[em88]

You will loose the anti dandruff effect if you neutralize that much the salicylic acid.
What is the base shampoo pH and viscosity? When you add salicylic acid, it should increase the viscosity of your base shampoo and of course, will lower the pH. 
My suggestions are to add HEC up to 0.5% and change cocamide DEA with TEA since TEA has a higher pH. 
I would not recommend increasing the pH that much, but you can keep adding TEA and pay a lot of attention to the viscosity since it will drop rapidly. 
After that add NaCl (try to do the salt curve). 

[em88]

@Doreen81 No worries mate 

[em88]

What pH are you looking for? Cocamide DEA should already increase the pH and you should not need NaOH.  You don’t have to get a pH 7. 
Most likely by adding NaOH you decrease the viscosity a lot and adding NaCl would not resolve the issue even over 3%.
My suggestion is to remove NaOH.
I did the same shampoo and the result was pH 3.8-4 and viscosity 2000-5000 cP. 

[em88]

@Doreen81, as far as I know, minoxidil is used in lower concentration (up to 10%).

[em88]

Depending on the HPMC type you use, varies the temperature you need to heat the solution/water. Usually I go for a 70-80oC. If you have jelly things floating in the solution than it is undissolved HPMC

[em88]

Awesome! I just wanted to hear again this statement (I was kind of unsure)! Thanks!

[em88]

Did you add salicylic acid?

[em88]

minoxidil is a well established API so the efficiency should be over 25% easily, 60% sounds more right, while 90% seems too much 

[em88]

@Belassi, pH 4.5 isn’t too risky considering the scalp and hair pH is 4.5-5.5? Just asking, don’t get me wrong.
As @DRBOB@VERDIENT.BIZ said, I’d add 0.1%-0.2% Na2 EDTA

[em88]

Thank you for your help.  I hope that everything will go well with this product. 

[em88]

Greetings,
Thank you for your input, very much appreciated. I do have paraben as preservatives.
The current pH of the shampoo is 4.7-4.8 (with 2% TEA) and the viscosity is adjusted at 2000-5000 cP with 1.5% NaCl), while the inspiration shampoo has the pH 5 and the viscosity 1500 cP.

[em88]

Hello,
That is from inspiration product.
The ingredients I am using are: 

Sodium Laureth Sulfate, Cocamidopropyl Betaine, Disodium Laureth Sulfosuccinate, Hydroxyethylcellulose, Butylated Hydroxyanisole, TEA, NaCl

Thank you

[em88]

@DRBOB@VERDIENT.BIZ, I’m adding 1.5% NaCl and I’m getting the viscosity in the range of 2900-4000 cP.
@Belassi, I’ll add the ingredients shortly.

One more question, I was looking the the shampoo that I am trying to make a similar one, and I noticed they have add Sodium Citrate (it seems a lot actually since it is in the top of the ingredient’s list). What is the purpose of it? Adjusting pH or viscosity?
Original shampoo ingredients

Original shampoo ingredients:
Purified water, ammonium lauryl sulfate, sodium laureth sulfate, sodium citrate, cocamidopropyl betaine, lauryl glucoside, PEG-150 pentaerythrityl tetrastearate, coco-glucoside, glyceryl oleate, aleurites moluccana seed oil, zinc PCA, panthenol, rheum palmatum extract, carthamus tinctorius (safflower) flower extract, camellia sinensis leaf extract, edetate disodium

Thank you

[em88]

Is that $12 any good? Just curious.

[em88]

Quick question:
Are there limits in adding NaCl for viscosity adjuster? 
From what I red NaCl at 3.5% will dry the skin and hair. 
I did the salt curve and if I go over 2% (say 2.5%) the viscosity still increases. 

[em88]

Ketoconaole forms clear shampoos, it is not soluble in water.

[em88]

Thank you for your time Belassi.
I red about salts and salt curve that increases the viscosity of shampoos. 
I’m waiting for an other substance that I should add in the shampoo which has a pH 5-6 in 10% water solution and I’m guessing the viscosity should change. 
It will be a “watching and learning” experience. 

[em88]

Belassi Thank you.

[em88]

That is not a problem at all. As stated in our previews conversation, I have only mention where the project is targeted not how it will be described for.
There are lots of plant teas that are targeted for specific diseases, it doesn’t mean they are medicine drugs. Anyway, it would be better to focus more in the technical/chemical issues.

[em88]

Indeed we had a discussion regarding SA
In this case the SA is at 3% which can be considered as cosmetic if specified as rinse of. The original shampoo product i’m trying to make the generic, has the pH 5.15
The shampoo is going to be for psoriasis (and seborrhoeic, dermatitis)
I am currently reading some patents about pH interval for shampoos and it seems that pH 4 is ok for the scalp. 

[em88]

So what should I do? Leave the pH 4? 

[em88]

That is because of the API which is salicylic acid

[em88]

Ok, I tried using NaOH 10% and I added to one test probe ~ 6 % (pH 3.9 -> 5.14)
and to an other test probe ~2 % (pH 5.05 ->5.. The second probe had already TEA which increased pH from 4 to 5.
NaOH decreased the viscosity of the shampoo as well (it seemed that it decreased it a little less than TEA)
Will have to make a few more tests to get a better comparison for TEA and NaOH and determine which one is more suitable since the two tests I did were not similar in the start. 
Anyone else had similar experience with shampoos?

[em88]

Thanks. Will try it! 

[em88]

Thank you very much for your reply! 
I’ve used TEA, and added about 2% to increase the pH from 4 to 5 and wired thing was that it decreased the viscosity of the shampoo a lot.
I was thinking about NaOH as well, but at what molarity should the solution be?