Wednesday, August 17, 2011

Mysteries of Hydrolyzed Proteins

Updated: October 2017

I have been researching various proteins used in hair products. Claims that this or that protein are high or low molecular weight and therefore good for this or that fell short of an adequate explanation. And some people can use one type of protein, but not another. Some proteins are lauded as being good for certain hair concerns. Okay, why?

The weight of the protein does play a role, and it makes sense if you compare proteins. I converted all weights to the unit “Daltons.” Smaller numbers are easier to deal with, reducing them to Kilodaltons gave some numbers which seemed a bit misleading.

Hydrolyzed Protein Source
Weight in Daltons 
©Science-y Hair Blog 2017

Amino Acids
Less than 200 (usually)
Human hair keratin
Wheat (low molecular weight)
1000-10,000 (depends on the supplier)
1500 (approximately)
1000 (approximately)
1000 (approximately)
1000 (approximately)
1000 (approximately)
Sweet almond
3000 (approximately)
Gelatin (partially hydrolyzed collagen)
60,000 – 200,000 (from a variety of sources)
Each hydrolyzed protein may have amino acids and peptides in the solution as well (smaller molecules).
My sources are varied and so some are showing a range, including peptides (very small “protein” fragments) some show only an average. You can see that some proteins have a broader range of “protein sizes” which refers more to the methods used to identify the protein’s constituents and what I could find reported for that protein.

What is means for your hair: Low-weight hydrolyzed “proteins” are less than 1000 daltons. They’re not whole proteins anymore! Very small molecules (200 to 500 daltons) can penetrate the hair beyond the cuticle. Any and all of these proteins may contain smaller constituents that may penetrate. Penetrating into the hair can help improve elasticity of hair and moisturize deeply.

“Heavy” weights greater than 10,000 (or 80,000 depending on which source you consult) daltons are thought to be good film-formers for shine, body, helping fill in porosities in the cuticle. They are acting at the cuticle, forming a moisture-holding, protective coating and also having the potential to improve hair’s elasticity and strength. 

Medium weight protein hydrolysates (1000 to 5000 daltons) are substantive to hair (bond to hair, don’t rinse off readily). This helps reduce friction (tangling, difficulty combing) which ultimately reduces hair breakage. 

If you want a maximum protein boost, choose a mixture of proteins.

If your hair reacts badly to, say, hydrolyzed rice or quinoa protein but not to keratin, you may have your answer – the hydrolyzed rice or quinoa is forming a film on your hair, first and foremost whereas some of the keratin is also penetrating the deeper cuticle layers and possibly into the hair fiber.

Some hair will respond well to only certain proteins, or only in certain amounts. Light and medium weight proteins help keep hair hydrated by preserving water in and around the hair. Heavy-weight proteins help keep hair hydrated also by forming an invisible film (like a "glaze") over your hair.
There is a post here about the amino acid content of some proteins that further explains why some proteins may work better than others, but for a different reason.

Damaged (porous) hair may appreciate a broad range of proteins, amino acids and peptides to fill in the gaps of damaged cuticles, moisturize, and bond to the hair for ease of combing.

Proteins (top molecules) heated in an acid,
in the presence of water breaking into smaller "pieces"
thus a hydrolyzed protein.
Image from:
Proteins are used as humectants in cosmetics. But they're not humectants like glycerin or sorbitol or propylene glycol which are more "sugary" in nature. In fact - I think a food analogy is good here. If you put some wet brown sugar and some raw egg white on a plate and wait to see which evaporates first - the sugar dries faster. The proteins in the egg white do not release their water as easily. And as you may know - raw egg white dries to a very stiff film. I'm not advocating putting raw eggs in your hair. The proteins are too large to be useful. But you get the idea.

Hydrolyzed proteins in your hair products do the same thing - as humectants they attract and hold water and as protein-based humectants they lose that water slowly. Unlike glycerin or sorbitol or propylene glycol. Because water is what keeps hair hydrated and well-hydrated hair is strong and flexible, this is a wonderful benefit! Proteins or amino acids are ideal for silky or soft hair which is weighed down easily by oils and conditioners. Or for hair that snaps when you run your fingers through it.

There is a list of protein-containing shampoos and conditioners in the "Products By Category" page on this blog.


  1. I'm confused: you have jojoba on here. But isn't jojoba usually the OIL of the jojoba plant ( And not a protein?

    When a commercial product says "jojoba extract" does that mean the oil? Or the protein?

  2. Thanks for pointing that out, hydrolyzed jojoba protein is a completely separate product from the oil (or rather, the wax) which can be added to shampoos and conditioners as a film-forming moisturizer.
    Jojoba extract could mean almost anything from roots to shoots - jojoba seed extract would be the "oil." Ah, the mysteries of labeling.

  3. Thank you for your blog! About the heavier proteins that form a film: do they readily rinse off?

    I also had a question about hair being sensitive to protein. I recently tried a new shampoo and conditioner, both of which have protein. The conditioner (Andalou Sweet Orange and Argan) lists soy milk as the fifth ingredient. After using it, my hair felt dry, wiry, and sticky. I'm assuming this is the soy protein. The shampoo (Griffin Remedy Volumizing) doesn't list specific proteins but simply has "vegetable proteins." Ever since using these products, my hair has been strawlike and does not want to hydrate. Do I just have to wait for the proteins to wear off through friction?

    1. Hello Crazycarholic,
      It's frustrating that Andalou (conditioner) lists "soy milk" as an ingredient. If it really is soy milk, then the proteins are not hydrolyzed proteins and it's difficult to predict how that ingredient is behaving in your hair. If it really is hydrolyzed soy protein (and they just thought that sounded too "chemical" for a "natural" product), then yes - your hair might be reacting badly to a hydrolyzed soy protein ingredient. But we can't make that conclusion because we don't really know what is in there. The ingredients list does not suggest a conditioner with a lot of "slip" - butters like cocoa butter and shea butter are great but once dry they're not good for reducing friction. The conditioning ingredient (Stearylkonium Chloride) is just pretty good for lubrication. It's not great, it's actually kind of wimpy - good for a lightweight cream rinse. That could be making your hair feel worse too.

      Your shampoo listing vegetable proteins should say "hydrolyzed vegetable proteins" - but they probably are hydrolyzed and those tend to be larger proteins. That might be a problem for regular use but okay occasionally.

      Proteins like that (larger ones) do tend to "wear off" with regular wash cycles.

      You can address the strawlike feeling you have right now by using oils and conditioners - add about 1/4 to 1/2 as much oil to your conditioner as you use conditioner (25:75 or 50:50 oil:conditioner) and use that for a rinse-out conditioner (thoroughly massage it into your hair without creating tangles and leave it on for a few minutes) to soften your hair and add a lot of slip. Proteins tend to add stiffness - so oil and conditioner helps balance that by adding softness and flexibility.

      Whenever you use protein - keep an eye out for that dry, wiry, sticky feeling and be sure to use oil added to conditioner or more intense conditioners to balance out protein's support and stiffness with the softness and flexibility of those emollient ingredients. Use butters alone or in products in moderation - they may contribute to that sticky feeling in your hair.

  4. Hi, thank you so much for this wonderful blog, it has really helped me over the past couple of years as a source of information for ingredients. I have been making my own products for the past 2 years as my hair type is a little odd and store bought products tend to make it freak out one way or another.

    I have a bit of a problem though that I am hoping you can help me with.I'm sorry if this is a bit long winded. It has been driving me a bit crazy for the past 2 years now. I used to straighten my hair everyday since I was 15(I am now 31) and I dyed my hair with henna. Naturally it was in a bad state, so when I started making my own products I grew it out and it looks so much better now. It took me 2 years but now I am back to my natural colour(no greys yay!) which is a dark blonde. My hair is super thick, but a mix of super fine and medium hairs, and I have around 5% super coarse hairs that live mostly on my crown area. My hair is around a 2A, but these coarse hairs are very wavy and sometimes even coily. I don't know if I have always had these hairs due to straightening from a young age but I suspect so.

    The problem is, they will not behave whatever I do to them. I think that they may be low porosity even though they are really coarse and coily as they do not like high dalton proteins at all. Wheat and Oat protein cause them to get very stiff and even more coily and they will stick up all over my head, where as the rest of my hair can handle those proteins reasonably well and my hair gets smoother, so it can be quite the contrast and I look very unkempt. At the time I figured they were damaged, but most of them are from the root to the top of my ears and then they sort of settle down, so I now think it is low porosity. I am wondering if I should try silk amino acids? I have the powder version but I have never used it in hair products(mostly creams and lotions). What happens if you use silk protein often? Will it cause the hair to become stiff like film formers, or will it just hydrate? I haven't used any protein on my hair for at least 6 months now. It doesn't feel stetchey or over moisturised but it can sometimes feel a bit dry and tangley, especially around the canopy.

    I should mention that when I wash my hair, these particular sections with the coils become very tangled, and stick together almost like velcro. They feel dry even when they are wet and I have to apply a lot of conditioner and water before I can detangle them. This only happens in the 2 sections on my head where the coarse coils are.

    I am also wondering if perhaps I should stop using coconut oil in my conditioners. My conditioners are made with btms 25, cetrimonium chloride, bamboo and rhodiola extract with glycerin, coconut oil and either avocado, olive or argan oil. Shampoos are made with a combo of sci, dls and coco betaine. Both contain panthenol. I do not use silicones as it makes my hair dry and my ends tangle. I find that the squish to condish method really helps hydrate my hair, which also leads me to believe that I have low porosity. But these darn coils do not want to be contained... what could it be? It is so frustrating to have 3 types of hair on my head. It's like 3 siblings that do not want to get along lol!

    I would be ever so grateful if you could perhaps suggest an oil to use in my conditioner. My hair handles heavy oils very well in products, but not so much once it is dry. Lighter oils work the best for me on dry hair. I was also wondering what your thoughts are on moringa oil if you have any? I have read it is similar to olive oil(which my hair loves) but lighter and it also has behenic acid which is apparently quite good for the hair.

    Anyway I am really sorry for the long winded post and I really appreciate if you get the time to help me with this problem. I understand that you must be mega busy. Thank you so much for your wonderful blog. It has become one of my favourite places for hair related info :) And merry xmas! It's not far away now!

    Kind regards,


    1. Hello Kneeley,

      Silk protein tends to soften hair, you probably won't over-do it with silk protein, but keep it at about 0.5% - because it's a powder, it's concentrated. If that's fine, you can try adding more. But you can also end up with overly-soft hair from using protein, watch out for that result too.

      Your coarse hairs may have some kinking in them. If you have whole sections like that, they might benefit from some avocado oil or olive oil smoothed over them until the hairs feel smooth and flexible, about 6-8 hours before washing.
      Coconut oil can make hair stiff and inflexible - for some people's hair. It's a good hypothesis to test out - whether those coarse hairs have a dislike for coconut oil - by leaving it out of your next batch of conditioner. Those hairs might be picking up some excess rigidity from the coconut oil.

      I do not like avocado oil in conditioner -it seems to take away the "slip." But I love avocado oil in dry hair! I really like a combination grapeseed oil and babassu in my conditioner because they're light. For heavier oils - argan and olive might make a nice combination from the oils you mentioned. I haven't used bamboo extract - but assuming it has high silica content, I wonder if that might also be adding some rigidity.
      Moringa oil looks like a very good oil for a conditioner too - like olive oil but less heavy/greasy would be quite nice.
      Good luck with your formulating! Best wishes - W

    2. Hi thank you so much for the reply! I really appreciate it!

      I have started oil treatments again(with olive oil and essential oils) since posting this comment and it has done wonders for when I wash my hair. My coily hair sections no longer tangle after rinsing out the shampoo. They do still like to stick out but not quite as much.

      I have also made my silk conditioner with olive oil and it is very nice. I left out the coconut oil so we will see how it goes.

      I must admit that avocado oil is a bit rubbish in conditioners. I didn't really put 2 and 2 together until you said. I usually make it for my partner who has super fine, pin straight hair and he likes it because it doesn't weigh his hair down, but I find it doesn't have a lot of slip for me. I will definitely try out moringa and babassu oil next time though! I've been curious about trying new oils, among other things! It's an expensive hobby!

      I'm not sure about bamboo personally. It is a fairly recent addition to my formulas and I really quite like it. I haven't seen much change in the coily hairs when using it or not, although afaik it is a film former and it certainly does add some shine and slip. I know a few months back I did a test over a month with products containing bamboo and without and I definitely preferred the bamboo as my hair seemed to be less fluffy than without. I should maybe try another test with different oils and see what happens :)

      Thanks again for your help. I'll update after a few weeks of testing as it will likely help someone else with the same problem.

      I hope you have a lovely xmas :)

      Kind regards,


    3. Glad to hear you're having some success! I have recently read the same thing about bamboo extract - adding some weight and hydration. Sounds like a promising ingredient.

  5. As always, thank you for your wonderful blog! And a happy new year to you (although belated). I do have a question for you concerning protein and breakage. My hair is a "type 4" texture that is a bit over moisturized, a double edged sword bc while it does not break when it is dry (yay!). I find little wisps of hair in my hand when I apply produc/when it is wet (of all times!). To remedy the problem, I switched from Aphogee 2 Min to Colorful's Neutral Protein Filler as it seemed like a stronger more complete solution/alternative. I felt my hair react to the protein, as I spritzed it in my hair. However, I still found quite a few wisps of broken hair (not shed hair) in my hand. To be honest, I'm at my wits end - I've even trimmed my hair this past December. My hair was doing so well and now? Well... *shrugs* if you have any suggestions, that would be wonderful!

    1. Hello Ivy,
      I love Neutral Protein Filler, it's a great product. If you're feeling a beneficial effect from using that and it's beneficial every time, then there's something else that needs attention. It's normal for hair to be more fragile when it's wet.
      Handling of wet hair is different for everybody. Some people are able to get their hair well-saturated and heavy and it all clings together and I think that's ideal. Often you need a conditioner that's kind of thick or grippy to pull hairs together like that. The more individual hairs get free, the easier it is for them to break.
      - Using oil treatments before washing - for several hours at least with a penetrating oil when you have the time (coconut, avocado, olive, sunflower) can add flexibility and lubrication and that might prevent breakage. You may already be doing that, I'm just brainstorming.
      - Do you deep condition? Does it help? Or does the protein help more? If the protein helps more, maybe you could do a 1-inch strand test with a stronger protein product like Aphogee 2-Step, or, to play it safer, try a different (and large) protein like the quinoa and keratin in Ion Reconstructor.
      - Have you been using protein every wash day? Maybe your hair needs a break from protein.
      - Have you changed detangling tools?
      - Is your water supply the same - did you move, is there a drought - those things can make a big difference.
      - Do you have hard water? I have a post for hard water problems:
      That's all I can think of at the moment. I hope you can find a solution! W

  6. Hi WS,
    May you add rice protein to your list. What's the weight? moisture level? Is it a small, medium, or large protein? Moreover, is rice water a protein as info reports it contains inositol? If so, is it a small, medium or large protein? Thanks so much for your help!

    1. Added. Rice water - as in fermented rice water? That will contain high molecular weight proteins.

    2. Has anyone had luck finding sellers of hydrolyzed proteins under 500 dalton's? So far I have checked lotion crafter and have rephrased my Google searches countless times, but without any luck.

      Wendy do you know where we can purchase hydrolyzed proteins 500 Dalton's and smaller?

    3. Just about any amino acid or animo acid blend should fit your requirement. I think Lotioncrafter sells VegeKeratin, which is an amino acid blend. But "keratin amino acids" or "oat amino acids" would be low enough molecular weight. Because amino acids are protein sub-units, they're small and low-molecular weight. Searching that way (for amino acids), you should be able to find a number of suppliers. Best wishes - Wendy