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What should be the ph value of rinse out hair conditioner, ideally?
I was wondering what the ph of rinse out hair conditioners should be. Should conditioners be more acidic than shampoos? Finding some conflicting information online on this, so I’m really curious.
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17 Replies
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The more acidic (lower pH) your conditioner, the less adsorption happens due to isoelectric effects. Instead, the hydrophobic effect is more important. As you increase pH, you increase bonding sites on the hair fiber thus increasing the amount of cationic that will stay on the hair.
So, the answer is it depends on what conditioning agents you are using. If you are relying on cationic surfactants, a higher pH is better. If you are using longer chain conditioning agents (say Stearyl vs Cetyl) you’ll get more adsorption as a lower pH.
You can read all about how things stick to hair in this article.
https://www.evernote.com/shard/s1/sh/ed523436-1531-466d-9153-d2bac9293f9f/e8f6f08010f30e21b56ef091ef4536de -
wow thanks Perry
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Well, a higher pH may damage the hair.
if you are in the range of the scalp-hair pH, in my opinion, is a better choice. -
I did a little searching and couldn’t find any indication that a pH of 6 was more damaging than a pH of 3. I think the concern of hair damage is when you get up to high alkaline pHs.
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I was talking about more pH 8+
PH 6-7 should be good. -
It would be interesting to see a study where someone compared the damage to hair over a pH range from 1 - 14
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Thanks so much for the answer, Perry! And for sharing the article!
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“It would be interesting to see a study where someone compared the damage to hair over a pH range from 1 - 14”
I’m not sure if you are being sarcastic or not, but why should be a study like that?
Who is going to put anything at extreem pH on their head?
Also there is no such thing, study on hair only? Always it is considered hair and scalp. -
No, it wasn’t meant to be sarcastic.
No one is going to put those pH extremes on their head.
When we do research on hair it is actually done on just hair. Specifically, tresses which are made from human hair. If you want to see the pH effect on hair you could take a number of tresses, expose them to solutions with a range of pH, then examine the damage effects of pH.
Of course, this would mostly be of academic interest but it would still be interesting know. These are the types of experiments we do in the lab to learn general principles about how the world works.
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Perry said:The more acidic (lower pH) your conditioner, the less adsorption happens due to isoelectric effects. Instead, the hydrophobic effect is more important. As you increase pH, you increase bonding sites on the hair fiber thus increasing the amount of cationic that will stay on the hair.
So, the answer is it depends on what conditioning agents you are using. If you are relying on cationic surfactants, a higher pH is better. If you are using longer chain conditioning agents (say Stearyl vs Cetyl) you’ll get more adsorption as a lower pH.
You can read all about how things stick to hair in this article.
https://www.evernote.com/shard/s1/sh/ed523436-1531-466d-9153-d2bac9293f9f/e8f6f08010f30e21b56ef091ef4536de @perr@Perry in this study they compared deposition at pH 3.6 vs 6.9. as at pH 3.6 hair has almost no negative charge, the deposition of cationic at pH 6.9 would be higher.
What about pH 4.5 vs 6.9 for a conditioner with 1% BTMC+2% fatty alcohol?
Now hair would have negative charge when applying both of these conditioners. So would BTMC deposit more at pH 6.9 compared to pH 4.5 too?
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I’ve seen conditioners from major cosmetic companies with pH 3-4.
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@Abdullah - Ultimately, if you want to know if something is more/less conditioning at a certain pH, you have to make the batch and test the product. These are complicated systems and simple heuristics like more deposition = more conditioning just do not always hold up. The paper talks about two mechanisms by which an ingredient sticks to hair (electrostatic and hydrophobic interactions). Which one is more important under which conditions is not easily predictable with any system.
And how deposition is related to conditioning is also not easily determined without actually conducting a test. As @PhilGeis says, most major companies have landed on creating conditioners in the range of pH 3-4. This has worked historically so companies stick with it. They don’t spend a lot of resources trying to find out exactly why something works or the mechanisms behind them. Academic questions rarely get money spent on them when we’re talking about industrial chemistry.
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PhilGeis said:I’ve seen conditioners from major cosmetic companies with pH 3-4.
Did those conditioners have SPDMA and BAPDMA that need low pH to have positive charge or they had BTAC ot other surfactants that don’t need low pH?
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@Perry i agree. We have to test to know which conditioner provides more conditioning.
But to check from which conditioner more cationic surfactant will deposit, i don’t have equipments to analyze the hair and surfactant deposition. So If any study has been done on this, that would help a lot.My particular question is: two conditioners with 1% BTAC+2% fatty alcohol, at pH 4.5 & 6.9, in theory from which one will more cationic surfactant deposit in hair?
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I have some additional thoughts:
Hair prone to tangling tends to detangle much, much easier at lower pH. At a higher pH, the cuticle layer lifts and my hair becomes an impossible to work with mess. I experience this with shampoos that aren’t pH balanced. As soon as I add a conditioner with lower pH I feel a world of a difference. My understanding is that it helps the cuticle layer lay flat thereby reducing the snarling and tangling. I understand that this will result in less conditioner being deposited on hair but what’s the point of it being deposited on my hair if I’m going to end up with a lot of breakage from the tangling?I think as @Perry says the best thing is to try and make something and try it. But I know that most people with curly hair love acidic conditioners because of their detangling abilities.-
Exactly my point of view: I’d rather opt for having my hair easily detangled than a feeling of conditioner deposition and risking breakage.
@Farah your conditioner with low pH could you share the main active combination? And the lower level pH range?
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Hair gets tangled not because of lifted scales, but because we rub hair during the process, especially when trying to dry it with the towel. To prevent that, technique is critical.
Lifting scales make hair prone to scale up due to friction. For that, both lubricants (lile silicones) and cationic molecules (particularly cationic surfactants) are preferred.
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