When it comes to conditioning ingredients used in personal care products, there are three major ones:
|Humectants||Dial up the moisture content in the top layers of the skin by attracting and retaining water|
|Our skin and hair are semi- permeable (allowing stuff to pass through). If water can get in, it can get out as well which is why it is advised to use occlusive ingredients after application of humectants|
|Occlusive ingredients||Do not add moisture to the skin but prevent you losing it by forming protective layer on the skin|
|Occlusive agents are often combined with ingredients that help to improve the feel of the skin and hair|
|Emollients||Fill in the cracks and smooth out rough edges in the skin making the skin feel soft|
Humectants are the ingredients that dial up the moisture content in the skin or hair by attracting water molecules. When it comes to personal care product formulation specifically, humectants perform following functions:
1) Humectants help the solubility of a chemical compound’s active ingredients thus promoting the active ingredients’ ability to penetrate the skin
2) Humectants help to hydrate without causing damage to the protective barrier function
3) Humectants counteract dehydrating ingredients and solutions (soaps, some alcohols, etc)
Various humectants have different ways of behaving because they differ in water binding capacity at different levels of humidity. As such, we will explore the types of humectants used in personal care and the dynamic of their interaction with humidity.
Types of humectants
Our bodies produce hyaluronic acid and urea which are humectants in nature. As for the humectants that are topically applied by means of personal care products, they are:
|What do they do?||Attract moisture to the surface of the skin / hair
Deliver major moisture and nutrients to the deepest layers of the skin
|Lock the moisture to some extent but do not provide any noteworthy nutrients or benefits
|Examples||– Aloe Vera
– Seaweed, algae and other marine extracts
– Hyaluronic acid
– AHA (Alpha hydroxy acid)
– Butylene glycol
– Tremella extract
– Sodium PCA
– Sodium lactate
|Be aware||Natural humectants form a film with thicker molecules over the skin and hair which makes it harder for the water to escape||Synthetic humectants are commonly used in personal cure because they are less expensive to produce. However,synthetic humectants are made up of small molecules which helps water to escape easily.
Moisturizers that use synthetic humectants are usually the ones that moisturize the skin in the short-term and dry out the skin in the long – term perspective
Humectants are the ingredients that have the potential of delivering great results if you understand their nature and use them accordingly. As mentioned above, major benefit of humectants is that they attract water. However, humectants do not distinguish between water taken from the outside environment and water taken from our body which means that the party more rich in moisture will serve as a source of water. In other words,
– if it is humid outside, humectants will bring water from the outside environment into your skin and hair making it more supple and moisturized
– if it is dry outside, humectants will actually pull too much moisture from the deeper layers of the skin and hair to bring it to the surface thus contributing to dehydration.
To counteract the loss of moisture, it is always suggested to use occlusive ingredients after application of humectants in order to seal the water and create/ enhance protective barrier. However, let’s have a closer look at humidity so we can understand the above mentioned dynamics better and discover the guiding principles of humectant use in personal care.
Humectants and Dew Point
Humectants are most beneficial when the moisture content of the air is high. That said, there is substantial confusion in understanding of the concepts of “relative humidity” and “dew point” which actually is the tipping point when it comes to you realizing benefits or adverse effects of humectants use.
|Relative Humidity (HR)||Dew Point|
|The amount of moisture in the air compared to what the air can “hold” at that temperature!!!! As such it is measured as a percentage (%)
Relative humidity depends on the temperature as warmer air can hold more water vapor as opposed to cool / cold air
|Temperature that the air needs to reach in order to form dew or moisture in the atmosphere! As such, it is measured in degrees (F or C)
|Not informative for the purpose at hand||30 F (-1 C) and below – very dry / dry
30 – 40 F (-1 – 4 C): mild
40 – 60 F (5 – 16 C): somewhat humid
60 F ( 17 C) and above: humid
Since humectants are commonly used in skin and hair care products, you can plan your personal care routine by checking the 10 – day weather forecast for your locality at Wunderground where Dew Point is clearly specified.
Developing your personal care routine, do remember that ACs remove moisture from the air making it drier thus adjust use of humectants and occlusive agents.
Occlusive skin conditioning agents perform in such a manner that the evaporation of the water from the surface of the skin or hair is blocked. Occlusive agents are lipids which, due to their insolubility in water, provide best barrier to water vapor transport. Occlusive agents tend to stay on the surface of the skin / hair overtime providing long – lasting occlusive film. They are most effective when applied to wet skin or hair.
Relationship between humectants and occlusive agents is essential to development of balanced skin – and hair – care routines. If you remember I have previously mentioned that balanced personal care requires that:
– You identify which active ingredients you need and their solubility (whether they dissolve in water or oil)
– You incorporate hydration as well as lipid barrier protection in your routine
Thanks for reading,