[fareloz]

1. https://www.youtube.com/watch?v=NjrRxDr30gw

2. Yes, companies always do this. Let’s take a look at classic Head & Shoulders shampoo:

INCI: Aqua, Sodium Laureth Sulfate, Sodium Xylenesulfonate, Cocamide MEA, Cocamidopropyl Betaine, Sodium Chloride, Sodium Citrate, Piroctone Olamine, Parfum, Citric Acid, Glycerin, Sodium Benzoate, Sodium Salicylate, Limonene, Polyquaternium-10, Guar Hydroxypropyltrimonium Chloride, Linalool, Sodium Hydroxide, Citronellol, Propylene Glycol, Menthol, Verbena Officinalis Leaf Extract, Citrus Grandis Fruit Extract, Citrus Aurantium Bergamia Fruit Extract, Triacetin, Melissa Officinalis Leaf Extract, CI 17200, CI 19140

Sodium Laureth Sulfate - anionic

Sodium Xylenesulfonate - anionic

Cocamide MEA - non-ionic

Cocamidopropyl Betaine - amphoteric

[fareloz]

UPDATE:

It appeared the problem is water. Distilled water apparently is not the same as deionized water. Due to metal ions in water the copper part of Copper PCA was replaced with these free ions. Then copper ions oxidized. The solution was to replace the water source to have deionized water. The good source is water after reverse osmosis filter without remineralization step.

[fareloz]

I suspect your problem is not about thickness of the product, but maybe the soapiness of the emulsifier. Olivem 1000 is known to give the “soaping” effect (when you rub it, it gives you white cast for quite some time and you can’t rub it in for a while), especially in a combination with gums. If so, you can try switching to other self-thickening emulsifier

[fareloz]

Check what commercial hair oils contain to make them light - caprylic capric triglycerides, carbonates, volatile silicones.

But the supplement itself may have a very sticky base.

[fareloz]

Maybe I am wrong, but buffer solution to me is not just some base in water, but also a corresponding acid. E.g. citrate buffer is Sodium Citrate + Citric acid + Water.

Anyway when you add Salicylic acid to sodium citrate solution you get this:

Sodium Citrate + Water + Salicylic Acid -> Sodium Salicylate + Sodium Citrate + Salicylic Acid + Citric Acid + Water

Basically depending on pH, part of Sodium Citrate will swap Citrate with Salicylic Acid and form soluble in water Sodium Salicylate + Citric Acid.

pH stability for salicylic acid is from 3-4

It is not a stability pH. Salicylic acid in skincare is stable under any pH. It is the lowest pH you can reach in skincare products without being regulated and without precipitation in water-containing solutions.

is salicylic acid will be affected when added to a solution with a pH of 7 or 9 or buffer solution of sodium citrate?

Not sure what do you mean by this. Any acid is affected by rising the pH. The higher pH - the less acid in free form. In your example some of the acid becomes Sodium Salicylate. And that’s fine.

Please I need your answer.

I would suggest searching the forum because questions about Salicylic Acid were asked many times (including from myself haha)

[fareloz]

Such products are not dissolved AA, but a dispersion of very fine AA in the base.

[fareloz]

It is stearic acid and cetyl alcohol, you have too much of them

[fareloz]

Ethylated ascorbic acid is known as the most stable water-soluble derivative.

• This reply was modified 4 weeks ago by  fareloz.

[fareloz]

I have checked several shampoos with clarifying title and they are all just regular sulfate shampoos

[fareloz]

Reduce Propylene Glycol to 5%

[fareloz]

This is almost a typical formula of a hand sanitizer (although most companies use carbomer as it is cheaper than Sepimax Zen). And sanitizers kill bacteria, right? So why do you need preservative for something that kills bacteria itself?

[fareloz]

The 500 Dalton Rule suggests that in order for a molecule to penetrate the skin barrier, its molecular weight must be less than 500 Daltons. All HA forms, even ultra small, are much bigger than 500 Daltons.

Also, the smaller HA ingredient - the less potent it is in terms of binding water. If you need a good hydration - use Glycerin.

[fareloz]

And what are the myths? The title is not related to actual posts at all. It feels like another ad of your business.

[fareloz]

Disclaimer: not a chemist here

pKa of an acid is pH value when half of the acid is still an acid and half is “neutralized” to conjugated base. For example if we take lactic acid, it’s pKa is 3.86. So if we take pure lactic acid solution and adjust it’s pH with NaOH to value 3.86 that will mean we have half of original lactic acid and half converted to Sodium Lactate.

Now when we talk about pKa of combined solution I don’t completely understand what this should mean and moreover what application it could have. Thinking logically we can extend pKa definition and say that pKa of combined acids solution is the pH value when half of combined solution is “neutralized”.

The problem here is it doesn’t mean that each specific acid is also half-neutralized under this value. In case of a mix of very strong acid and some weak acid it means strong acid will be neutralized almost completely with part of the weak acid.

Anyway, if we agree on definition above. I think pKa of combined solution depends on pKa of each acid adjusted by it’s concentration. I don’t think there is a trivial formula especially if the acids can interact affecting their individual pKa values.

Still I’m wondering how you want to use this measure…

[fareloz]

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[fareloz]

Is it the ph of the final formulation or only after adding sodium citrate.

The final pH of the solution. The lower pH - the more acid inside.

And what will I get in the final formulation

As I said you get a mix of original Sodium Citrate, Sodium Salicylate, Citric acid and Salicylic Acid.

The lower pH - the more SA in the solution. But the lower pH - harder to keep it dissolved. If you use only water and Sodium Citrate I don’t think you can get 2% of SA soluble in water under pH 3.0 (but if you raise it to 4.0 most of SA becomes Sodium Salicylate and it is soluble in water)

[fareloz]

Not sure what I can say more here. In products like Skinoren and other similar where AA percentage is 10%+ the acid is not dissolved in some base. Instead a very tiny powder of AA dispersed in the base. The powder is so fine. so tiny and dispersed so evenly that you can’t notice with your eyes and feel with your fingers that it is not dissolved.

[fareloz]

THD is oil soluble while OP asked for a derivative for aqueous formula

[fareloz]

You still don’t provide the use except of this characteristic. Is it just for labeling?

[fareloz]

Please create a separate thread instead of hijacking others question. Because: it is the rule of the forum and more people will see it.

[fareloz]

Of course there is a very popular way - injections.

In terms of skincare - you are not allowed to “penetrate deep”. Skincare is not a drug, it should stay at upper layers of the skin

• This reply was modified 1 month ago by  fareloz.

[fareloz]

I still don’t see the actual application of the value you are trying to get. Maybe you just want a characteristic which is just meaningless and no need to bother with. What you are trying to achieve with this number, what are you going to use it for?

[fareloz]

Yes, you should use a preservative.

And be aware that high polysorbate content gives unpleasant soapy feel on the skin

[fareloz]

The rule is simple - you list ingredients you put, not the outcome of their reaction. E.g. if you put Salicylic acid and NaOH - you list them, you don’t list their product of reaction Sodium Salicylate.

Same here. If you put CCT - you list it.

[fareloz]

It is stated in the comments - iron ions from bentonite, salicylic acid reacts with iron and creates this purple color.

If you get same result without bentonite that most likely you have water not deionized enough