How to Thicken a Watery Serum

To make a serum less watery and increase its viscosity, you can use thickening agents or rheology modifiers. Several ingredients are commonly used in serum formulations:

• ThixoGel™ (Thixotropic Gel Maker): This is a gel-forming agent for water-based formulas. It creates a thick yet liquid gel texture that flows easily when force is applied (like squeezing from a bottle) but remains stable when still. It's suitable for formulas needing to suspend ingredients like powdered sunscreens or beads. It requires heat (below 80°C) to dissolve. The recommended usage rate is 1.0% for general gels.
• CreamThick™ (Hydroxypropyl Starch Phosphate): An easy-to-use water thickener that doesn't require heat. It's highly resistant to electrolytes and works well in a wide pH range (3-9). It provides a milky white gel texture and leaves a soft, smooth, non-sticky feel on the skin. Use at 0.5-5% (recommended 4% if used alone, or 0.5-3% when combined with other thickeners).
• Sepimax Zen: A thickener and formula stabilizer with very high tolerance to salt and pH variations. It creates a gel texture in the water phase and is easy to use by sprinkling the powder into the liquid and mixing. Use at 0.5-2%.
• CreamMaker EG™: Acts as both an emulsifier and a thickener, suitable for creams, lotions, and serums. It improves texture, creating supple gels, and is easy to use in cold process formulations. It can be added to either the water or oil phase and is stable across a wide pH range (5.5-12). Use at 1-3% (1.5% recommended for general formulas).

The choice of thickener depends on the type of serum (water-based or emulsion), other ingredients in the formula, the desired pH, and the final texture you aim for.