Lotion Formulation Advice

Based on your lotion formula and the issues you encountered (hard to spread, white streaks), here is some advice:

1. Texture Issues (Hard to Spread, White Streaks)

The white streaks and difficulty spreading are likely due to the emulsification system you used (Stearic Acid + E-wax) not being fully compatible with your oil phase or the emulsification process (heating and mixing) not being complete or optimal. This system requires precise heating and mixing to form a stable emulsion without separation or crystallization of waxes/fatty acids, which can cause the white, streaky appearance.

2. Using Mineral Oil

Mineral oil can indeed help improve the spreadability of a cream or lotion because it is a lightweight, non-polar oil. However, the primary issue you're facing seems related to the emulsifier system and emulsion stability, not just the oil type. While mineral oil can make the texture feel smoother, it might not solve the white streak problem if the emulsification itself is unstable. Concerns about mineral oil are often related to its source (petroleum-based) and potential for feeling occlusive, but it is widely used and considered safe in cosmetics when properly refined.

3. Improving Spreadability and Moisturizing Properties

To get a lotion that spreads easily and is very moisturizing, consider the following:

• Change the Emulsifier: As suggested, switching to a different emulsifier system designed for easier use and better texture might be the most effective solution. Emulsifiers like Sepiplus 400 or Satin Moose are often recommended for DIY formulations as they are cold-process (don't require heating the oil and water phases separately to high temperatures) and can create stable, pleasant-feeling emulsions quickly. These types of emulsifiers can significantly improve spreadability and texture compared to traditional wax/fatty acid based systems.
• Add Humectants: Ingredients that attract and hold water, like Glycerin (which you already included) and Propylene Glycol, are excellent for boosting moisturization and can also improve the slip and spreadability of the product. Propylene Glycol can be used at a rate of 1-20% in lotions and creams.

4. Changing Emulsifier

Yes, changing the emulsifier is a strong recommendation to address the texture issues. The Stearic Acid and E-wax system can be tricky to work with for beginners and may not be the best fit for achieving a light, easily spreadable texture without white residue, especially if the heating and mixing conditions aren't perfect. Emulsifiers like Sepiplus 400 or Satin Moose are much simpler to use and often yield superior textures for DIYers.

5. Adding Vitamin C

Yes, you can add Vitamin C to your lotion. Vitamin C Ester (Ascorbyl Palmitate) is an oil-soluble form of Vitamin C that is more stable than L-Ascorbic Acid, especially in oil-based or emulsion systems. It acts as an antioxidant, can help stimulate collagen production, and may contribute to skin radiance. It is typically added to the oil phase during formulation. The usage rate for Vitamin C Ester (Ascorbyl Palmitate) is usually between 1-8%.

Adding Propylene Glycol, as you also asked, will indeed help with both spreadability (acting as a lubricant and viscosity reducer) and moisturization (as a humectant). It can be added to the water phase or the final product at a recommended rate of 1-20%.