Formulation Advice Based on Staff Feedback

Thank you for providing your formulas and questions. Based on the previous discussion with the staff and the properties of the ingredients, here is a review of your formulas and recommendations:

General Feedback

• Manual Mixing: As the staff mentioned, formulas using emulsifiers like SiliSolve Plus or Light Cream Maker require mechanical mixing (such as a high-speed blender or homogenizer) to properly combine the oil and water phases and create a stable cream or lotion. Manual stirring is generally not sufficient.
• pH Adjustment: You can use Citric Acid to lower pH and Sodium Hydroxide (or KOH) to raise pH. While pH paper gives an estimate, a digital pH meter is highly recommended for accuracy, especially with pH-sensitive active ingredients like AHA, BHA, and Vitamin C, where precise pH control is crucial for efficacy and stability.

Formula 1: Face Cream (Modified)

• Removing L-ascorbic acid from this formula is feasible.
• You can use Light Cream Maker as your emulsifier. However, as the staff noted, the presence of Deoxyarbutin might make it challenging for Light Cream Maker to achieve sufficient thickness and stability. If you encounter this issue, adding around 0.5% of AnyGel (Dehydroxanthan Gum) can help improve the viscosity and stability of the cream.

Vitamin C Essence/Serum Base

For a Vitamin C essence or serum, especially if using L-ascorbic acid which requires a low pH (ideally below 3.5) for stability and effectiveness, consider these bases:

• AnyGel (Dehydroxanthan Gum): This is an acid-tolerant gelling agent suitable for creating a gel base that can maintain a low pH. You would create the gel base first and then incorporate your L-ascorbic acid.
• CreamMaker Acid™: This emulsifier is specifically designed for formulations with low pH. It can be used to create a cream or lotion texture that is stable with acidic ingredients.
• Hyaluronic Acid Gel Base: This base provides hydration but typically has a pH (5-6) that is too high for L-ascorbic acid stability. It would be more suitable for stable Vitamin C derivatives or if you formulate L-ascorbic acid in a separate, compatible low-pH system before adding.
• Ascorbyl Glucoside 20% Gel (MaxActivate™): This is a ready-made gel base containing a stable form of Vitamin C (Ascorbyl Glucoside). It's easy to use but contains a specific active ingredient, so it may not be suitable if you intend to use L-ascorbic acid or other Vitamin C forms.

Formula 2: 10% AHA Gel

• The staff was correct that Pro Polymer is not suitable for a formula with 10% Glycolic Acid due to the resulting very low pH (likely below 2.5), which exceeds Pro Polymer's tolerance.
• Using AnyGel (Dehydroxanthan Gum) or Xanthan Gum as recommended by the staff is appropriate, as they are more acid-tolerant.
• Your proposed method of creating the gel base with AnyGel first and then adding the dissolved Glycolic Acid is a suitable approach.
• Adjusting the pH of the Glycolic Acid solution before adding it to the thickener is not recommended, as raising the pH significantly reduces the efficacy of Glycolic Acid for exfoliation.

Formula 3: 2% BHA

• The staff was correct that dissolving Salicylic Acid powder in Isopentyldiol and then mixing with water will cause precipitation. Using Complex Salicylic Acid (Powder, Water-Soluble) is the correct solution.
• Your proposed 100g formula using 5g of Complex Salicylic Acid is correct in terms of achieving 2% active BHA (since Complex Salicylic Acid is 40% active). However, the water amount needs adjustment. For a 100g total batch with 0.2g EDTA, 5g Complex Salicylic Acid, and 1g Mild Preserved Eco, the water amount should be 100 - 0.2 - 5 - 1 = 93.8g.

Formula 4: 10% AHA + 2% BHA Body Lotion

• As the staff explained, Light Cream Maker is not suitable for this formula due to the low pH required for AHA/BHA efficacy (below 3.5, and likely below 2.5 with 10% Glycolic Acid), which is outside Light Cream Maker's stable range.
• Using NaOH to adjust pH with Light Cream Maker is also problematic due to electrolyte incompatibility.
• For an acid-stable lotion or cream base suitable for AHA/BHA, consider using CreamMaker Acid™. This emulsifier is specifically designed to be stable and effective in low pH formulations.
• Alternatively, you could use SureCream™, which has a wider pH tolerance (3.0-10.0) and better electrolyte resistance than Light Cream Maker. As the staff suggested, combining SureCream™ with a small amount of AnyGel might be beneficial for enhanced stability and viscosity in a challenging formula like this.

I hope this detailed feedback helps you refine your formulations!