Article by: Perry Romanowski
As a cosmetic chemist, you will frequently be called on to evaluate a new raw material or to optimize its level. But unless you’ve done it before, you won’t have any easy method. Here’s one you can follow.
We’ll assume that you have a standard base formula with which you are starting. This is pretty standard practice in the industry.
The first thing you have to decide on is a starting level. To figure this out, you need to decide whether your driving force is performance or cost. On some level, it will be both but one of them should take prominence at first. Personally, I like to ignore cost in the beginning and focus on performance.
When focusing on performance the starting level should be the highest level suggested by the raw material supplier, or 1%, whichever is higher. The 1% level is nice to use because it is the maximum level you can use without affecting the ingredient list. The reason we say to use the supplier’s suggested level is because they will usually give the highest level they can. Suppliers are inclined to do this because they want to sell more product.
Make your batch
After you’ve figured out your starting level, make a batch with the new raw material. If you are working with a solution and a water soluble ingredient, you can post add the ingredient to a finished base. However, if it is a more complicated formula form or oil soluble, you should start from scratch.
Be sure to observe the effects the ingredient has on your formula (e.g. On appearance, viscosity, etc.)
Test with and without
After you’ve made your batch you should compare it to a sample of the base formula (without the ingredient). The comparison test really depends on what the raw material is supposed to do. So for a moisturizing ingredient, try the product out on your skin. A hair product you would test on your hair or a tress.
If you can’t tell any difference at this point, it’s probably not worth going any further with the ingredient. There are a lot of ingredients out there so you don’t want to waste time on ones that don’t show any differences at high levels.
Optimizing cosmetic raw material
Next, you have to optimize the level of your ingredient. This is an iterative process but you can be most efficient if you follow the “half and double” technique.
To use the half and double technique, you simply make one batch where you cut the level of the ingredient in half and another where you double the level. So, if your starting level was 1% you would make one batch using 0.5% and another using 2%. Then you evaluate the samples (blinded) and see if you can tell a difference. If you can’t tell a difference between the samples, you can repeat the test a few times just to make sure you’re not missing something. But if you still can’t tell a difference, then use the lower level. Repeat the process of cutting the ingredient level in half or doubling it until you get to a point where you figure out the exact, optimized level.
Using this process should get you to an optimized ingredient level within 7 batches.
In a future post, we’ll discuss in more detail how you can go about evaluating your prototypes in a “paired comparison” or triangulation test.