Cosmetic ingredient incompatibilities

Formulating with active ingredients with truly efficacious results can be a rewarding experience. It can however also be frustrating when cosmetic formulas don’t work the way they are promised.

If you are formulating with vitamins and acid ingredients in particular, there are several parameters within which you should be working.

There are important considerations when formulating with proteins and peptides also, to ensure efficacy and long-term stability. This article will summarise the most important cosmetic ingredient incompatibilities, along with tips on how to overcome some of these obstacles. 

Different vitamins will require different pH environments to ensure efficacy and bioavailability, and in fact, even the form of the vitamin can determine which pH environment it is best suited to.

Adding vitamins at lower temperatures is also important to ensure you get the best results, and in some cases, other ingredients may specifically need to be avoided.

Some vitamins may have their input limited by country specific regulations; make sure you check your local country requirements before formulating.

Below is a table that summarises common forms of vitamins, and their required pH and temperature environments - you can learn more about input requirements and benefits of using these and many more different vitamins in this blog.

Cosmetic acids can be difficult to formulate with, and stabilise in a cosmetic formula. Where they are added, you will need to be very careful about which polymer or viscosity modifier you choose to use - always look for electrolyte resistant (not tolerant) gums or polymers to help stabilise these formulas, and ensure all other ingredients can suit their commonly low pH requirements.

Cosmetic acid ingredients may also need special solvents to ensure they can be dispersed effectively into cosmetic formulas; however acids are usually heat tolerant.

Remember that when formulating with acids, there are often strict country-specific regulatory requirements. Make sure you check your local country regulations to comply!

Below is a table that summarises commonly used cosmetic acids and their required pH environments.

For more information on how to use various types of acids in cosmetic formulas, along with regulatory limits and input rates, watch this video.  

Proteins and peptides are made up of amino acids, which by their very chemistry, contain an amino group and peptide bonds. This makes them susceptible to degradation at low pH and high temperatures.

Strongly oxidizing ingredients such as benzoyl peroxide, ingredients that react with amino functional groups, such as dihydroxyacetone, and preservatives that require a low pH (<5.0) are not suitable to be used where collagen, proteins and peptides are also present.

Hydrolysed proteins, peptides and collagen should all be added during the cool down phase of a formula, or below 40˚C, to ensure efficacious and expected results. 

Be especially careful of potential active ingredient compatibilities when you are asked to formulate with multiple cosmetic actives.

For example, if asked to develop a formula containing vitamins A and C, you will need to select a form of vitamin C that can tolerate a pH of 6-7 to suit the vitamin A, and may find it best to use a vitamin A derivative to comply with local country regulations as well as reduce potential irritancy from the finished product.

Alternatively, you may be asked to formulate an acid product with proteins or peptides present. In this case, you will need to select an acid that is not pH dependent (generally an oil soluble form), or one that can be added to a cosmetic formula with a pH closer to neutral so as to ensure the best efficacy of the protein/peptide material.

There are many hundreds of cosmetic active ingredients now available for use with some outstanding performance results - however their use can be very pH and temperature specific, along with potentially other ingredient incompatibilities.

Make sure you check supplier documentation carefully to determine the most suitable final pH, temperature of addition, and ingredient combinations to ensure you are formulating the most efficacious finished formula.

Speak with your local suppliers or visit their booth at your nearest in-cosmetics exhibition to keep up to date with cosmetic active ingredient launches, innovative product concepts and incompatibility solutions, and individual raw material needs for the best formulation developments. 

Happy formulating! 

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