What Does Protein In Shampoo Do To Your Hair? [Solved!]

Protein is a vital nutrient needed for the growth and general health of your body and hair.

That’s why protein shampoo is commonly used in hair care, but how much of it should you use, and what does protein in shampoo do to your hair? Let’s look at the details.

What Does Protein In Shampoo Do To Your Hair?

Ever wondered what protein in shampoo does to your hair?

Protein shampoo helps treat damaged hair, and using protein shampoo regularly can make your hair fuller, shinier, healthier, and more elastic. However, too much protein in your hair can cause breakage. Noticing split ends and limp strands after a protein treatment is a common sign your hair is suffering from protein overload.

What Is Protein Shampoo?

Protein shampoo is a hair care product designed to cleanse the hair while delivering protein for added protection and strength in-between washes.

Besides cleansers and surfactants that remove oils and dirt from your har, protein-enriched shampoos typically contain all or some of the following types of protein:

  • Keratin. Keratin is a fibrous and structural protein that’s an important component of each hair strand. Its main function is to protect the hair.
  • Collagen. Collagen is another natural protein that’s found in your hair. It helps improve your hair’s health and support and enhances the benefits of protein shampoo.
  • Amino acids. Amino acids are the building blocks of protein, and they help nourish hair. 
  • Plant and animal proteins. Protein shampoo can contain plant and animal proteins, such as wheat protein, soy protein, milk protein, and silk protein that help keep the hair cuticle smooth and strengthen hair.

When shopping for protein shampoo, it’s best to look for products that contain hydrolyzed proteins for superior penetration of the hair shaft.

You should also look for a shampoo that contains gentle cleansers instead of harsh surfactants that strip away the hair’s natural oils.

How Can You Tell You Need a Protein Shampoo?

How Can You Tell You Need a Protein Shampoo

Does your hair need extra protein? Here are some signs to watch out for:

Your Hair Is Highly Porous

When your hair is highly porous, it’s in a weaker state because of the tears and gaps in the hair shaft.

This makes hair with high porosity even more vulnerable to environmental damage. 

For instance, there’s nothing preventing your hair from absorbing too much water and becoming frizzy and harder to manage when the cuticle is damaged.

Porous hair can also cause faster fading of color after color treatment.

You Have Chemically Treated Hair

Color-treated hair is popular if you want to make a fashion statement, but it can also leave your hair badly in need of protein treatment.

That’s because most hair dyes contain strong chemicals such as ammonia.

These strong chemicals can weaken the bonds of the hair, change the texture of the hair, and strip away natural moisture from hair follicles.

That’s why color treatments can result in split ends, breakage, hair loss, and dryness.

You Have Heat Damaged Hair

If your hair shows signs of damage because of excessive high-heat styling, it could benefit from protein shampoo.

High heat styling weakens and damages hair, so adding an extra coat of protein to each hair strand is necessary.

This creates a protective barrier composed of proteins that are naturally found in hair.

Common signs of heat damaged hair include having fly-away hair as well as brittle and dry hair that’s tougher to manage and breaks easily.

Your Hair Is Failing the Elastic Test

Healthy hair tends to have some elasticity to it.

Hair with a high level of elasticity is easier to style and will have the right amount of body and bounce.

However, if your hair loses some of this elasticity, it will have less natural-curl definition and resist your curling efforts.

So, how do you know when your hair loses some of its flexibility? 

Typically, it will fail the elasticity test, which involves stretching a strand of your hair when it’s wet.

When stretched, elastic hair will bounce back to its original position, but the hair strand will remain limp or break if there’s no elasticity.

This is a tell-tale sign that your hair could use protein shampoo to add more bounce and make your hair more amenable to styling.

You Have Curly Hair

When your hair is naturally curly, using a protein shampoo regularly can keep it manageable and prevent breakage.

Curly hair is typically more prone to breakage than straight hair. When the hair cuticle is broken, curly hair quickly becomes dry and frizzy and protein helps repair the problem.

What Does Protein in Shampoo Do to Your Hair?

What Does Protein in Shampoo Do to Your Hair

Here’s how protein in shampoo can benefit your hair:

Strengthens Hair

As mentioned, hair is mostly made up of keratin, which is also one of the main ingredients in protein shampoo.

External application of keratin ensures that your hair strands are coated with this protective protein.

Therefore, protein shampoo will strengthen your hair by restoring its nutrients.

Hydrates Hair

Protein shampoos contain not only different types of protein but also other extra ingredients, such as moisturizers.

For instance, ingredients like shea butter help dry hair to lock in more moisture.

Closes Cuticles

The cuticle is the outermost layer of your hair shaft that’s arranged like shingles on a roof.

When the cuticle is open, your hair is hard to manage and can frizz badly. It will also look dull and will have split ends.

What the protein in shampoo does is it coats your hair cuticle, keeping it smooth and protecting your hair strands from damage.

If your hair cuticle is broken, protein treatment can also help fill the gaps, strengthening the hair.

Improves Shine

Protein shampoo works great for restoring your hair’s natural shine and bounce.

That’s because it flattens your hair cuticle, giving each strand a smoother appearance and helping the hair retain more of its natural oils and moisture.


When your hair cuticle is open, your hair can absorb moisture from the environment creating fizz.

Your hair will also have a rough texture and might be difficult to manage as the cuticles keep “snagging” on each other.

Using protein shampoo regularly keeps your cuticles smooth, making your hair softer and easier to comb.

When Is It Better to Avoid Protein Shampoo?

Protein shampoo offers various benefits for damaged hair, but using more protein shampoo isn’t always the solution.

That’s because there’s such a thing as too much protein for your hair, and this can cause the same problems you’re trying to fix.

Therefore, the rule of thumb is to avoid protein shampoo if you don’t notice any improvements after frequent use or if the condition of your hair worsens.

You should also avoid protein shampoo that has harsh cleansers or sulfates as they can dry your scalp and hair.

How to Tell You Have Too Much Protein in Your Hair?

Protein is marketed as a beneficial hair care ingredient, so it’s tempting to use more of it.

However, it’s essential that you recognize when your hair has had too much protein and avoid excessive use of protein shampoo.

Even though some shampoo products may not be labeled as “protein shampoo,” they might contain ingredients such as hydrolyzed protein, silk protein, keratin, and other types of protein, so double-check the information on the label.

Generally, the tell-tale signs of too much protein in your hair include:

  • Split strands
  • Hair that feels limp and has no life
  • Brittleness
  • Breakage
  • More shedding than usual

If you notice these signs and the only thing that has changed in your hair care routine is the addition of protein shampoo, then you’ll do well to suspect protein build-up. 

To fix the issue, avoid using protein shampoo for a while and use clarifying shampoo instead.

You can also get a trim to remove split ends and refrain from any aggressive handling of your hair until it’s back to its natural, healthy state.

Disclaimer: This site is not intended to provide professional or medical advice. All of the content on LovedByCurls.com is for informational purposes only. All advice should be followed at your own discretion. Ingredients may change at any time so always check the product label before using. Check our full disclaimer policy here.


Photo of author

Dee Poulsen

Dee has been following the Curly Girl Method for over four years and is our in-house Curly Girl expert. She has a keen interest in natural haircare and has tried and tested her share of CGM products. She has a photographic memory of most sulfate and silicone-free hair products available on the high street and she's always happy to recommend you her favorites.