Questions about Liquid LHA 10% Usage, Dilution, and Formulation with Other Acids

Asked by: best_singnontad On: June 22, 2014 Product Type: Cosmetics

Question

I have some questions about using Liquid LHA 10%:

  1. Is it correct that Liquid LHA 10% means 10 grams of Active LHA per 100 grams of product?
  2. If I need 10 grams of Active LHA, do I need to use 100 grams of the Liquid LHA 10% product?
  3. Is it safe to apply the Liquid LHA 10% product directly without dilution? I tried mixing 20 grams with 30 grams of water and applied it, and it didn't feel severely irritating, but I saw some inflammatory acne appear later.
  4. The product page recommends a usage rate of 5-20%. Does this refer to the concentration of the Liquid LHA 10% product in the final formula, or the concentration of Active LHA?
  5. Could the inflammatory acne that appeared after use be a sign of allergy, or is it a normal reaction?
  6. How often and in what method should I use the diluted Liquid LHA? Should I leave it on or rinse it off?
  7. I am considering making a formula with the following ingredients:
    • L-Ascorbic 12%
    • LHA 5% (from 10% liquid)
    • Lactic Acid 3%
    • Glutathione
    • Zinc PCA

      Is this formula safe to use? Will it cause severe irritation due to combining multiple acids like LHA, Lactic Acid, and L-Ascorbic Acid? What pH range would be suitable for this formula to minimize irritation?

Answer

Guidance on using Liquid LHA and incorporating it into formulations

Hello, I understand you have questions regarding the liquid LHA product you purchased. Please allow me to explain point by point:

  • Active LHA Concentration: Your understanding is correct. Liquid LHA 10% means that in 100 grams of the product, there are 10 grams of Active LHA. Therefore, if you purchased 20 grams, it contains 2 grams of Active LHA.

  • Amount Needed for Desired Active LHA: If you need 10 grams of Active LHA, you would need to use 100 grams of the 10% liquid LHA product (since 10% of 100 grams is 10 grams). However, the typical usage rate for Active LHA in cosmetic formulations is around 1-2%. Thus, using the 10% liquid LHA product at a concentration of 10-20% in your formula will result in an Active LHA concentration of 1-2%, which is the recommended rate for exfoliation and wrinkle reduction.

  • Applying Liquid LHA Directly: The 10% liquid LHA product has a relatively high concentration of Active LHA. Applying it directly without dilution can easily cause irritation. Although you may feel it is not severe, everyone's skin responds differently. It is always recommended to dilute it before use. The mixture of 20 grams with 30 grams of water that you made resulted in an Active LHA concentration of approximately 4% (calculated from 2 grams of Active LHA in a total solution of 50 grams), which is still considered quite high.

  • Using at 20% Concentration: As explained above, the recommended usage rate of 5-20% on the sales page refers to the usage rate of the 10% liquid LHA product in your formula, not the Active LHA concentration. Using 20% of the liquid LHA product in your formula will result in an Active LHA concentration of 2%, which is within the recommended range.

  • Inflammatory Acne After Use: The inflammatory acne that appeared may not be a direct allergic reaction but rather a response of the skin to exfoliation and the dissolution of clogged pores. LHA helps to dissolve clogged pores, which can cause existing clogs under the skin that were about to become inflamed to surface more quickly. Additionally, LHA can cause slight irritation, which may worsen the inflammation of existing acne. Leaving it on overnight might also contribute to the symptoms becoming more apparent. If the symptoms are not severe and gradually improve, it might just be a skin adjustment phase. However, if the symptoms worsen, you should stop using it or reduce the concentration.

  • Frequency and Method of Use: You can use the liquid LHA (after dilution) every night. You can apply it and leave it on like a regular moisturizer; there is no need to rinse it off. However, it is crucial to closely monitor your skin's response. If you start experiencing irritation, redness, or peeling, you should reduce the frequency of use or the concentration. If your skin tolerates it well and shows no signs of irritation, you can continue using it regularly.

  • Proposed Formulation (L-Ascorbic 12%, LHA 5% (from 10% liquid), Lactic Acid 3%, Glutathione, Zinc PCA): This formula carries a high risk of causing severe irritation. This is because it combines multiple exfoliating and highly acidic ingredients at relatively high concentrations (LHA, Lactic Acid, L-Ascorbic Acid). Although LHA is generally milder than typical BHA and AHA, combining it with Lactic Acid (AHA) and L-Ascorbic Acid (which is acidic) can have a synergistic effect, leading to significant irritation. Adjusting the pH to not lower than 3.5 might help reduce irritation from L-Ascorbic Acid and Lactic Acid to some extent, but the risk from LHA still remains. It is not recommended to use multiple exfoliating ingredients simultaneously in a single formula. You should choose only 1-2 ingredients at appropriate concentrations and test on a small area of skin before applying to the entire face. If you wish to use multiple ingredients, they should be at very low concentrations or used on alternating days.

I hope this information is helpful. Please feel free to ask if you have any further questions.

Tags

Cosmetic Formulation Exfoliation Ingredient Interaction Serum Skin Irritation