Watery Brightening Essence Formulation

Based on your goal of creating a watery essence ("น้ำตบ") for skin brightening using the ingredients you listed, here is a suggested formulation focusing on achieving that texture and maximizing the effectiveness of water-soluble brightening agents.

To achieve a watery essence texture, it is best to exclude oil-based ingredients like Mineral Oil and emulsifiers such as Light Cream Maker or Butter Cream Maker, as these are typically used for creams or lotions.

While Phenylethyl Resorcinol (Sym-White) is an effective brightening ingredient, it requires an oil phase to dissolve and has specific pH requirements (optimal pH 4-5 for stability) that can be challenging to maintain when combined with Lactic Acid (which is most effective below pH 4.0) in a watery base. For a simple watery essence, it is recommended to focus on water-soluble brightening actives.

A suitable formulation for a watery brightening essence can utilize Alpha Arbutin and Lactic Acid, with a small amount of Xanthan Gum to provide a light, non-sticky body characteristic of an essence.

Recommended Formulation:

• Water: Balance to 100%
• Alpha Arbutin: 2%
• Lactic Acid (88%): Approximately 5.7% (Adjust as needed to achieve a final pH of 3.5-4.0)
• Xanthan Gum (clear gel type): 0.1 - 0.2%
• Preservative: As needed (refer to supplier's recommended usage rate)

Mixing Procedure:

1. In the water phase, disperse Xanthan Gum using a high-speed blender or homogenizer until it is fully hydrated and a light, clear gel forms.
2. Add Alpha Arbutin to the water phase and stir until completely dissolved. Ensure the water temperature is below 30°C when adding Alpha Arbutin.
3. Add Lactic Acid (88%) to the water phase and mix well.
4. Add your chosen preservative and any other water-soluble ingredients.
5. Mix thoroughly.
6. Check the final pH of the formulation using a pH meter. Adjust the pH to be between 3.5 and 4.0 for optimal effectiveness of Lactic Acid and stability of Alpha Arbutin. Use a small amount of alkali (like Triethanolamine) if the pH is too low, or a little more Lactic Acid if it is too high.
7. Continue mixing until all ingredients are uniformly dispersed.
8. Allow the formulation to set for a few hours if using Xanthan Gum, although the clear gel type sets relatively quickly.

This formulation provides the brightening benefits of Alpha Arbutin and Lactic Acid in a light, watery texture suitable for an essence. Remember to always perform a small test batch before making a large quantity.