss while taking Mounjaro is the rapid, significant weight loss that many people experience. This isn't unique to Mounjaro; it's a well-documented phenomenon in general weight loss. Individuals who lose weight quickly through other means, such as bariatric surgery or very-low-calorie diets, frequently report the same experience with hair thinning.

Rapid weight loss is a major physical stressor to the body. As a result, it shifts its resources away from non-essential functions – like growing hair – to prioritize vital bodily processes.

Understanding telogen effluvium: the real reason for hair thinning

The specific type of hair loss linked to rapid weight loss has a medical name: telogen effluvium. While it sounds complex, the mechanism is quite clear once you understand your hair's natural lifecycle.

Your hair's natural growth cycle

At any given time, every hair follicle on your head is in one of three main phases:

• Anagen (the growing phase): This is the active phase where hair grows. It lasts for several years, and about 85-90% of your hair is in this stage right now.
• Catagen (the transition phase): A brief, transitional stage where the hair follicle shrinks.
• Telogen (the resting/shedding phase): The follicle rests, and the hair eventually sheds. Typically, only about 10-15% of your hair is in this phase, which is why shedding up to 100 hairs a day is perfectly normal.

How rapid weight loss disrupts the cycle

A significant stressor like rapid weight loss acts as a shock to your system. This shock can prematurely push a much larger percentage of your growing hairs (anagen) into the shedding phase (telogen).

Because the telogen phase lasts for a few months before the hair shaft actually falls out, you typically won't notice the increased shedding until about 2 to 4 months after your weight loss begins. This delay is often a source of confusion, as the hair loss becomes apparent when you're already well into your health journey.

The good news is that telogen effluvium is a diffuse, non-scarring form of hair loss, which means it's generally reversible once the underlying trigger is addressed and your body adapts.

The critical role of nutrition in hair health

Mounjaro's effectiveness comes from its ability to slow digestion and reduce appetite, which is great for weight loss. However, eating less overall can make it a challenge to get all the essential nutrients your hair requires to grow strong.

An inadequate intake of key vitamins and minerals is a well-established factor that can contribute to and worsen telogen effluvium.

“Nutrients of concern while on a GLP-1 are the same that most Americans struggle to get enough of: vitamin D, B12, iron, calcium, magnesium, and zinc,” says Mayci Herbert, RD.” I recommend getting baseline and follow-up labs drawn periodically to monitor these nutrients, and I would consider supplements when appropriate.”

Protein is the building block of hair

Your hair is made almost entirely of a protein called keratin. When your protein intake is too low, your body must ration its supply for more critical functions. Since hair growth isn't vital for survival, it's one of the first processes to be down-regulated. A lack of dietary protein can lead to hair that is brittle, weak, and sheds more easily.

Iron and zinc are essential minerals

Iron deficiency is one of the most well-established nutritional causes of hair loss, especially in women. Iron is essential for producing hemoglobin, which carries oxygen to your cells, including your hair follicles.

Zinc is another critical mineral for hair tissue growth and repair. Evidence shows a clear link between zinc deficiency and hair loss, making adequate intake crucial for a healthy scalp and strong hair.

Biotin & other key vitamins

Biotin (vitamin B7) gets a lot of attention for hair growth, but it's most impactful for those with a true deficiency, which is uncommon. That said, ensuring you get enough of all B vitamins, along with vitamins A, C, D, and E, supports your overall health, which in turn fuels your hair follicles.

Practical steps to manage hair loss on Mounjaro

While you can't stop telogen effluvium in its tracks, you can create the best possible environment for your body to recover and promote healthy regrowth.

“As Mounjaro reduces appetite, quality matters more than quantity,” says Mayci Herbert, RD. “Focus on small, frequent meals, prioritizing fruits, vegetables, whole grains, lean proteins, nuts, and seeds while minimizing ultra-processed foods. To avoid loss of lean muscle mass, aim for 20-30 grams of protein at each meal.”

1. Prioritize protein at every meal

With a reduced appetite, every bite counts. Make it a goal to include a source of lean protein with every meal and snack to give your body the essential building blocks for hair.

Examples: Grilled chicken or fish, eggs, Greek yogurt, cottage cheese, tofu, beans, and lentils.

2. Focus on nutrient-dense foods

Choose foods packed with vitamins and minerals. This strategy helps you get the most nutritional value from a smaller volume of food.

Examples: Leafy greens like spinach (an excellent source of iron), colorful vegetables, berries, nuts, and seeds.

3. Address nutritional gaps strategically

Before you start taking a random assortment of supplements, it's best to work with your healthcare team. Ask your doctor for a blood test to check for common deficiencies, like iron (ferritin), vitamin D, and zinc. Based on those results, a registered dietitian can help you develop a food-first plan to correct any deficiencies through your diet, and your doctor can recommend specific supplements if needed.

4. Be gentle with your hair

While you're experiencing increased shedding, it's wise to minimize any additional physical stress on your hair.

• Avoid tight hairstyles that pull on the roots
• Reduce the use of high-heat styling tools
• Use a wide-tooth comb and a gentle, sulfate-free shampoo

5. Manage your stress

Because stress is a known trigger for telogen effluvium, incorporating stress-management techniques is highly beneficial. Simple activities like walking, yoga, meditation, or prioritizing quality sleep can support your overall well-being and, by extension, your hair.

Will my hair grow back?

For the vast majority of people experiencing telogen effluvium from weight loss, the definitive answer is yes. This form of hair loss is temporary.

Once your weight stabilizes and your body adapts to its new normal, the hair growth cycle begins to correct itself. The follicles that were pushed into the shedding phase will re-enter the growth phase, and new hairs will begin to grow.

Patience, however, is essential. Hair grows slowly – about half an inch per month on average. It can take several months, and sometimes up to a year, to see a noticeable improvement in your hair's thickness and volume.

Final thoughts

Discovering that your hair is thinning while on Mounjaro can be disheartening, but understanding the underlying cause is the first step toward managing it effectively. This shedding is a sign that your body is undergoing a significant—and positive—transformation, which requires dedicated nutritional support.

By focusing on a protein-rich, nutrient-dense diet, you provide your body with the tools it needs to not only sustain your weight loss success but also to regrow healthy, strong hair.

Navigating your specific nutritional needs during such a significant change can be complex. A registered dietitian can create a personalized eating plan to ensure you’re getting adequate protein and essential nutrients to support both your hair and your overall health as you achieve your goals with Mounjaro.

Frequently asked questions

How much hair loss is normal on Mounjaro?

The amount of shedding varies, but it is typically diffuse, meaning you'll notice general thinning all over rather than distinct bald patches. You might see more hair than usual in the shower, on your clothes, or on your pillow. If hair loss is severe or patchy, it is crucial to see a doctor to rule out other medical conditions.

Can low iron from Mounjaro cause hair loss?

Mounjaro does not directly cause low iron. However, if your reduced appetite leads to a lower intake of iron-rich foods like red meat, beans, or spinach, an iron deficiency could develop. Since iron deficiency is a very common and reversible cause of hair loss, having your doctor check your levels is a proactive step.

How long does hair loss last after weight loss?

The active shedding phase of telogen effluvium typically lasts for 3 to 6 months. After this period, the shedding rate should return to normal. Regrowth will begin, but it will take several more months for the new hair to grow long enough to contribute to your hair's overall volume and thickness.

What vitamins should I take for hair loss during weight loss?

It is always best to get a blood test to identify specific deficiencies before starting supplements. If a deficiency is confirmed, common supplements that can help include iron, vitamin D, and zinc. A high-quality multivitamin can also serve as a good baseline. Always consult your healthcare provider before adding any new supplements to your routine.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.