Why keto hair loss occurs—and how to stop it

If you’re on the ketogenic or keto diet and start noticing hair in the shower or on your comb, you’re not alone. Some people do experience hair loss while following a keto diet. This is usually due to nutrient deficiencies or simply not eating enough food. 

Fortunately, it’s usually temporary. Let’s look at why keto hair loss occurs and how you can reverse it.

Hair loss

FDA-approved finasteride, delivered to your door

Start now

Along with other side effects—like headache, nausea, fatigue, and more—often described as the keto flu, a keto diet can cause some to experience hair loss, because it changes the body’s metabolism. 

Usually, your cells use glucose from carbohydrates, as well as protein, for energy. If you are on the keto diet, this means you’re restricting carbs and limiting protein so that your body has to burn ketones (chemicals made in your liver from fat) for energy—a state called ketosis (Masood, 2020).  

To get into ketosis, many people count their “macros” or macronutrients—carbs, protein, and fat—to make sure they are eating a certain percentage of fat daily. A standard keto diet typically contains 70% fat, 20% protein, and only 10% carbs (Shilpa, 2018). Some boost protein to 35% while keeping carbs about the same. For a 2,000 calorie per day keto diet, carbs would make up about 20 to 50 grams per day (Masood, 2020). 

This restrictive diet approach can trigger hair shedding (Muscogiuri, 2019).

It can be hard to figure out the exact cause of hair loss. Genetics, metabolism and the nutrients people eat on a keto diet vary. There are also a variety of types of keto diets with different levels of fat, protein and carb ratios (Wells, 2020). 

However, there are some general reasons your hair may be falling out while on a keto diet: 

Cutting too many calories

Fat and protein can make you feel full. If you dramatically cut carbs, it can eventually lead to eating fewer calories overall because your body gets used to being in a state of ketosis and may not experience as much hunger (Masood, 2020). 

Calorie restriction leads to hormone changes. In response to a keto diet or intermittent fasting (when you alternate between eating and fasting for designated periods of time), studies show the stress hormone cortisol rises while levels of the thyroid hormone, triiodothyronine (T3), fall. Both high cortisol and low thyroid levels are linked to hair loss (Thom, 2016; Kim, 2021).

That said, it’s not clear what triggers the shedding in any given case for those on a keto diet. Research does show that low-calorie, low-carb diets are linked to a condition called telogen effluvium, which is often caused by stress, dieting, or a nutrient deficiency (Pham, 2020; Guo, 2017).

Rapid weight loss

Initially, those on a ketogenic diet may notice rapid weight loss of up to ten pounds in two weeks or less. The keto diet has a diuretic effect, so some early weight loss is water loss. That’s usually followed by fat loss afterward (Masood, 2020). 

Similar to cutting calories, weight loss signals to the body that there may be a scarcity of food, and it may be time to divert resources away from non-essential functions like hair growth. This may cause telogen effluvium (TE), which can occur about two to five months after dramatic weight loss begins (Aboud, 2021; Almohanna, 2018).

Not enough protein

Some on the keto diet limit protein to ensure they stay in ketosis, which requires a high fat-to-protein and carb ratio. And eating too little protein can cause hair loss. 

One study found that when protein in the body and diet is low, hair can thin as a result, which may be due to the body’s attempt at nutrient conservation and prioritization (Muscogiuri, 2019).

Nutrient loss

You need a lot of different nutrients to build healthy hair. Restricting calories and entire food groups—like carbohydrates if you’re on the keto diet—can limit your intake of the various vitamins and minerals your body needs to support hair health. 

Deficiencies in proteins, minerals, or vitamins can lead to or worsen telogen effluvium and other forms of hair loss—also known as alopecia—such as androgenetic alopecia, female pattern hair loss, or alopecia areata (Guo, 2017).

Keto hair loss is usually temporary. 

For instance, after TE hair loss, new hair typically begins to regrow in about two to three months. However, each case can be different depending on the exact cause. 

It’s important to reach out to your healthcare provider if you notice hair loss so they can rule out any medical conditions that could be separate from a keto diet side effect or could be putting you at higher risk for dietary hair loss.

They can test you for thyroid conditions or anemia. This is also a good chance to keep track of exactly what you’re eating, how often, and if the diet affects exercise or how you feel in general. 

Those who are placed on a keto diet for medical reasons, such as epilepsy or weight loss, are closely watched since keto can negatively affect kidney and heart function, along with cholesterol, electrolyte, thyroid, and glucose levels (Muscogiuri, 2019).

After checking with your healthcare provider about underlying medical conditions, if you find that your hair loss is likely related to the keto diet, it can also be helpful to discuss what may be lacking in your diet and if keto is right for you. 

If you plan to continue or start a keto diet, the following approaches can reduce the risk of hair loss: 

Expanding food variety 

Going keto doesn’t have to involve eating large amounts of bacon and butter. Many keto diet meals focus on healthy fats and proteins like avocados and chicken. Expanding the types of whole foods you eat can boost hair-healthy nutrients. 

This applies to vegan or vegetarian keto approaches as well. Expanding the types of plant-based proteins can help avoid a deficiency and add nutrients to the diet (Katz, 2019).

For those concerned about limiting protein, there are higher protein versions of keto. Studies show modified, less restrictive keto diets with moderate protein levels have fewer side effects (Wells, 2020).

To meet dietary and exercise needs, people are altering the standard keto diets even more to add intermittent carbs. Many bodybuilders and athletes utilize cyclical ketogenic and targeted ketogenic diet approaches. These involve cycling through periods of carb eating or targeting the eating of carbs around periods of intensive workouts to provide more energy (Shilpa, 2018; Terink, 2021).

Supplementing to avoid deficiencies

Getting enough vitamins and minerals is essential for healthy hair. If you notice hair falling out for any reason, talk with your healthcare provider about potential nutrient deficiencies instead of guessing what nutrients your body needs. 

For example, with hair loss, it’s common to supplement with vitamin D and iron. But, you have to actually be deficient in iron for supplements to make a positive impact. Supplementing with iron when you’re not deficient can be dangerous if you take too much.

Another example is biotin. Biotin supplementation may only be helpful in people who were deficient in biotin to begin with. And there are other vitamins that can actually lead to hair loss when taken in excess, such as vitamin A. This is why it’s best to work with your healthcare provider to correct deficiencies rather than risk over-supplementing (Almohanna, 2018).

Making changes gradually

Research shows the body is more likely to shed hair if the new diet is extreme. To avoid a drastic change, some suggest reducing carbs slowly leading up to a keto diet. And, if you plan to do intermittent fasting (IF) while on the keto diet, consider making that change gradually as well because fasting can have its own impacts on your body (Kim, 2021). 

In the case of weight management, healthcare providers typically advise that a keto diet be followed only in the short term (typically no more than a year) and that the transition back to a standard balanced diet should be gradual (Masood, 2020). 

Boosting scalp health

While avoiding nutritional deficiencies is the key to hair health, the following approaches can also help improve the health of your hair follicles which may lead to less hair shedding (Dias, 2015):

• Avoiding chemical dyes, straighteners, and perms

• Avoiding tight ponytails

• Massaging coconut oil into the scalp or letting it soak into the hair for a couple of hours or overnight (Studies show this can add moisture and combat protein loss.) 

The keto diet can cause hair loss in some people, but it’s usually temporary and often due to nutrient deficiencies. 

Beyond temporary hair loss and other short-term side effects, strict keto diets are also linked to longer-term health problems like heart disease, kidney problems, insulin resistance, and a decrease in bone density (García-Rodríguez, 2021). They also have the potential to cause dehydration, electrolyte imbalances, and hypoglycemia.

This is why it’s important to see your healthcare provider if you’re on the keto diet, especially if you start noticing hair loss. And, if you’re not yet on the keto diet, it may be a good idea to talk with your healthcare provider about whether going keto is right for you.

---

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Editorial Guidelines | Medical Review Process

Current version

April 13, 2022

Written by

Kristin DeJohn

Fact checked by

Raagini Yedidi, MD

---

About the medical reviewer

Raagini Yedidi, MD

Raagini Yedidi, MD, is an internal medicine resident and medical reviewer for Ro.