Water-Based Serum Formulation Questions

Here are the answers to your questions regarding water-based serum formulation:

1. Mixing Water-Soluble Ingredients: Yes, water-soluble ingredients, including those containing Glycerin, can generally be mixed directly into the water phase of your formulation without needing a binder or cream maker. Binders and cream makers are typically used to thicken the product or emulsify oil and water phases, which isn't necessary for simply dissolving water-soluble components in water.

2. Penetration Enhancers in Water-Based Serum: Adding a penetration enhancer can be beneficial for improving the absorption of active ingredients into the skin. For a water-based serum, TransMoist™ (PPG-24-Glycereth-24) is a good option. It is water-soluble and helps ingredients penetrate the skin while also providing moisturization. It works well in combination with Glycerin. Another option is Tetrahydropiperine (Natural Penetration Enhancer), but it requires pre-dissolving in a suitable solvent like Propylene Glycol or Glycerin before adding to the formula, and care must be taken with temperature.

3. Water Percentage for Dropper Serum: For a water-based serum intended for use with a dropper, the viscosity needs to be low enough to be easily drawn into and dispensed from the dropper. This is achieved by minimizing the use of thickeners. While there's no strict minimum water percentage, the water phase (which includes water and other water-soluble liquids like glycols and Glycerin) typically constitutes a high percentage of the formula, often 80% or more, to ensure the desired low viscosity.