Stop, that doesn’t sound natural. What are Polyglyceryl esters?
While working on the New Directions help desk I get asked lots of interesting questions about the backstage world of cosmetic manufacture. This is just one example of what people out there want to know. Enjoy!
Every emulsion needs at least one emulsifier and when your customers demand natural you have your work cut out! Further, while more and more manufacturers are going down the plant based, non-ethoxylated route not everyone is and with INCI names being complex and technical sounding, it is tempting to just run and hide rather than try out the new stuff. So, before you get the spade ready it’s time to sit back, relax and listen to a little story about polyglyceryl esters – a group of chemicals that may just save your natural formulating life!
Q) OK, first explain the name for me please?
A) Poly = many and glyceryl = glycerine. Basically this is a polymer (or lots of) glycerine molecules that have been joined together in a way that results in a bigger and more moisturising molecule. It is possible to control not only how long the chain ends up but also where each glycerine joins on (like holding hands). This gives rise to many interesting properties as you will find out if you start using these ingredients.
The ester part comes in when you add a fatty acid (e.g.: lauric/ stearic/ oleic) to the polyglyceryl under alkaline conditions. This breaks enough of the internal bonds to enable the two chemicals to join up forming a new molecule which is now called an ester due to the type of bond created.
They don’t sound so ‘chemical’ now do they?
Q) So what properties do these new ingredients have and why?
A) Well, as you know glycerine is water-loving due to its structure and fatty acids contain long tails which are oil loving. Put both of these onto the one molecule and you get something that can marry up both phases of your formulation – otherwise known as an emulsifier! Modifying the fatty acid chain length and/or the polyglyceryl weight changes the emulsification power. On top of that the vast quantity of glycerol functional groups makes these emulsifiers very moisturising and mild to the skin.
Q) Are polyglyceryl esters always plant-based?
A) Not always as it is possible (but no longer usual) to source both glycerine and fatty acid from animal fats. It is also possible to get both from petroleum and for that reason it is worth asking about the origin of the ingredient before using it – especially if you are making ‘animal/ petroleum free’ claims.
Q) Sounds great, so what is so good about Decaglyceryl Monolaurate!
A) Decaglyceryl Monolaurate is a non-ionic surfactant with a HLB of 14.8 making it highly water-soluble and therefore good to use as a mild cleaning and degreasing additive. It would also be good to pair up with a lower HLB ingredient (something upwards of HLB 8) as part of an emulsifier for oil in water cream or lotion. Finally it could be used to help solubilise small amounts of oil – say essential oils or fragrances into your water phase (forming a micro-emulsion).
Q) You mentioned about pairing it up with another surfactant – what other one would you recommend?
A) Well, that would depend quite a bit on your formulation but to give you an example if you were making a mild baby lotion that contained a little oil in water you may want to mix the Decaglyceryl monolaurate with some Sodium Stearoyl Lactylate to ensure that you get a more robust emulsion. As both of these surfactants have a high HLB they will also help to solubilise any fragrance that you have added – including many essential oils.
Q) What else are polyglyceryl esters used for?
A) They are widely used in the food industry for emulsifying bakery products, keeping chewing gum moist and to replace some fats and are used in the cosmetics and pharmaceutical industry to help hold creams together, modify viscosity of emulsions and disperse and solubilise fragrances and other active ingredients. Overall they are highly regarded due to their mildness, flexibility, moisture holding capacity and biodegradability. They can also be produced sustainably from renewable resources meaning that it won’t just be your skin care product that feels good.
Polyglyceryl esters such as those mentioned above can be found in many of your ‘green’ skin care products.
Look out for the following INCI names on the label:
Polyglyceryl-3 Stearate / Laurate (you can also replace the 3 for another number)
If you are looking to use these in your own skin care formulations you can get more information from your local chemical supplier. For those small businesses we recommend New Directions.