Given that up to 95% of your hair is composed of keratin [1], it’s natural to wonder whether protein helps hair growth. And the answer is that it can absolutely help, provided that you are eating a balanced diet that helps you produce enough of it.
Malnutrition caused by protein deficiency has been known to impair hair growth and even contribute to certain types of alopecia [2][3]. However, there is insufficient evidence that supplementing protein can help stimulate hair follicles for growth in a healthy person with no protein deficiency. Moreover, while many keratin hair treatments promise to help your strands grow denser or faster, it is a good idea to be weary of those claims.
Some might make your hair smoother, shinier or even stronger, but there is no evidence protein can improve hair growth by being applied topically to the scalp and hair [4]. Moreover, some of these treatments can contain harmful substances such as formaldehyde [5].
This article will tell you everything you need to know about how to harness protein’s benefits for your hair without falling for marketing myths. Keep reading to discover:
Proteins are some of the building blocks that make up our body’s structures and functions. They are large molecules which contain combinations of 20 amino acids grouped together in longer or shorter chains called polypeptides, according to genetic instructions. Different kinds of protein play a variety of vital roles in your body [6]:
Basically, proteins are a cornerstone of all biological structures and processes, which is why it is crucial to supply our body with all the nutrients it needs to be able to produce them.
Without a doubt, protein is vital to hair production. That is because it is mostly made of a type of protein called keratins. Your body produces 54 different kinds of these substances, some of which make up your nails, others make up your hair or become part of your skin [4]. 17 of them are considered hair keratins [7].
Hair keratins are produced by your body using chains of amino acids (molecules that combine to form protein). Such amino acids are usually encountered in hair composition, some of the most common of them being lysine, cysteine, glycine, proline, arginine and threonine [8]. They are obtained mainly from various foods you eat, so it is important to have a healthy, balanced diet.
Getting insufficient protein can deprive your body of the resources it needs to make your hair grow, and it can push existing strands out of the growth phase and into the shedding phase. When the growth phase is cut short for a larger proportion of your hair than normal, it triggers a type of alopecia called telogen effluvium [9], which manifests with diffuse hair thinning as too many of your strands have started to shed. Fortunately, this condition is temporary, so fixing your protein deficiency is likely to help resume normal hair growth in 3-4 months.
The recommended dose of protein that you need to consume every day to maintain your health depends on your body weight. You should ideally get 0.8 g/kg [10]. However, not all proteins are created equal, you need to get different kinds of amino acids to produce all the types of chains you need. That is why a healthy, varied diet is important.
As long as you are a healthy person consuming the necessary amount of protein, it should be sufficient for the good functioning of your body. Research shows no hair benefits to exceeding the daily recommended values, and some scientists are concerned that getting too much protein may have harmful effects on your health [11] (though more studies are needed to explore this).
These risks are not necessarily related to protein itself but rather to the excessive intake of certain foods that contain it (e.g. fatty meat, too many eggs, etc.), which can raise your cholesterol levels and put a strain on your cardiovascular, digestive and excretive system. That is why many physicians recommend getting a higher amount of protein from plant sources [12].
Your hair falls under the same category as the rest of your body – if you are getting the necessary amount of protein, your strands should have all the building blocks they need for healthy growth. Upping the intake will not improve this process, so there is no need to try to consume greater amounts. However, eating a diverse, healthy diet for hair, containing foods that are rich in vitamins and minerals, can help improve the quality of your strands.
In order to grow strong and thick, your hair needs many nutrients, such as vitamins A, B, C, D and E, iron, zinc, selenium, magnesium and more [13]. Vitamin deficiencies can sometimes cause hair loss through mechanisms similar to protein deficiency. That is why the best sources of protein for your hair contain an abundance of these micronutrients.
Here are some of the best hair growth foods that can boost your protein intake and help your strands remain healthy:
While protein deficiency is rare in developed countries, it is not unheard of. It can occur for many reasons, the most common of which are malnutrition (often caused by eating disorders or restrictive diets) and liver or kidney disease [15]. The main signs and symptoms that you may have such a deficiency include [16]:
If you suspect you may be experiencing a protein deficiency, contact your healthcare provider and get a total protein test.
There are many shampoos, conditioners and topical treatments that contain hair protein such as keratin. The companies that sell them often boast spectacular results, such as improving your hair growth or density. However, at this time, there is no scientific evidence that they can deliver on these promises.
That is because we have no proof that topically applied keratin can penetrate the hair shaft [4] or that it can be properly absorbed into the scalp and significantly impact the hair follicle. This is especially true for shampoos, which contain small quantities of protein and are generally left on the hair for short amounts of time, likely insufficient to achieve good scalp or hair shaft penetration.
Moreover, scientists warn that some hair treatments containing keratin can also contain dangerous substances, such as formaldehyde [5]. This is a known carcinogen, which means it can increase your risk of developing cancer.
However, using hair care products that contain keratin or other kinds of hair protein from eggs, wheat, whey, or other sources can also have a positive effect on your hair by making it look smoother, shinier and easier to style. Keratin is also known to help smoothen your curls, which is why it is sometimes used as a milder alternative to hair relaxers. So a good quality protein hair treatment that follows all health and safety protocols can positively affect your hair, especially in combination with other nourishing ingredients.
Unfortunately, there are too few studies performed on this topic. Some small clinical trials had patients with telogen effluvium take\L-cystine supplements, with promising results. This substance can be converted by your body to the amino acid cysteine, required for protein synthesis. However, the tested supplements also contained other hair health-boosting components, such as B-complex vitamins and medicinal yeast or other nutrients [17].
In the absence of human trials performed with protein or amino-acid dietary supplementation alone, there is currently no indication to take protein dietary supplements for hair growth [18]. Eating a diverse, nutrient-rich diet should be sufficient to provide optimal strand production in healthy people.
When it comes to protein and hair health, it isn’t only about making sure you produce enough keratin to keep your hair growing and thriving. You also need to worry about protecting the protein in your already-developed strands.
Certain harsh chemicals used for colouring or styling your hair can actively damage your strands. Frequent bleaching, for example, can break the protein bonds within your strands, leaving you with dry, brittle hair that is structurally damaged and breaks very easily [8]. If it contains hydrogen peroxide, hair dye can also cause hair loss through a similar process – by causing protein loss [19].
So if you want to preserve your beautiful, strong, shiny hair, it is a good idea to avoid hair treatments that contain chemicals that can damage its keratin. And if you do get these treatments, make sure to use nourishing hair masks and the best hair growth oils that can moisturise your strands and help restore their strength and elasticity.
There is evidence that protein deficiency can cause hair thinning, mainly through two mechanisms. On the one hand, it can deprive your hair follicles of the nutrients and resources they need to produce healthy strands. This can disrupt your normal hair growth cycle, triggering telogen effluvium.
On the other hand, insufficient protein can make your hair weaker and more brittle, making it more prone to breaking off. This can cause mechanical thinning. However, more research is needed to determine the exact impact of protein deficiency on hair loss. If you believe that this may be the reason your hair is falling out, it is a good idea to see a hair doctor to exclude other possible types of alopecia.
If you are struggling to achieve hair growth or are experiencing unexplained hair thinning, you may be tempted to spend a lot on hair products that promise miracle treatments. However, you stand to gain much more from booking a consultation with a trichologist. You won’t need to be guessing about your hair health anymore because they will perform all the needed hair loss blood tests and diagnostic investigations to provide accurate answers.
Hair doctors can easily distinguish between different kinds of alopecia, help you understand why your hair is thinning and recommend the most effective, personalised treatments. And seeing them from the first signs of hair thinning and balding can significantly improve your chances of curbing hair loss and achieving regrowth.
However, postponing a trichologist visit can be risky if you have a condition such as androgenetic alopecia. If you are unaware of it and treat it with commercial hair products alone, it can advance to the point where only a hair transplant can help restore your locks.
If you haven’t found all the insight you were looking for in this article, you may find it by perusing the answers to these frequently asked questions:
While your strands are largely made of keratin, eating keratin will not produce hair or health benefits. That is because our stomach cannot digest it and it simply passes through our digestive system and is eliminated intact [17]. So there is no need to start biting your nails, just stick to eating a well-balanced, nutrient-rich diet.
Yes, once your protein deficiency has been resolved, your hair will start thriving once more. However, you may need to wait a few months for this to happen, as your natural hair growth cycle needs time to readjust and become regulated.
It depends on what the powder contains. Generally speaking, at this time, there hasn’t been extensive research regarding the effect of this dietary supplement on hair loss.
Some small studies suggest that whey protein might exacerbate already existing male pattern baldness (or female pattern baldness) by slightly raising your testosterone levels [20]. Still, more evidence is needed to demonstrate this effect.
Yes, if you are a vegetarian, you can get your daily recommended dose of protein from eggs, dairy, fortified cereal, fruit or vegetables. Even if you are vegan, plenty of foods can provide vegetable protein: nuts, seeds, beans, and leafy greens are some of your best options.
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