Hey Patreon, this month we are diving into some more formulating fun, covering Cetyl Alcohol (and Cetearyl Alcohol, but I’ll cover that in the next post). I wanted to take the time to talk about Cetyl Alcohol and its capabilities.
What is Cetyl Alcohol?
Despite the name, Cetyl Alcohol is not the drying, irritating alcohol you might be thinking of, like ethanol or isopropyl alcohol. Instead, it’s a fatty alcohol, derived from vegetable oils or coconut oil, that plays a versatile role in cosmetic formulations. It is a white, waxy solid that melts at a low temperature, making it an easy ingredient to work with in heated formulations.
Let’s dive a little deeper into the concept of HLB (Hydrophilic-Lipophilic Balance), which is crucial for understanding how to properly emulsify ingredients like Cetyl Alcohol into your formulations.
What is HLB?
The HLB system is a way of measuring the balance between the water-loving (hydrophilic) and oil-loving (lipophilic) portions of a molecule. It assigns a numerical value that helps cosmetic chemists determine which emulsifiers to use for different ingredients.
Essentially, the HLB system guides formulators in choosing the right emulsifier to mix oil-soluble and water-soluble ingredients together, creating a stable emulsion. The HLB scale ranges from 0 to 20:
Low HLB values (0-8) indicate that the ingredient is more oil-soluble (lipophilic). These emulsifiers are better suited for water-in-oil (W/O) emulsions.
High HLB values (8-20) mean that the ingredient is more water-soluble (hydrophilic) and is better suited for oil-in-water (O/W) emulsions.
Cetyl Alcohol, for instance, has an HLB value of around 15.5, meaning it’s more hydrophilic but requires an emulsifier with the correct HLB value to help mix it into a stable emulsion.
How the HLB System Works
When formulating, you often need to emulsify different oils, butters, or fatty alcohols (like Cetyl Alcohol) into your water phase. Knowing the HLB value of each oil-soluble ingredient helps you calculate the right amount of emulsifier needed to create a stable emulsion. The HLB value of the emulsifier you choose should complement the HLB values of your oil-phase ingredients.
For example, if you want to mix Cetyl Alcohol with water, you’ll need an emulsifier that has an HLB value compatible with Cetyl Alcohol’s HLB of 15.5. This ensures the ingredients blend properly and won’t separate over time.
Why HLB Matters
Stability: The right HLB value ensures that your emulsion remains stable over time, preventing the ingredients from separating into oil and water layers.
Texture: Properly balancing HLB values also influences the texture and feel of your product. A well-emulsified lotion or cream will feel smooth and luxurious, while an improperly emulsified product can feel grainy or separate quickly.
Compatibility: Different oils, butters, and waxes have different HLB values. By knowing these values, you can ensure the ingredients in your formulation are compatible and won’t destabilize the final product.
Practical Example of HLB in Formulation
Let’s say you’re formulating a lotion with the following ingredients in the oil phase:
Cetyl Alcohol (HLB 15.5)
Shea Butter (HLB 7)
Coconut Oil (HLB 8)
To create a stable emulsion, you’ll need to calculate the required HLB value of your oil phase. Once you’ve done that, you’ll choose an emulsifier (or combination of emulsifiers) that matches or is close to that required HLB value. This will allow you to emulsify the oil-soluble ingredients with water, ensuring your product remains smooth and stable.
Not an Emulsifier!
To clarify, Cetyl Alcohol is not an emulsifier! While it has an important role in formulations, it is classified as oil-soluble ingredient. Just like carrier oils or cosmetic butters, it requires an emulsifier to combine with water and prevent phase separation.
Why is it called an "Alcohol"?
Ever wonder why Cetyl Alcohol is called an “alcohol”? It’s not because it’s like the type of alcohol you find in hand sanitizers or spirits, but rather due to its chemical structure. Look closely at the molecular structure, and you’ll see a hydroxyl group (-OH) at the end of the carbon chain (refer to image at the top of the post). This hydroxyl group is why it’s classified as a fatty alcohol. Despite the “alcohol” in its name, it doesn’t dry out your skin or act as a solvent. Instead, it nourishes, conditions, and enhances the texture of your formulations.
Later in the week we will dive into Cetearyl Alcohol.
I will upload another formulation tomorrow!
Comments