Article by: Perry Romanowski

In the previous post in this formula optimization series we covered the basic process of optimization and also the things you could optimize and how to measure them.  In this post we’ll cover some of the formulation techniques used to optimize formulas. 

Optimization formulation techniques

There are various ways you can use for optimizing your formula but here is a look at three of the most useful prototyping techniques.

  • Optimizing for cost
  • Knockout experiments
  • Ingredient level optimization

Cost optimization

Reducing the cost of your formulation is something that every cosmetic chemist will be asked to do. Even though you spent lots of hours getting just the right ingredient levels and the product meets your target benchmarks, you can have no doubt that a year from now your marketing department will ask you to make the product work the same but be less expensive.

We’ve previously covered some formula cost savings techniques, but the basic strategy is this.

  • Step 1 – Figure out the cost of each ingredient in your formula
  • Step 2 – Identify raw materials that contribute the highest cost
  • Step 3 – Make prototypes with lower level of those ingredients
  • Step 4 – Test the prototypes against the current formula
  • Step 5 – Modify the prototype until you match performance at lower cost

Figuring out the cost of the formula is not too difficult but it does require some math. We’ve previously done a video explaining how to determine the cost of a formula.

Once you figure out the cost you can make a few changes to your prototypes to optimize formula cost.

  • Reduce: First, you can reduce the level of expensive ingredients and also your claims ingredients.
  • Eliminate: You can eliminate any ingredients that have no effect.  And to figure out which one of those you can run a knockout experiment which we’ll be talking about shortly.
  • Replace: Replace expensive ingredients with less expensive ones.
  • Increase: Increase the amount of less expensive ingredients (e.g solvents like water)

Knockout experiments

While cost optimization will be something you do frequently, there are other things for which you need to optimize. That’s when doing a formulation knockout experiment comes in handy. A knockout experiment is just a series of formulas in which you replace one of the ingredients with the primary solvent. That way you knockout the ingredient and see what effect is has on the formula.

When you are performing the knockout experiment you should keep track of numerous formula changes.  To help identify ways to optimize manufacturing keep track of the speed of formulation. Also measure the specification numbers because you’ll be able to determine what ingredients can be adjusted if you have a problem in production.

Measure how the knockout formulas affect performance. This will give you an idea of what ingredients to increase to improve whatever characteristic you’re trying to change.  It will also let you know what ingredients aren’t necessary for the performance of the product.

Also conduct stability and safety tests to see how the ingredients affect those formula characteristics. When you’ve completed a knock-out experiment, you’ll have an incredible amount of knowledge about how your formula works and how you might optimize various characteristics in the future.

Ingredient optimization

While the knockout experiment can tell you a lot about your current formula, you’ll need to change the levels of your ingredients to make most optimizations. A knockout experiment is really just a way to reduce ingredient levels to zero percent.

Once you have a good idea of what ingredients are needed and what your formula looks like when they aren’t in there, you can try optimizing the ingredient levels. To start the first thing you need to know is what characteristic you want to optimize and what ingredient has an effect on it. If you’ve done your knockout experiment you know the effect that the ingredient has on the formula at it’s standard level and at it’s minimum level. So if you want to increase the characteristic, you increase the ingredient level, if you want to decrease the characteristic you reduce the level.

To adjust the level in the most efficient way you’ll want to either cut the ingredient % in half or double it. You also want to minimize changes. Don’t adjust more than one ingredient at a time or you won’t know which of the changes you made was responsible for the change in your formula.

The key to formula optimization

The most difficult part of formula optimization is finding the right tests to measure whether your optimized formula is significantly different than your starting formulation. Unfortunately, there aren’t a lot of great standard formulation tests you can do in the cosmetic industry. The exact test you run will depend on the type of product you are working with so it’s hard for us to cover specific tests here.  But I will give you some general advice when you are testing your products.

First, become an expert at evaluating your own product. There is no substitute for using products yourself. For hair products tress work can tell you some things but there is nothing that tells you as much as actually trying the products yourself.

Next, always do your testing on a blinded basis. Ideally, you’ll have someone else make your samples so you won’t know what is being tested. The less you know, the better your data will be. It’s easy for us to hope for some result then subconsciously make that result happen.

Finally, repeat your testing numerous times. One or two tests will not be good enough for you to make significant formula changes.  Single tests are fine for screening prototypes. But when you really want to know if a formula change is worth making, do multiple tests of a single variable.

Optimizing formulas will be something you spend a lot of time doing as a formulating chemist. Learn the techniques present above and you’ll turn into a complete cosmetic chemist.

Read part one of the cosmetic formula optimization series.

About the Author

Perry Romanowski

Perry has been formulating cosmetic products and inventing solutions to solve consumer problems since the early 1990’s. Additionally, he has written and edited numerous articles and books, taught continuing education classes for industry scientists, and developed successful websites. His latest book is Beginning Cosmetic Chemistry 3rd Edition published by Allured.

Leave a Reply

Your email address will not be published. Required fields are marked *