Understanding Your BHA Formula Questions

You've asked some important questions about your BHA formula, specifically regarding Polysorbate 20 and the role of pH. Let's break it down:

Can Polysorbate 20 be omitted?

Polysorbate 20 acts as a solubilizer and dispersant in your formula. Since Salicylic Acid powder is not water-soluble and needs to be dissolved in a solvent like Propylene Glycol, Polysorbate 20 helps to integrate this oil-soluble or solvent-soluble phase into the water phase of your serum.

Omitting Polysorbate 20 might lead to:

• Reduced Stability: The Salicylic Acid may not remain evenly dispersed throughout the serum, potentially separating over time.
• Lack of Clarity: Your serum might appear cloudy or hazy instead of clear.
• Texture Issues: The formula might feel less smooth or uniform.

While Salicylic Acid can be dissolved in Propylene Glycol, Polysorbate 20 helps ensure that this solution mixes well with the rest of the water-based ingredients, contributing to a stable and aesthetically pleasing serum. Based on the typical formulation methods for Salicylic Acid powder in water-based products, including a solubilizer like Polysorbate 20 is generally recommended for stability and clarity.

Is pH important for a BHA formula?

Yes, pH is very important for a BHA (Salicylic Acid) formula. Salicylic Acid is most effective as an exfoliant when the formula's pH is in a specific range, typically below 4.0. At this lower pH, a higher percentage of the Salicylic Acid is in its active, un-ionized form, which can penetrate the pores more effectively to help with exfoliation and clearing congestion.

However, a very low pH can also increase the potential for skin irritation. Formulators often aim for a balance between efficacy and tolerance. The Willow Bark Extract you are using also contains natural salicylates and works best in a pH range of 4.0-6.5.

Therefore, controlling and measuring the final pH of your formula is crucial to ensure the active ingredients are effective and the product is safe and well-tolerated by the skin.

How does mixing ingredients with different pH values affect the final pH?

When you mix ingredients with different pH values, the final pH of the mixture will be somewhere between the individual pH values of the components. It's not a simple average, as the concentration and buffering capacity (the ability to resist changes in pH) of each ingredient play a significant role.

For example, mixing an ingredient with a pH of 5 with an ingredient with a pH of 7 will result in a final pH between 5 and 7, as the staff previously mentioned. To achieve the desired final pH for your BHA formula (ideally below 4.0 for optimal Salicylic Acid efficacy, while considering overall formula stability and skin tolerance), you will need to measure the pH after mixing and adjust it if necessary using a pH adjuster.

In summary, while you might technically be able to omit Polysorbate 20, it's recommended for formula stability and aesthetics. pH is critically important for the efficacy and safety of your BHA serum, and the final pH will be a result of all ingredients, requiring measurement and potential adjustment.