I spent much of my career formulating hair care products including shampoos, conditioners, and styling products. One of the largest projects that I was ever involved in was qualifying a second source for our primary detergent, sodium lauryl sulfate. This required us to make multiple batches of each of the 13+ shampoo varieties we produced and run stability tests on them. We also had to do foam testing, salon testing, and packaging compatibility testing. It was a lot of work. And the interesting part was that we were simply substituting one supplier of Sodium Lauryl Sulfate with another supplier of Sodium Lauryl Sulfate. (We were qualifying Henkle I believe).
Anyway, as a young chemist I wondered why we had to do that. Why couldn’t we just substitute one supplier for another? The chemicals were both Sodium Lauryl Sulfate so there shouldn’t be a problem.
Well, this is something they don’t teach you in college chemistry. Industrial produced raw materials are rarely the same company to company and batch to batch. Here are the primary reasons why one company’s raw material is not the same as another’s even though it has the same INCI name.
Different starting materials
Most cosmetic raw materials can be made from a variety of starting materials. For example, sodium lauryl sulfate is made using lauric acid as a starting material. The lauric acid can come from coconut oil, palm kernal oil, or petroleum. Unfortunately, these sources do not result in a pure version of lauric acid but rather a distribution of fatty acids which contain mostly lauric acid. Coconut oil contains about 40% lauric acid and a significant amount of myristic, stearic & palmitic acids. It also contains about 8% of non-fatty acid material which can end up as a residual contaminate of the final product. All of these differences can result in a slightly different version of sodium lauryl sulfate even though it has the same INCI name.
Different production method
Another factor that makes one version of a cosmetic raw material different from another with the same name is the various production methods. As you may have learned in organic chemistry there are multiple ways to arrive at the same raw material. Sodium lauryl sulfate can be made by reacting lauryl alcohol with sulfur trioxide gas, oleum, or chlorosulfuric acid. It is then neutralized with either sodium hydroxide or sodium carbonate to produce the final ingredient. All of these different routes of synthesis will result in a material that is slightly different at the end. And other things like the manufacturing equipment, the quality control standards, and the final specifications can all impact the chemical properties of the final product.
Different residual ingredients
The other important factor is the residual ingredients that are either left over from the production process or added to preserve the product or improve the color. Sometimes raw material companies add bleaching agents to their products so they don’t look as yellow. These residual components can have a significant impact on your final formulation. In fact, very often there will be something in your final formula that reacts with one of the residual components in the new raw material.
Having raw material alternatives
While different sources result in slightly different raw materials, it is crucial that you have a second source for all of the raw materials that you use in formulation. Without a second source you are at the mercy of your supplier. If they happen to raise prices, you have no choice but to pay them. If they change the way they make the product it could impact the stability or functionality of your final product. And if they happen to go bankrupt, have an accident or otherwise stop producing the material you rely on, your business could be in trouble. Always have a secondary source qualified!