D I Why?

I’ve been working on a DIY beta hydroxy solution that doesn’t contain any alcohol, and I pestered the chemist over at The Personal Formulator about solubility, and they were pretty informative:

Salicylic acid is only slightly soluble in water, one gram dissolves in 460mL water. To incorporate salicylic acid to a formulation, the following methods can be used:

1) it can be added to the oil phase of the emulsion and heated to 80-85C

2) it can be added to a water phase containing sodium phosphate, borax, alkali acetates or citrates to increase its solubility in water

3) it can be combined with a glycol, such as propylene glycol

Since I’m not gung-ho about using borax, glycols or any other unnecessary chemicals, I went ahead and tried to dissolve it in oil alone. However, the crystals seem to re-crystalize once the oil returns to room temperature. I’ve been shaking the solution vigorously and applying it anyway, and I haven’t had any problems — but I’m just not convinced it works well.

Blast it, I wish I knew more about solubility and other basic chemistry concepts! Next time, I’ll be trying to add it to a lecithin-emulsified solution to see if that helps. If any other skincare gurus have ideas, please share them!

2 Replies to “D I Why?”

  1. Try throwing it into a blender! I was able to make a smooth cleanser (with solid cetearul alcohol flakes) by blending it. It stayed mostly smooth.

  2. @Nimue — you know, I used a hand mixer when I originally created it, and I’ve mixed it significantly since. But it’s not an issue of just blending — the salicylic acid is only *slightly* oil-soluble, and I think it has a tendency to re-crystalize at lower temperatures.

    I suppose I could keep re-heating the mixture every few days, but that’s a pain in the ass and I don’t want to cook out all the benefits of my cold-pressed, unrefined oils!

    I’m sure there’s some creepy chemical I could add that would hinder the re-crystalization process. I just have to figure out what that is, and whether it’s worth it to include! Sigh. Wishing I’d taken chemistry back in high school or college — how did I manage to squeak around that?

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