Protein and Hair Growth: Why It Matters for Healthy Hair

Key Takeaways:

• Protein is the building block of healthy hair. Since hair is mostly made of keratin — a structural protein — your body needs enough dietary protein to produce and maintain strong, healthy strands.

• Not getting enough protein can lead to weak, brittle, or thinning hair. A protein deficiency limits keratin production, which can cause hair to break more easily or even trigger temporary hair shedding (telogen effluvium).

• Most people meet their protein needs through diet. While supplements aren’t usually necessary, eating a balanced mix of protein-rich foods — like eggs, fish, soy, and lentils — supports hair growth and overall health.

• Topical protein products strengthen but don’t regrow hair. Keratin treatments or protein shampoos can improve elasticity and reduce breakage, but they won’t promote new growth.
  

Can eating a bunch of steak reduce hair loss? Not exactly, but the link between protein and hair is very important when it comes to your hair’s health. Here we’ll cover what science says about protein and hair, signs you’re not getting enough protein, your dietary needs and food sources, and when it makes sense to supplement.

Hair is made up primarily of a protein called keratin. In fact, what you see when you look at hair (the hair shaft) is simply hardened keratin, and the structural protein also makes up the outer layer of the skin and nails. Research shows that dietary protein (protein you eat) is “critical for the production of normal, healthy hair.” 

Protein provides the body with the amino acids it needs to produce adequate keratin to support hair growth. So what happens if you don’t get enough protein? Your body may not have the amino acids it needs to be able to produce enough keratin, which can lead to weak, thin, or more brittle hair.

If you’re not getting enough protein, the keratin you produce is weak, which means your hair may be brittle and break easily, and it may be more easily damaged by things like heat styling, friction, or UV rays.

Here are some signs that your body is lacking protein:

• Brittle hair

• Brittle, peeling, or thinning nails

• Fatigue and weakness

• Mood changes

• Brain fog

• Frequent illness or infection

• Increased hunger

• Edema (a swelling due to excess fluid in tissues or an organ)

The exact amount of protein you need to eat per day depends on several factors, including your height, weight, age, and sex. However, as a general guideline, the Recommended Dietary Allowance (RDA) for protein in people 18 years and older is 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound. Keep in mind that the number is the minimum amount you should be eating a day.

If you’re looking for more hard-and-fast guidelines,  the U.S. Department of Agriculture’s 2020–2025 Dietary Guidelines for Americans states that men need around 56 g for overall health, including hair growth. 

However, despite all the protein powders and supplements you likely see advertised, research shows that most Americans do meet their daily protein requirements through diet and should not need protein powders for hair growth (they can be helpful if you’re trying to build muscle, however).

Check out our protein calculator to learn more about your specific protein needs.

Yes, a lack of protein can cause hair loss, but in most cases, the hair thinning or shedding is temporary and can be reversed once you start eating adequate protein. This type of temporary hair loss is known as telogen effluvium.  

Research on individuals living with eating disorders found that hair conditions, including alopecia, brittle or opaque hair, and diffuse hair thinning, affect as much as 61 percent of people. The research went on to say these hair changes were due to internal protein depletion. 

A review of several studies also found that people with diets lacking complete proteins (foods that contain the nine essential amino acids that the body cannot produce on its own) may experience hair loss.

Wondering how to get more protein in your diet? Below, we’re sharing a list of foods that contain all nine essential amino acids, making them complete proteins, plus other sources of protein.

• Meat (beef, chicken, lamb, pork)

• Eggs

• Fish

• Nuts

• Dairy products

• Soybeans & tofu

• Hempseed

• Chia seeds

• Quinoa 

• Buckwheat

Other protein-rich foods that are not essential proteins include:

• Beans

• Lentils

• Nuts

• Oats

• Brown rice

• Certain vegetables, including spinach and leafy greens, broccoli, and Brussels sprouts

Many people also wonder about protein treatments for hair growth, such as keratin treatments or hair products like shampoos and conditioners that include protein. These topical formulations are designed to temporarily strengthen and repair hair by coating the individual strands with proteins like keratin, collagen, or silk amino acids. 

Research shows that these products can help to strengthen hair and reduce breakage while improving elasticity,  but they don’t promote hair growth.

Getting enough protein is key for strong, healthy hair, but it’s not a magic fix for hair loss. A balanced diet that includes a variety of nutrient-rich foods supports keratin production and overall scalp health. While protein treatments can help repair damage, lasting hair strength starts from within.

If you are unsure what is causing your hair loss, always speak to a dermatologist or other healthcare provider who can help you discern the cause.

Can whey protein cause hair loss?

While a very small study suggested a link between whey protein and male pattern baldness, to date, there is no clear association between whey protein and hair loss.

Can too much protein cause hair loss?

Excessive protein intake is not linked to hair loss. However, in some cases, overdoing protein supplements or crash diets that are protein-heavy but lacking other nutrients could potentially lead to nutritional imbalances that contribute to hair loss.

Does higher protein intake improve hair?

If you are not getting enough protein, then yes, increasing your protein intake can make hair stronger and more vibrant. However, if you are already meeting your protein needs and are still noticing hair loss or other hair conditions, protein is probably not the culprit.

Does a lack of protein cause balding?

No, inadequate protein consumption is not a factor in male pattern baldness. This type of hair loss is caused primarily by genetics.

To learn more, check out our guides to keratin vs biotin.