Creating a Formula Similar to Paula's Choice BHA 9

To create a formula similar to Paula's Choice BHA 9, which features a high concentration of time-released salicylic acid (BHA) along with soothing and conditioning ingredients, you can focus on selecting key components that provide similar functions.

Key Ingredients and Alternatives

1. Timed-Release Salicylic Acid: The core active ingredient. Paula's Choice uses a 9% concentration of time-released salicylic acid. For DIY formulations, especially for leave-on products, using an encapsulated or complexed form of salicylic acid is recommended for gentler, timed release compared to standard salicylic acid. Options include:

   • Encapsulated Salicylic Acid (available in liquid or powder forms suitable for leave-on, such as ActiveRelease™ Salicylic Acid or Complex Salicylic Acid powder types). Note that the liquid encapsulated type found in search (Encapsulated Salicylic Acid (Liquid, Timed-Release, Wash-Off)) is specifically for rinse-off products, but a leave-on liquid type also exists.
   • The maximum allowed concentration for Salicylic Acid in over-the-counter cosmetics is typically 2% (which corresponds to 6.6% of the Encapsulated Salicylic Acid 30% liquid type).

2. Soothing and Anti-Irritant Ingredients: To counteract potential irritation from BHA, incorporating ingredients with calming properties is crucial. Based on the original formula and suggestions, consider:

   • Avena Sativa (Oat) Kernel Extract: A known anti-irritant (e.g., Avena sativa (Oat) Extract (Water Soluble)).
   • Beta Glucan: Excellent for strengthening skin and reducing irritation (e.g., Beta Glucan (Saccharomyces cerevisiae extract), Beta Glucan 70% (Oat Extract, Water-Soluble), Beta Glucan 90% (Oat Extract, Water-Soluble)).
   • Vitamin B5 (Panthenol): Helps nourish skin, reduce inflammation, and support wound healing (e.g., Panthenol (Vitamin B5, DL-Panthenol, Powder), D-Panthenol Care (Pro-Vitamin B5, 100% Liquid)).
   • Bisabolol: Derived from chamomile, known for its anti-irritant properties (e.g., Natural Bisabolol (Brazil Chamomile), Bisabolol (Alpha Bisabolol, Bisabolol RAC)).

3. Conditioning and Moisturizing Agents: Ingredients to improve skin feel and hydration.

   • Glycerin: A common humectant.
   • Arginine: An amino acid and skin-conditioning agent. Can be sourced individually or as part of a blend like Natural Moisturizing Amino Acids.
   • Hydrolyzed Proteins: Such as Hydrolyzed Pea Protein, can act as conditioning agents.
   • Natural Moisturizing Amino Acids: A blend mimicking the skin's natural moisturizing factors, providing hydration and supporting skin repair.

4. Solvents, Thickeners, Stabilizers: Ingredients like Propylene Glycol, PEGs, Water, Butylene Glycol, Polysorbate 20, and Disodium EDTA are standard formulation components used to create the desired texture, stability, and help dissolve other ingredients.

pH Adjustment

Yes, pH adjustment is important when formulating with salicylic acid. While standard salicylic acid requires a low pH (typically 3-4) for optimal exfoliation, which can be irritating, encapsulated or timed-release forms are designed to be gentler and may be effective at a slightly higher pH (the description for Encapsulated Salicylic Acid (Liquid, Timed-Release, Wash-Off) mentions a pH around 5.0 during action). However, the final pH of your formulation should still be within a range that ensures the stability and effectiveness of all ingredients, particularly the salicylic acid, and is suitable for skin application. You will likely need to adjust the pH of your final mixture using an acid (like citric acid or lactic acid solution) or a base (like sodium hydroxide solution) to achieve the desired range, typically between pH 4-5 for BHA products.

Formulation Approach

A simple approach, as suggested in the forum reply, is to first disperse or dissolve the encapsulated/complexed salicylic acid in water. Then, incorporate the soothing, conditioning, and moisturizing ingredients. Finally, add necessary solvents, thickeners, stabilizers, and adjust the pH. Always follow the specific mixing instructions and usage rates for each raw material.

Remember to perform stability testing on your final formulation.