Usage and Compatibility of Vitamin C, BHA, and Azelaic Acid Serums

Asked by: phoom_au On: July 01, 2013 Product Type: Cosmetics

Question

I have questions regarding the usage and compatibility of Vitamin C, BHA, and Azelaic Acid in my skincare routine:

1. If I use a homemade Vitamin C serum with a concentration of approximately 15% in the morning, will it make my skin photosensitive?
2. After applying the Vitamin C serum, can I layer a cream containing Vitamin B3 and Arbutin over it? I've heard that Vitamin C cannot be mixed with B3 as it reduces B3's effectiveness.
3. I'm considering using BHA 2% + Vitamin C as a serum/toner in the morning and Azelaic Acid at night. Is this routine suitable, or should both BHA and Azelaic Acid be used only at night?

Answer

Hello,

Regarding your follow-up questions about Vitamin C, BHA, and Azelaic Acid:

  • Does 15% homemade Vitamin C serum used in the morning make skin photosensitive?

    • Generally, L-Ascorbic Acid (which is often the type used at high concentrations) does not cause photosensitivity in the same way that exfoliating ingredients thin the skin. However, applying acids to the skin can cause irritation, and sun exposure can increase that irritation. So, while it doesn't make your skin prone to darkening just from light exposure, you should always use sunscreen and avoid intense sun.

  • Can Vitamin C serum be layered with a cream containing B3 and Arbutin?

    • Layering is generally possible. However, when mixing ingredients yourself, controlling the pH to be suitable for both L-Ascorbic Acid (if used) and Vitamin B3 is very challenging. L-Ascorbic Acid typically requires a low pH (around 2.5-3.5), while Vitamin B3 works best at a more neutral pH (around 5-7). Mixing them in the same formula or layering them without the correct pH could make some ingredients less effective or degrade quickly. C7 also mentioned the challenge of maintaining pH and oxidation issues.

  • Using BHA 2% + Vitamin C in the morning and Azelaic Acid at night?

    • Both BHA and Azelaic Acid have exfoliating properties and can increase skin sensitivity to sunlight. As previously advised, Azelaic Acid should be used at night. BHA 2% is also a relatively high concentration and is generally recommended for nighttime use. Using multiple exfoliating ingredients, or using them in the morning, can increase the risk of irritation and photosensitivity.
    • Therefore, it is recommended to use both BHA and Azelaic Acid during your nighttime routine. You might consider alternating them on different nights or focusing on one at a time, especially as a beginner, to see how your skin responds. Using BHA 2% in the morning is not recommended.

Important Note: Regardless of the ingredients you use, applying SPF 50 PA+++ sunscreen daily and avoiding intense sun exposure are crucial, especially when using exfoliating ingredients like BHA and Azelaic Acid, to prevent skin darkening and damage.

Mixing L-Ascorbic Acid in a water base yourself is quite complex regarding stability and pH. It is recommended to thoroughly research homemade Vitamin C formulations before attempting it.

Hope this advice is helpful.

Tags

Azelaic Acid BHA Compatibility Photosensitivity Vitamin C