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Amino Acids for Hair Growth

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Steph Coelho

Published 09/17/2017

Updated 04/25/2024

Your body needs nutrients to produce healthy strands. If you’re dealing with excess shedding, you might be wondering about amino acids for hair. So is amino acid good for hair? Put simply, yes.

Amino acids are crucial for healthy hair growth. But an amino acid supplement won’t do much to remedy a receding hairline or balding. Like many appearance-related issues, hair loss is a huge industry with myriad treatments built around junk science. So although your hair needs amino acids, they aren’t the be-all and end-all.

Read on to find out more about amino acids, their role in the body, what the science says about amino acids for hair growth and other research-backed hair loss treatments to consider.

Amino acids are vital for hair growth. These compounds make up keratin, the structural protein hair is made of. Some studies suggest that certain amino acids, including lysine and cysteine, can boost hair health by preventing breakage and encouraging growth.

We’ll get deeper into the benefits of amino acids below.

Amino acids are organic compounds that act as the building blocks of proteins. 

In total, 22 different amino acids make up proteins. These amino acids fall into three groups: essential amino acids, nonessential amino acids and conditional amino acids.

Essential Amino Acids

The human body can produce nine essential amino acids on its own. You can get them through food or dietary supplements.

They include:

  • Histidine

  • Isoleucine

  • Leucine

  • Lysine

  • Methionine

  • Phenylalanine

  • Threonine

  • Tryptophan

  • Valine

Some foods are complete proteins, meaning they contain all nine essential amino acids. Meat, fish, dairy products and eggs are complete proteins. A few plant foods are as well, like quinoa and pistachio nuts.

Nonessential Amino Acids

Your body can produce nonessential amino acids (also known as dispensable amino acids) without eating particular foods or taking supplements.

Some nonessential types of amino acids include:

  • Glycine

  • Alanine

  • Arginine

  • Tyrosine

  • Proline

  • Serine

If you don’t get enough of these amino acids from your diet, your body can make them using skeletal muscle, water and tissue.

Conditional Amino Acids

These amino acids aren’t usually essential. However, people may need more of them during periods of growth (like during pregnancy or puberty) or physical or mental stress.

Contrary to what the supplement industry might tell you, you don’t need to eat precise amounts of each amino acid with every meal. 

Still, eating a balanced diet that includes all of the essential amino acids goes a long way in optimizing overall health and well-being.

What do amino acids actually do? If you paid attention during biology class, you probably know that proteins, which are made up of amino acids, are the “building blocks of life.”

Amino acids play an important role in several bodily processes, including muscle growth, tissue maintenance and the production of certain hormones. In some cases, they might even provide your body with energy.

Other amino acid benefits include:

  • Neurotransmitter production. The essential amino acid phenylalanine helps the body make tyrosine, dopamine, norepinephrine and epinephrine — neurotransmitters that help regulate mood, cognitive function and behavior.

  • Skin and connective tissue repair. Threonine, another amino acid, plays a key role in producing skin and connective tissue.

  • Growth hormone production. The amino acid leucine helps regulate the production of growth hormones.

  • Histamine production. The amino acid histidine is essential for creating histamine — another neurotransmitter your body uses to maintain your sleep-wake cycle, aid in digestion and promote healthy sexual function.

The bottom line? Your body needs amino acids to function.

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Amino acids are essential for hair growth. They make up keratin, which is what hair is made of.

But that doesn’t mean you can rely on amino acid supplements to give you a full, healthy head of hair.

Some recent research suggests that amino acid supplements containing taurine, cysteine, methionine and other nutrients like collagen, iron and selenium can boost the effects of clinical hair loss treatments. That said, it’s unclear if the amino acids or the other nutrients are doing the heavy lifting.

A small 2022 study involving 30 women with chronic telogen effluvium (a form of hair loss) noted no link between amino acid levels and hair loss severity. According to the authors, supplementing with amino acids likely has no benefit. 

In the end, research drawing a clear link between amino acids and improvements in hair growth is lacking.

Research into the effects of amino acids on hair is limited. But some studies have found that specific amino acids, like cysteine and lysine, may benefit hair health, improving strength, encouraging growth and preventing breakage. 

Amino acids account for a large percentage of your hair’s chemical structure. 

Here’s what the research says about specific amino acids for hair growth.

Cysteine

About 18 percent of keratin consists of the amino acid cysteine.

A couple of small studies have linked cysteine supplementation to improvements in hair growth:

  • In a study published in the Journal of Applied Cosmetology, volunteers took a cysteine supplement for 50 weeks. On average, they experienced a 50 percent increase in hair growth. However, this study was small, with just 48 participants, and only 12 took the cysteine supplement.

  • In a 2007 study, researchers found that a dietary supplement containing L-cystine (a form of cysteine) and other active ingredients improved hair growth in women with telogen effluvium hair shedding. But we can’t rule out the other ingredients as a cause for regrowth, and that none of the participants had pattern hair loss or alopecia.

Lysine

Research suggests that the amino acid lysine significantly impacts hair strength and may be a possible treatment for hair loss.

It’s primarily found inside the hair root and helps hair retain its shape, volume and elasticity.

There’s some evidence that pairing lysine with iron may help limit hair shedding in women with nutritional deficiencies. However, lysine may not help with male or female pattern baldness, which results from the effects of genes and hormones.

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Scientists have dug into the potential effects of applying amino acids directly to hair.

Chemical reactions (like the effects of sun exposure or from styling or coloring your hair) can deplete proteins and amino acids in the hair. So this research has largely focused on the effects of hair products on hair health and strength rather than hair loss or growth. 

For example, a 2005 study published in the Journal of the American Academy of Dermatology showed that hair can lose six amino acids due to environmental or chemical damage but that you can reintroduce some of these amino acids through topical hair care products.

Using hair care products containing amino acids might help strengthen your hair. But this probably won’t do much to treat hair loss — unless your hair loss is due to damage from coloring, heat treatments, sun exposure or environmental factors.

The Best Products With Amino Acids for Hair Growth

Here are a few well-reviewed amino acid shampoos that may help strengthen your strands:

  • Nexxus Amino Bond Shampoo. This shampoo is formulated especially for damaged hair and contains five essential amino acids. 

  • Kiehl’s Amino Acid Shampoo. This gentle formula contains amino acids and coconut oil and is designed to help restore hair health and prevent frizz.

  • Ouai Fine Hair Shampoo. This lightweight formulation contains keratin and biotin.

While amino acids are essential for health and strength, there’s no evidence that they can treat male pattern baldness.

That said, proven, science-based medications are available. These treatments can slow, stop and, in some cases, even reverse the effects of genetic hair loss.

  • Finasteride. Finasteride is a prescription medication for hair loss. It works by stopping the production of the hormone dihydrotestosterone (DHT), which causes male pattern baldness.

  • Minoxidil. Minoxidil is a topical medication you apply to your scalp. It works by moving hairs into the anagen (growth) phase of the hair growth cycle. It may also increase blood flow to your hair follicles, supplying them with the nutrients needed for optimal growth. Minoxidil comes in foam and liquid formulas. 

Finasteride and minoxidil are available as part of our range of hair loss treatments and in this Hair Power Pack.

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Amino acids are essential for building muscle tissue and maintaining healthy skin, nails and hair.

Here’s the bottom line on amino acids for hair growth:

  • In rare cases, there may be a link between hair thinning and amino acid deficiencies. But the majority of cases in men result from male pattern baldness, which is unrelated to amino acid intake.

  • Protein deficiency in the U.S. is very rare. When it does happen, it’s usually because someone doesn’t eat enough food in general rather than a simple lack of animal-based protein.

  • There’s no convincing scientific evidence that amino acid supplementation or topical amino acid products can improve hair growth in men.

  • If hair loss is related to a protein deficiency, the best way to treat it is to eat more protein-packed foods.

  • You can treat and prevent genetic hair loss with science-based medications like finasteride and minoxidil.

If you’re experiencing hair loss, consider talking with a healthcare professional to discuss hair loss treatment options.

Our virtual consultations make it quick and easy to get help for hair problems.

20 Sources

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  8. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6288, L-Threonine. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/L-threonine
  9. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6106, Leucine. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/L-leucine
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  13. Morganti, P., Fabrizi, G., James, B. and Bruno, C. (1998, July-September). Effect of Gelatin-Cystine and Serenoa Repens Extract on Free Radicals Level and Hair Growth. Journal of Applied Cosmetology. 16, 57-64. Retrieved from http://iscd.it/files/EFFECT-OF-GELATIN-CYSTINE-ANO-SERENOA-REPENS-EXTRACT-ON-FREE-RAOICALS-LEVEL-AND-HAIR-GROWTH.pdf
  14. Lengg, N., Heidecker, B., Seifert, B. R.M. (2007, January). Dietary supplement increases anagen hair rate in women with telogen effluvium: Results of a double-blind, placebo-controlled trial. 4 (1), 59-65. Retrieved from https://www.researchgate.net/publication/244933760_Dietary_supplement_increases_anagen_hair_rate_in_women_with_telogen_effluvium_Results_of_a_double-blind_placebo-controlled_trial
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Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Knox Beasley, MD

Dr. Knox Beasley is a board certified dermatologist specializing in hair loss. He completed his undergraduate studies at the United States Military Academy at West Point, NY, and subsequently attended medical school at Tulane University School of Medicine in New Orleans, LA. 

Dr. Beasley first began doing telemedicine during his dermatology residency in 2013 with the military, helping to diagnose dermatologic conditions in soldiers all over the world. 

Dr. Beasley is board certified by the American Board of Dermatology, and is a Fellow of the American Academy of Dermatology.

Originally from Nashville, TN, Dr. Beasley currently lives in North Carolina and enjoys spending time outdoors (with sunscreen of course) with his wife and two children in his spare time. 

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