Struggling to get ascorbic acid to dissolve in C/E/ferulic acid serum
First of all, yes, I know vitamin C is unstable and hard to formulate with and I should just buy one off Amazon… but I’m not gonna listen to that advice 😛
So, I’ve been trying to make a C/E/ferulic acid serum based off of Lotioncrafter’s formula. I upped the ascorbic acid from 15% to 20% and removed 5% from the water. I also removed the panthenol and upped the water accordingly. And I’m using NaOH instead of TEA.
Every time I add the ascorbic acid, I’m unable to get it to dissolve. The solution is full of white flakes. I test the pH and it’s about 4.5 before adding any NaOH, so clearly, there’s a lot less than 20% ascorbic acid in solution. I did an experiment: 20% ascorbic acid, 20% ethoxydiglycol, 10% propylene glycol, and 50% water. Again, it didn’t fully dissolve, and the pH was much higher than I’d expect. I did another experiment: 20% ascorbic acid, only 10% ethoxydiglycol, 70% water. Voila: a crystal-clear solution.
I looked up the solubility of ascorbic acid and found that it’s 33%/wt in water, and only about 5% in glycols. This meshes with the results of my experiments. But one member posted here advising another member to avoid using water at all and make a serum using only (I think 15%?) ascorbic acid and propylene glycol. They claimed that ascorbic acid can dissolve in propylene glycol at up to 17% (uh, citation needed…).
My question is: how on earth are you all (and the brains behind the patented C/E/F formula) managing to dissolve 20% ascorbic acid in a serum that has less than 50% water (or even 0% water) when it seems to require much more water than that?
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