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Neutralization of Lactic and Glycolic Acid: NaOH & L-arginine
Hi folks,
What’s the difference in terms of the impact on formula when I use NaOH versus L-arginine to neutralize acids? Besides the cost
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From a chemical reaction standpoint, does the neutralizing agent bring to the formula any “features”? Or the only impact here is pH level?
Did you have the experience to use them interchangeably?
Thank you!
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2 Replies
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Without digging too much into this, the reaction with NaOH and Glycolic Acid is irreversible. You’re lowering the pH by turning Glycolic Acid into Sodium Glycolate, irreversibly. Whether this affects efficacy or not I have no idea. My understanding is that free acids are more effective for exfoliation and have better skin penetration (due to less charge), but somebody mentioned here that there were findings that, at least with Salicylic Acid, the Sodium salt was just as effective even above the traditionally recommended 3.5pH.
With L-Arginine, you have a zwitterionic compound that will get protonated or deprotonated at different pH and the reaction is reversible.
Maybe someone has more specific knowledge as to the benefits of using one or the other in cosmetics.
Another thing to consider is the interaction of electrolytes in your formula. In case you’re using a polymer or emulsifier.
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@letsalcido Thank you! Will research further
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