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Protein Deficiency Hair Loss: Can a Lack of Protein Cause Hair Loss?

Katelyn Hagerty

Reviewed by Katelyn Hagerty, FNP

Written by Rachel Sacks

Published 04/16/2023

Can a lack of protein cause hair loss? Here’s everything you need to know.

If you feel like more hair is going down your shower drain or that your hairline is moving farther back each day, you’re not alone. Between 30 and 50 percent of men will experience male pattern baldness, the most common form of hair loss, by age 50.

Male pattern baldness is often a hereditary hair loss, meaning it’s caused by genetics rather than dietary practices. However, not everyone has a genetic predisposition to receding hair, and other types of hair loss can be connected to what you eat.

We know that eating a healthy diet full of leafy greens, whole grains and protein keeps us strong and healthy, thanks to the various nutrients and essential vitamins we get from these foods. On the flip side, a poorly balanced diet can lead to a nutritional deficiency, with one of the results being potential hair loss. So can a lack of protein or namely can vegetarian diet cause hair loss?

Protein isn’t just for growing muscle mass — it’s important for healthy hair growth and may be vital in preventing hair loss too.

You don’t have to go searching “can lack of protein cause hair loss” or “protein deficiency hair loss” to find the answer. Keep reading to learn about the connection between protein deficiency and hair loss, as well as how to treat hair loss.

The question at the top of your mind: can lack of protein cause hair loss?

As mentioned above, a healthy diet can keep hair healthy due to essential nutrients. Vitamins and minerals from food play an important role in the hair growth cycle, and a lack of essential nutrients may cause hair loss — including protein.

Hair is made up of two main structures — the hair shaft (the hair we see) and hair follicles underneath the skin. The hair growth cycle undergoes three phases:

  • Anagen phase. This phase occurs when hair is growing and can last several years.

  • Catagen phase. The catagen phase is a short transitional period that lasts a few weeks.

  • Telogen phase. The telogen phase is a rest phase of three to four months. At the end of this stage, the hair falls out and new hair grows in the hair follicles.

Though it may not seem like it, your hair is constantly growing. About 90 percent of your hair follicles are in the anagen phase at any given time, which is when a variety of nutrients are essential.

When you fail to get sufficient protein from your diet, your body attempts to conserve protein by forcing your hair follicles into a resting state. This results in hair shedding approximately two to three months after switching to a diet low in protein.

A 2017 review of multiple studies suggests that hair growth may be impacted by protein malnutrition, although more research is needed to fully understand the connection between nutrients and hair loss.

But how, specifically, are protein deficiency and hair loss connected? Simply put, hair is made of protein. The hair shaft consists of several different proteins, including keratin protein.

Protein is made up of amino acids, organic compounds that help the body repair tissue, break down food, grow and perform other functions. Different kinds of amino acids make up protein:

  • Essential amino acids. Nine essential amino acids can’t be produced internally by your body and need to be consumed via food or dietary supplements.

  • Nonessential amino acids. Also known as dispensable amino acids, these can be produced inside your body.

  • Conditional amino acids. These usually aren’t essential but can be crucial when you’re sick or stressed.

Amino acids play an important role in several processes within the body, including muscle mass growth and repairing muscle tissues. They're essential for your body and all its proteins — including those that make up your hair.

So a lack of protein can lead to hair loss. How do you know if you have a protein deficiency and if it’s the cause of your hair loss? We’ll get to that below.

Can lack of protein cause hair loss? It’s very possible. But how do you know if you’re not getting a sufficient protein intake and if it’s causing temporary hair loss or more severe hair loss?

Many foods contain protein, and while protein intake can vary from person to person, many people in the U.S. and other developed countries meet their daily protein requirement.

The recommended daily amount is only 0.8 grams of protein per kilogram of body weight — or just over 7 grams of protein for every 20 pounds. A nutritional deficiency of protein is still possible if you have a restrictive diet, such as a vegetarian or vegan diet.

Following a vegetarian or vegan diet low in certain nutrients may increase your risk of developing nutritional deficiencies that can cause hair shedding. Hair loss isn’t always a side effect of a vegetarian or vegan diet, though.

The risk of hypoproteinemia — low protein levels in your blood — isn’t a common problem. Your healthcare provider may run a total protein test to check your nutrient profile and the total amount of protein in your blood.

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If you believe you’re experiencing protein deficiency hair loss, there are ways to increase your protein intake.

Diet is the easiest way to increase protein, as there are plenty of protein-rich food sources.

Lean meat is a good source of protein as well as poultry and eggs. Beans, lentils and nuts are other adequate sources of protein. Fatty fish and other oily fish like salmon are not only a good source of protein, but they also contain omega-3 fatty acids, another critical nutrient for hair health.

Hair loss supplements are popular, as are dietary supplements for nutritional deficiencies. But while there have been studies on amino acid and protein supplements, these dietary supplements were made with a variety of nutrients.

Also, we can’t say for sure if they worked unless it’s clear the person had a true nutritional deficiency. So it’s unclear whether protein supplementation played a role in hair growth or loss in these particular studies.

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The most effective way to treat and reverse hair loss due to a protein deficiency is to make sure you’re eating healthy sources of protein. However, you may also be able to use medication to stimulate hair growth and speed up the process of restoring your normal hair thickness and density.

Medications like finasteride won’t have an effect on diet-related hair loss, as this form of hair loss isn’t caused by hormones.

But a topical hair loss medication like minoxidil may help speed up the regrowth process and restore your hair faster. This medication works by improving blood flow to your scalp and stimulating your hair follicles.

Our guide on how to apply minoxidil for hair growth goes into more detail on how this medication works to restore the loss of hair.

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Can lack of protein cause hair loss? It’s possible since hair is made up of protein. Protein consists of amino acids that help repair muscle tissue and contribute to strong, healthy growing hair. As the building blocks for muscles, skin and hair, protein and amino acids are an essential part of your nutrient profile.

If you consume a low-protein diet, you might notice thinning hair or more hair breakage a few months after your protein consumption has decreased.

Although protein deficiencies are fairly unlikely, you can always try to add more protein-rich foods to your diet, like eggs, nuts, beans, fatty fish and poultry.

Unlike hair loss caused by male pattern baldness, hair loss caused by a restrictive diet, including certain vegetarian and vegan diets, usually isn’t permanent, meaning your hair should grow back once the underlying issue is treated.

If you’re starting to lose your hair, you can talk to a healthcare provider online to learn more about causes and treatment options. Get started today.

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  11. Total Protein and Albumin/Globulin (A/G) Ratio. (2021, October 5). MedlinePlus. Retrieved from https://medlineplus.gov/lab-tests/total-protein-and-albumin-globulin-a-g-ratio/
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