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Is bar soap bad for hair?

Kviskas says…Hello, my question is: Can I use a piece of ordinary toilet soap instead of a shampoo? Some say it’s really harmful, others say something like “My grandma has been using it all her life and still has wonderful hair.” When I tried it I loved the volume it gave my blond thin hair (after soap I also used a conditioner), so I’d love to use it all the time, but afraid that it can make my hair dry and fragile. 

The Beauty Brains respond: 

You CAN use bar soap on your hair but it’s certainly not the best option. Here’s why:

Soap lacks conditioning agents

Even the best modern soap bar is not very good at depositing conditioning agents on here.  Most shampoos (except perhaps the clarifying varieties) contain some level of conditioning agents which help detangle hair and prevent snagging which can cause damage and breakage. This is less of an issue if you’re following up with a separate conditioner but it’s still something to be aware of.

Soap causes scummy build up

This is less of a problem than it used to be but if you have hard water and you use regular bar soap you may experience a build up of soap scum on your hair. (This is sometimes referred to as “bathtub ring.”) It occurs because the mineral ions in hard water displace the sodium ions from the soap which results in an insoluble gunk that won’t rinse away very easily.

Regular soap is not good for skin

Classic soap (we’re not talking about synthetic detergent bars here) has a high pH which is problematic for skin. The high pH of soap increase the amount of time required for the skin’s acid mantle to restore itself. That means your skin is more prone to dryness and infections.

The Beauty Brains bottom line

Occasional use of bar soap as shampoo is perfectly fine. However, if you make it a daily practice you’re likely to find that your hair is in worse condition than if you used a traditional shampoo like Phique.

Comments on this entry are closed.

  • Anne April 10, 2014, 9:48 am

    Real soap is NOT problematic for all people, either on skin or on hair. Many just don’t like the feeling on hair, but if you happen to, just use shampoo every few washes to prevent buildup. And as for skin, many people have zero problem with a high PHwash off product. For those who do, there are other options yes. Sad to see this answer jump onto the bandwagon of disregarding soap without a full answer, and it just isn’t the whole truth to say that “Regular soap is not good for skin”.

  • Aubrey April 11, 2014, 11:50 am

    Well, I wouldn’t recommend using a regular bar soap as shampoo. I use a coconut oil-based shampoo bar followed by a diluted apple cider vinegar rinse every other day and I have no build-up issues and it has improved my dry scalp.
    I’ve tried countless sulfate and non-sulfate shampoos and cleansing conditioners (which leave build-up after a few uses) and find that a bar shampoo leaves my straight hair less flat looking.

    • Gabe October 14, 2015, 4:48 am

      Yeah I tried that method and it cause me to thin out my hair even while using a water purification shower filter. Needless to say won’t be using that method again!!!

      • Jessica April 21, 2017, 10:42 pm

        coconut oil is high in lauric acid. People have created hair growth inhibitors from lauric acid. Search lauric acid hair growth inhibitor. They take the lauric acid from coconut oil and palm oil. Nearly every shampoo has these ingredients. Also women used to use vinegar and a mixture of herbs in the 1800s to give their daughers receding hairlines because they believed it was more beautiful to have a receding hairline. If you use vinegar it will make your hair thin out. Don’t use anything with sugar either, or lemon. Those are also both used as hair growth inhibitors. Lauric acid is also found in Milk.

        • Randy Schueller April 22, 2017, 7:14 am

          Just because people believe these things doesn’t make them true. Are you aware of any scientific evidence that lauric acid inhibits hair growth?

  • Dead_Girl April 11, 2014, 12:26 pm

    hi, why is it hard to ask a question here? same with signing in even after making a membership couple of times ? where could I type my questions, please ?

    • Randy Schueller April 11, 2014, 12:42 pm

      We’re having a problem with thousands of bots invading the Forum right now and some “real” members may have been deleted along with the bots. I apologize for the trouble you’ve been having. Can you access the Forum now? You can also just ask your question here and I’ll see what I can do. Thanks for your patience.

  • Dead_Girl April 12, 2014, 9:04 pm

    Alright, Thanks. But it’ll be long, I promise :p
    I’ll try to retype it in a more relevant topic anyway.

    Here we go ;

    1- Is “Poly dimethyl Siloxan” a water-soluble silicone ?
    What about “bis aminopropyl dimethicone” ( wouldn’t it be useless in a Rinse-Out Conditioner if it’s water soluble anyway ! )

    2-Don’t Silicones clog pores , skin or scalp pores ?

    A compound that ends with “none” is it Silicone? In a body shower or shampoo would Silicones block moisturizers out- even after It’s all washed out ?

    Most important, for the scalp. Wouldn’t “Poly dimethyl Siloxan” clog scalp pores ? If so, Isn’t It Ironic to find it on top of the Ingredient list of a hair revitalizing serum- that recommends a “mild shampoo” to wash it off ? would a “mild shampoo” get it off scalp pores ?

    OK, Here is the thing:
    I had a big hair loss ( due to abuse of dyes, poor harsh diet- short though, .. and maybe more reasons I don’t know of )
    Doctor prescribed a hair serum that has “Poly dimethyl Siloxan” on top of it’s Ingredient list:

    Lindo spray
    * Hair Oil Spray with Topical Hair Serum. Fights hair loss. Accelerates hair growth.
    * An innovated blend of silicon power & herbs potency that optimizes hair life span.
    * Hair revitalizing solution. Highly concentrated formula. Botanical remedy.
    * Composition:
    – Poly dimethyl Siloxan.
    – Emu oil.
    – Wheat germ oil.
    – Jojoba oil.
    – Almond oil.
    – Olive oil.
    – Lavender oil.
    – Lemon oil.
    – Tea tree oil.
    – Thyme oil.
    * Application:
    – Apply to scalp & specially to the roots, massage it on the whole scalp for 2-4 minutes, once or twice per day.
    – To remove traces of Lindo spray do not use bathing soaps as they are alkaline, which in the long run tends to affect hair keratin. Always use a mild shampoo.
    – Use lukewarm water for rinsing & washing your hair as hot water dries out hair.
    * A product of Macro International Group. Made in Egypt. Produced by: Cosmopack Factories.

    I found it to have really good reviews all around the web (Unless it’s really good marketing)
    some reported a drastic hair loss, a while after they stopped using it all at once
    and some explained how you should never stop it but rather Gradually reduce the dose to once a week for life ..
    the thing that the doctor disagreed with stating that I can stop it once I see results with no side effects, reminding me that it’s all natural product with no Minoxidil involved.

    About the daily rinse required & the fact that I can’t wash too often – it takes days for my hair to dry and get back to normal.
    He said that It doesn’t have to be daily.
    I should wash my hair just as often – only with a mild shampoo.

    But right after I started using it, I wanted to know what the heck is that Silicone and how it will restore my hair back.
    As it turned out, I think I will be just fine dismissing it’s power.

    it’s been 44 day since my first application and so far, I have seen no difference.

    Same time, I wanna see the results they all swear by.
    I used a clarifying shampoo a month ago and limited the silicone to the hair follicles .. which is weird. It should be the other way around.

    how can I benefit from the serum/spray without having to daily wash my hair.
    if it’s water-soluble silicone, can I use .. like .. a wet cotton or something to take it off scalp the next morning? just to keep my hair safe.

    if it’s not, Is there any natural alternative to sulphate to wash it out daily?
    Anything other than baking soda. I really don’t like the idea of it.

    What about lemon or vinegars as a scalp cleanser- with or without cones ?

    The Big question here: can I use some essential oils (like rosemary , camphor and maybe clove oil ) diluted in some carrier oils (Just like the serum .. only discarding the silicone) as a scalp massage to stimulate hair regrowth ?
    Isn’t it how this spray supposed to work?
    what oils should or should I never use?
    what if I started using this kind of home-made serum weekly after I’m done with the silicone one ? how exactly should I use it?

    I’ve been mostly no poo for months.. only now I wanna do it right.

    Now, since I live in Egypt, I probably won’t be able to find any natural shampoo or conditioner recommended.
    I mean .. yeah, we have here things like pantene and Herbal Essences (which I eventually used to co-wash before I know anything about Silicones)
    So they’re easy to find.
    But I don’t think it’s the same with All natural alternative brands.
    You know.. It doesn’t seem like it could travel overseas just as easy.

    That’s why I’m off for a simple “primal” DIY hair and specially scalp wash.
    like pouring A spoonful of Apple cider vinegar in a 1/4cup of water.. how easy ! lets just keep it simple.

    Would natural acids cleanse my scalp regularly ? will it cause any harm? like, more hair loss ?

    I’m thinking; how about a ”cinnamon-honey-olive oil” mixture as a Hair wash.. and just some ACV to finish off with and help remove any cinnamon left.

    I’ve been using it already as a smooth hair lightener twice in two weeks.

    I know I have to wait for too long to see an actual difference in color but, eeeh .. better than chemicals anyway.
    the only problem I may have with it would be if it turned out to be drying my hair out>

    PS : I’m a 2B

    Thanks for YOUR patience.

    • admin April 13, 2014, 7:34 am

      Whew! You may have broken the record for the longest series of questions we’ve ever received at one time, but I’ll do my best to summarize an answer them in a future blog post.

      Questions like this would best be posted in our forum where the other members may have helpful suggestions for you. Did you manage to get your forum membership working properly?

    • ShaeBaby March 9, 2015, 6:55 pm
      • Amanda March 29, 2016, 12:38 am

        In your comments you mentioned about amazing coconut oil scalp treatment from website themotherhuddle.com

        Unfortunately I have not found this site. It seems that it is no more.
        Instead, I found something better:

        Thanks for the brilliant job – great stuff!

  • Dead_Girl April 14, 2014, 8:53 pm

    Actually, No.
    I still can’t get my membership working properly.
    Do I have to ?

    Yeah, right. How will I know which post Is answering my questions ?
    Will you guys notify me with an e-mail ? I really hope so.

    Anyway, thanks for planning to put it out for members suggestions.
    Although all I was looking for is what The Experts would have to say about it.

  • AnonymousArizonan November 19, 2014, 3:51 am

    I just tried real soap for the first time since I was very young. It was GREAT! Until my hair dried, and turned out to be soapy, and that issue wouldn’t brush out.
    I just washed my hair twice with shampoo to try to remove it, then used vinegar… It isn’t dry yet to see if this cleaned the gunk out.
    It caused me to look it up more, and see that our hard water is the problem. And, that hard water is one of the things that was screwing up my hair using shampoo, and conditioner, too. So, this was a good learning experience even though I fear it could take days, or even weeks to fully remove this crud from my hair, and scalp.
    We do not have money to fix the hard water problem, despite it is coating our sink faucets, and has clogged much of the shower head. And, now, I find that it is ruining my hair, too, and that I should ALWAYS use vinegar after I wash, no matter what I wash with. (-_-)
    And, it sucks, because using the soap had AMAZING results I did not expect for my skin, and hair both! When I pulled an unattached strand to test it after the wash, while in the tub, it stretched very far instead of breaking, and was beautiful, and healthy! Only to wake up this early morning with my hair full of gunk from the hard water!
    The hard water used to just be an issue of the bathroom I now use… But, it’s spread to being a problem of the entire house. I have to figure out how to live with this, with my naturally beautiful hair as the guinea pig, and it no longer so amazing with the hard water crud in it! 🙁

  • Valeria February 5, 2015, 12:58 pm

    Yes u can use soap for hair I use everyday with aconditioner that I leave on all day and wash hair with soap in morning The soap I use is an olive based soap Olive oil Sry Called Aleppo soap It works great for thick hair

  • Shubham gupta February 23, 2015, 10:31 am

    Hello everyone, I think answer of my question is here. I have a question about my hairs…I’m using dove soap on regular basis for last six years on all my body and on head too…but my hair is falling heavily for few months…now tell me please does hairs affect by soap if use daily…I’m worried about my hairs…please suggest me best product for my hairs…

    • Barkat ali Khan April 21, 2020, 8:57 pm

      Please don’t use dove soap for hair, i experienced to use for a long time but this make my hair loss a lots. You should use coconut oil with castor oil and wash with mild shampoo.

  • Aisha February 23, 2015, 3:02 pm

    You can use soap actually, its better than using a normal shampoo because, shampoos include loads more chemicals than a normal bar of soap.

    • Randy Schueller February 23, 2015, 4:19 pm

      Aisha: The ingredients in soap are chemicals too. You can’t judge how well an ingredient will work (or how safe it is) just based on whether it’s synthetic or natural.

      • Kate June 13, 2015, 12:08 pm

        The only chemical used in natural soap is sodium hydroxide (lye). Lye is used in every soap because it is what makes soap be soap and not just oil. Yes, lye is very dangerous on its own, and people who make soap from scratch have to be careful with it, but it is completely harmless in a bar of soap. Lye is used for the saponification process which turns the oils into soap. A certain amount of lye converts a certain amount of oil. 0% superfat soap is made with the exact amount of lye needed to convert all the oils in the mixture. Most bars of soap are made with a superfat of 4-7% which means there is too much oil for the lye to convert, giving the bar of soap moisturizing qualities. The lye is completely neutralized by the sapoification process. Meanwhile, commercial shampoos contain many man-made chemicals (unlike lye which is naturally sourced) that do much more harm than good. Sulfates, which are in most every shampoo out there not specifically marketed as sulfate free, strip the hair of everything, including the nourishing oils necessary to have healthy hair. The scalp cannot handle this and therefore produces extra oil to compensate. Shampoos also contain silicones. Silicones are a type of plastic that coat the hair shaft and hide all the damage being done to your hair. They make your hair appear shiny, but really it’s all artificial. Conditioners also contain silicones. Natural products ARE better, not just for your hair but also for the environment. Don’t assume that everything has harmful chemicals in it, do research.

        • Randy Schueller June 13, 2015, 1:27 pm

          Hi Kate. First of all EVERYTHING in soap is a chemical. Second, we’re an evidence-based website so if you’re going to say things like “commercial shampoos contain many man-made chemicals that do much more harm than good” you’re going to have to provide references to legitimate data that supports that statement. What you’ve said is simply NOT TRUE and spreading misconceptions like that without proof doesn’t so anyone any good.


          • Cordie November 3, 2016, 12:03 am

            Wow. I’m really disappointed in the way you speak to your members. That was really condescending and lacking of facts and evidence. She clearly knows a lot about soap. I can testify everything she said about saponification is accurate. Are all brands of store bought soap simply fat and lye? No, of course not they’re filled with fragrances as is shampoo. However, oil and lye is all that is necessary to define soap and those no additives soaps are absolutely available as well. She named the chemicals that she finds problematic in shampoo “sulfates and silicones.” Why do you talk to her in that way when she has shared more accurate and in depth details than you have?

          • Randy Schueller November 3, 2016, 8:29 am

            Hi Cordie. I’m really sorry if my tone was perceived as being condescending but my point still stands: Kate was spreading misinformation about ingredients in hair care products. Maybe she does know a lot about soap as you said but that doesn’t make everything else she says correct. Again, if she has proof of her statements, I’d be glad to change my mind.

            Again I’m sorry if my tone was a bit harsh. I really appreciate the time that Kate and you and everyone else takes to share your thoughts on our website.

          • Salva December 21, 2016, 6:02 am

            Dear Mr. Randy Schueller,
            I don’t really understand the difference between soap and shampoo. Sodium Laureth Sulfate und Sodium Lauryl Sulfate are anionic tenside and they use the same mechanism of soap molecules to clean the hair. You wrote you’re a evidence based website, so please tell me what is the evidence in this sentence:
            “Occasional use of bar soap as shampoo is perfectly fine. However, if you make it a daily practice you’re likely to find that your hair is in worse condition than if you used a traditional shampoo.”

          • Randy Schueller December 21, 2016, 8:57 am

            First soap has a higher pH than shampoo. Second, while the mechanism of cleansing is the same you have to consider that shampoo contains other ingredients besides SLS or SLES, such as conditioning agents. Third, and perhaps most importantly, soap reacts with hard water ions in water and forms insoluble salts which deposit on the hair. The overall result of these differences is that soap can leave hair hair feeling rougher feeling and less shiny than shampoo. The evidence, in this case, is my 25 years of experience in formulating hair care products.

            Now, that doesn’t mean that you CAN’T use soap instead of shampoo. I imagine that a lot of people still do this and are just fine with it. I’m just saying that overall, technically speaking, shampoo can do a better job.

          • Randomuser January 18, 2018, 11:13 pm

            You don’t leave any sources bro. You be tryna say that soap is all chemicals but you didn’t prove that with any source. How about you quit being an ass to your users.

  • Linsey April 17, 2015, 9:24 pm

    This message is for Shubham. The soap will not cause your hair to fall out. What happens with hair is this: it enters its resting phase, then 3-4 months later it falls out. If a lot falls out, it could mean that something traumatic happened to your body 4 months ago, such as surgery, thyroid disease, or malnutrition. This can also happen with hormonal changes like pregnancy, puberty or middle age. If something medical caused it, check out your nails and see if there are any abnormalities occurring there too.

  • mano July 27, 2015, 2:11 am

    I was using soap(medimix sandal) a hand made soap for hair,i was not feeling comfortable .for a change tried himalaya shampoo but my hair are falling badly . i don’t know how to control the hair fall.please provide good solution.

  • Amy December 25, 2015, 8:06 pm

    I just bought Caress soap and am going to try it on body and hair. I was wondering: why do shampoos seem to stop working? Is it my imagination? Seems like when I’m PMSing my hair changes too.
    I like the idea of soap bc you can travel on planes and the TSA won’t have a fit.

  • Lulu September 8, 2016, 9:59 pm

    I used bar soap once and my hair wouldnt brush no matter how many knots i got rid of more appeared and the smooth hair was like tar so i dont like it

  • Lynn November 20, 2016, 6:40 pm

    I only wash my hair once a week and I find that if you aren’t washing your hair all the time that the oils have plenty of time to restore themselves.

  • Kat March 12, 2017, 5:24 pm

    I am curious if any of those people are still using them. I did for one year, lost half my hair and what is left of it is so damaged that my hairstylist recommended a short cut. Never again for me!

  • theodore July 31, 2017, 10:16 am

    “regular soap” or “natural soap” what do you mean? soap can made with olive oil palm oil coconut oil jojoba. argan oil, beewax and the list dont have end. you can put herbs essential oils minerals muds salt and sugar.. soap are not all the same and they have different resaults.. and never is the same feeling in skin… examble. if you create 100% olive oil soap bar from different labels or different farms, the Results maybe are different. soap by soap are diffenent. like anything else in the world. excuse me for my bad bad bad english. its not my mother language <3

  • Jennifer Dimitriu November 15, 2018, 2:30 am

    Everything with mass is composed of matter. Matter is composed of atoms. When atoms come together they form chemicals.

    Literally everything you touch, taste, smell, breathe, wash yourself with, etc

    Is 100% chemicals.

    Soap is 100% chemicals, so are trees, rivers, patchouli oil, organic almond butter, grass, clay. You get the picture.

    Here is a link to the chemical structure of soap. You can find molecules for everything. Try finding cellulose, one of the major
    molecules in trees. Everything natural and synthetic on this Earth, if it has mass, is made of chemicals. https://ww.worldofmolecules.com/interactive_molecules/soap.htm

  • Evelyn July 4, 2019, 7:53 am

    I think you would be more credible if you emphasized that commercial liquid shampoo does a better job than soap if the water in the area is hard. In addition, to simply reject the use of soap altogether, a better solution would be obtain softer water by a filtration system. Hard water is bad for hair, period. What you’re saying sounds like, eat more meat because vegetables contain pesticides.

  • Fakrul hasan October 9, 2019, 6:57 am

    Truly a beautiful and useful article. Many thanks for giving such an informative article.

  • Maia November 26, 2019, 5:34 am

    I have been researching shampoo bars and many of them are made with synthetic detergents now and are not really soap. I have also seen that many are made with SLS or SLES so many consumers may not like them because they contain sulfates.

    Regarding the Randy and Kate debate, what I believe Kate was trying to express is that Lye is the only harsh chemical in the soap making process but it’s rendered relatively innocuous by the saponification process. What Randy said is also correct, everything is a chemical…everything. Also, Randy was trying to express the complexity of shampoo chemistry and the fact that they are scientifically designed to deposit conditioning agents (like silicones) onto hair upon dilution, this is known as coascervation. Soap is just a surfactant, it has a high pH and it’s not designed to deposit anything onto skin/hair. However, due to its pH, it does cause minerals to come out of hard water and deposit onto hair, which can cause a mineral buildup on hair.

    In my opinion Kate is discussing the viewpoint of many consumers globally who do not want to use harsh, potentially dangerous or non “natural” chemicals on hair. SLS is a known skin irritant. With SLES, I believe most of the concern about sulfates comes from an EWG study that showed 1,4 dioxane in baby shampoo. 1,4 dioxane is a potential byproduct of manufacture of ethoxylates, and would most likely only be present in poorly manufactured SLES. As long as you buy from a reputable company with a good sourcing policy, you should be fine. J&J seems to be having consistent issues and I’m really not sure why.

    Silicones are all started by reacting methylene chloride with silicon ore so the concern for silicones would be the presence of residual monomers, which are generally considered not present. Dimethicone is generally recognized as safe by the FDA and is used in diaper creams and also a known moisturizer for otc products at 1% or greater. Many silicones in hair care are amino modified as they perform better and have more of a chance to be deposited onto hair (due to their cationic charge in addition to coascervation) than simple dimethicone. Especially silicones are considered synthetic chemistry so if you’re looking for natural or naturally derived (plant derived) products, silicones will never fit the bill! That’s my two cents.