Formulation

The Water Phase, or Aqueous Phase, is going to include the formula’s hydrophilic (water-loving) substances that dissolve or mix into water or other water-phase solvents. In most cases, the water phase is going to be the first phase of formulation, creating the base for a cosmetic formula.

 Examples of water phase ingredients include:

• Solvents: Water and Butylene Glycol will be the solvents discussed in this website. Solvents such as these are the true base of the formula and will help all the other water-soluble ingredients be dissolved and dispersed throughout the mixture.
  
  

• Humectants: Moisture-providing ingredients that are water-soluble, such as Glycerin and Hyaluronic Acid.
  
  

• Water-Soluble Ingredients and Actives such as Caffeine or Chelating Agents like Disodium EDTA.
  
  

• Thickeners such as carbomers and xanthan gum are also common in the water phase. These are added to increase viscosity and reach desired textures, such as when formulating creams, lotions, serums, and anything else needing a more viscous consistency.

Many people choose to add pH Adjusters and Stabilizers into the water phase to simplify the end formulation processes.

Water phases are often heated as high as 75°C in order to help stubborn solids dissolve and effectively combine with oil phases in emulsification.

• This is where all lipophilic (oil-soluble) ingredients are dissolved. Many oil phases are gently heated, functioning to facilitate emulsification with the water phase. However, some oil-soluble ingredients are heat-sensitive, so it’s important to keep the temperature below 40°C in specific cases, such as when working with tocopherols (Vitamin E).
  
  Oil phases may include:
  
  

• Carrier oils: These solubilize lipophilic, oil-soluble ingredients. They also help support the skin’s barrier by providing cells with lipids and have emollient characteristics such as softening and conditioning effects on the skin. Examples include safflower oil, sunflower oil, grapeseed oil, and many others.
  
  

• Antioxidants: Tocopherol (Vitamin E) is commonly used, and in our case, we’re working with alpha-tocopherol—a more sensitive form of Vitamin E that may be supplied in an anhydrous form. This should be dissolved in the oil phase below 40°C to preserve its integrity.
  
  

• Emulsifiers: These are substances that enable the oil and water phases to combine into a stable, homogeneous mixture. Emulsifiers are amphiphilic substances, meaning they have a hydrophilic (water-loving) head and a lipophilic (oil-loving) tail. The emulsifier used throughout this project is PEG-40 Hydrogenated Castor Oil.

After the oil and water phases have been combined and cooled below 40°C, heat-sensitive ingredients can be added to the mixture.

Examples include:

• Preservatives: It is important to pH test the formula before adding preservatives to ensure their effectiveness. For example, Optiphen Plus is effective at preserving formulas with a pH of 6.0 or lower. If the pH exceeds 6, the salicylic acid component in Optiphen Plus may degrade, compromising the preservative system and leaving the formula vulnerable to microbial growth and other issues that would otherwise be prevented.
  
  

• Actives: Ingredients such as botanical extracts should be added during the cool-down phase due to their sensitivity to heat. This phase may also include vitamins like D-Panthenol (Vitamin B5) and peptides, which can lose the ability to provide skin benefits or degrade at higher temperatures.
  
  

• Fragrances and other heat-sensitive ingredients: These are best added once the mixture has cooled to preserve their aromatic and functional integrity.
  
  

• pH Balancing Agents: Ingredients such as citric acid, sodium hydroxide, and L-arginine are typically added during the cool-down phase. This timing allows for final pH adjustments both before and after the addition of preservatives, ensuring the greatest stability and preservative effectiveness.