Why cosmetic actives fail in cosmetic formulas

With such a vast amount of choice of active ingredients these days, almost all of which are backed by scientific efficacy data, it should be easy to formulate a high performing cosmeceutical product that delivers on its promises, right?

Wrong!

There are many reasons why cosmetic actives fail in cosmetic formulas, and it isn’t usually anything do with the active itself, but instead, how it is used in a cosmetic formulation and/or the formulation itself. Read on to find out common issues that cause cosmetic actives to fail in cosmetic formulas, and how to overcome these problems.

While some cosmetic active ingredients have very specific pH or charge environments in which they must be used, most cosmetic active ingredients are at the very least heat sensitive and must be held homogenously throughout the shelf life of the product in order to be effective.

When an active cosmetic ingredient is used in the presence of incompatible materials, charge or pH, it will degrade and/or lose its bioavailability and efficacy. Key active materials to be wary of include:

• Vitamin C: depending on the form, these materials can degrade very quickly in the wrong pH environment. Ascorbic acid (vitamin C) needs a pH of 3.5 - 4 to be stable; while more stable forms such as magnesium (or sodium) ascorbyl phosphate require a pH range of 6.0 - 7.0. Water continuous phases also cause rapid degradation of vitamin C. You may be able to source encapsulated or oil soluble forms which will improve the stability of this material to get the best results. This video compares different types of vitamin C and which are the most stable.
• Vitamin A: also very susceptible to pH changes, retinol and retinyl palmitate is best formulated at a range of 6.0 - 7.0. Consider using a vitamin A alternative, which are usually much more stable and without the irritation that can be caused by vitamin A.
• Dihydroxyacetone (DHA): this self-tanning agent is undoubtedly one of the most incompatible cosmetic ingredients you could formulate with. It works by reacting with amino acids of the stratum corneum to produce the desired tanned appearance, but this means it also readily reacts with any collagen, proteins or nitrogen containing compounds present in a cosmetic formulation. It is also incompatible with anionic emulsifiers, surfactants and most anionic gums/polymers, and must be added to a formula just below pH of 6.0, as it also causes a significant drop in pH over time. 
• Alpha and beta hydroxy acids: these materials all require a low pH (below 3.5, ideally 3.0) to be even 50% bioavailable. This causes several formulation issues when trying to thicken the product and ensure long term stability of the base formula itself, but is essential if you want the desired results.

How can you overcome issues of incompatibilities? Check supplier documentation carefully when reviewing the use of a cosmetic active - in particular, look for the required pH of the finished product for best results as well as any charge incompatibilities. If a tight pH range is required, consider using a pH buffer in the formulation to maintain stability - and performance - over a prolonged shelf-life.

Most cosmetic actives are not compatible with temperatures above 40˚C, so you can check for when it should be added to a cosmetic formula. For example, many suppliers may instruct you to add the material in the cool down phase, or they may specifically state a temperature under which it should be added.

Can’t find this information? Always check with your supplier. A cosmetic active ingredient needs the right formulation environment to give the best results. 

Cosmetic active ingredient efficacy data will always provide you with the results that can be expected from using a specific input, in a certain type of base formula, from specific application methods.

For example, it is common for a cosmetic active ingredient to be used at 5%w/w in an emulsion base that is applied twice daily, with results reported at 28 days.

If you are using a cosmetic active ingredient that provides efficacy data based on these criteria, then you would need to use that same cosmetic active ingredient at 5%w/w in an emulsion base that has instructions to apply it twice daily. If you were to use that cosmetic active ingredient in a once a week mask, for example, at 1%w/w, (or even if you used it at 10%w/w), you cannot expect to get the same results.

Look carefully at the supplier efficacy data to determine how the cosmetic active ingredient should be used in your finished product formula, paying careful attention to:

• the input that should be used based on the data input %w/w;
• the formulation base that was used for the efficacy data - if it was a serum base, then you should be adding it to a serum base; it if was an emulsion base, you should be adding it to an emulsion base; and
  
• how many times a day or week it was applied to get the reported results.

Any changes you make to the way it was used in the efficacy data will impact your results. It could still be effective, but you’d need to run in-vivo tests to find out for sure before making any claims. 

Some cosmetic actives, such as hydrolysed proteins and oil-soluble actives, need only reach the outer layer of the epidermis (or hair) to ensure the required results.

The majority of cosmetic active ingredients, however, need delivery to at least the mid-layers of the epidermis (stratum granulosum), which can be enhanced by including an osmolytic agent, such as glycerin or propanediol.

Cosmetic active ingredients such as peptides or stem cells will usually require delivery to the deepest layers of the epidermis, the stratum basale. If these tiny substances can’t traverse this distance, they won’t product the desired results; however, if you can get them there, they do deliver outstanding efficacy. This can often be achieved using the combination of an emulsion (amphiphilic) base with humectant agents and/or liposomal delivery agents.

Find out how to ensure delivery to your desired epidermal level with penetration enhancers in this video.  

Not all cosmetic active ingredients are created equal. There can be a myriad of ways to process active ingredients such as vitamins (particularly vitamin derivatives), extracts, peptides and stem cells.

What may appear to be the same material from one supplier does not necessarily mean it is; so ALWAYS use cosmetic active ingredients from the supplier who has provided you with the efficacy data.

When sourcing cosmetic ingredients that are widely reported in journals and therefore don’t necessarily have efficacy data (for example, acids and vitamins), always use a reputable supplier that has a trusted name in the industry to ensure you are getting what you pay for. Remember the analogy: pay peanuts, expect monkeys.

Paying for quality is the same as formulating with certainty, and that is what your consumer expects when they purchase the finished cosmetic product.

Remember to speak with your cosmetic ingredient suppliers at your nearest in-cosmetics event to ensure you are sourcing the best quality active ingredients as well as the required data to ensure the right input, in the right base, and avoiding any incompatibilities. 

Happy formulating! 

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