What are emulsifiers?
Emulsifiers are surface active agents (molecules) that have the ability to bind oil in water (O/W) or water in oil (W/O). The molecular structure of the emulsifier, the polar part, has an affinity with water and the non-polar part (fatty or oil chain) is attracted to the fatty phase of the molecule; forcing one of these liquids into separate drops, suspended and dispersed directly within the other liquid.
As these droplets are ‘guarded’ by the emulsifiers surrounding them, they are kept apart from each other ensuring the two substances do not separate but are kept in a stable mixture, enabling two usually non-mixable ingredients to mix together.
Now, is this considered a ‘bad’ thing? It depends entirely on the properties of the emulsifier as not all surface active agents disturbance the natural metabolism of the skin’s barrier defence systems.
First of all, let’s talk about the formation of the acid mantle that resides on the surface of the stratum corneum (outer layer of skin) as there is in fact an emulsifying action taking place on a cellular level that needs to be understood.
The epidermis contains keratinocytes (cells made of the protein keratin) which are protected by a delicate phospholipid bilayer known as the cell membrane. This particular cell membrane contains odland bodies (spherical membranes) which encapsulate important lipids such as ceramides, cholesterol, free fatty acids and phosphatidylcholine that are re-organized upon their timely release during the keratinocytes differentiation cycle to create the multi-lamellar lipid structure or bilayers; and this defence system will protect the skin against UV radiation, water loss and other external elements.
I want you to think of the skin like a brick wall. The ‘bricks’ of the integument are the corneocytes of the stratum corneum and the ‘mortar’ is the multi-lamellar lipid structure embedded between the corneocytes. The term ‘bilayers’ simply means two layers: oil and water.
Ceramides of the multi-lamellar lipid structure are the EMULSIFIERS of the sebaceous and sudoriferous secretions along with the skin’s Natural Moisturising Factor (water soluble molecules) that MAKE your acid mantle (oil and water film). If this metabolic emulsifying action that is the end result of the skin’s own metabolism did not take place, the first line of the skin’s barrier defence systems (acid mantle) would not be formed and the viability of the epidermis would be compromised; generating free radical damage, fast trans-epidermal water loss and the invasion of microorganisms.
As you can see from this detailed explanation, ceramides are perfect emulsifiers which is one of the reasons as to why Mary and I choose to work with dermaviduals because their product range contain these physiological components that not only support the skin’s barrier function, but also work in synergy with other molecular phospholipids such as phosphatidylcholine.
Phosphatidylcholine is a highly important and dynamic lipid that is obtained within all living cell membranes and is the number one precursor for replenishing the Stratum Corneum which in turn supports all of its physiological functions and focuses on the recovery of the skin’s barrier defence systems; especially when it comes to a disrupted skin. Phosphatidylcholine also allows for much better penetration of active ingredients for epidermal and dermal repair.
Let’s talk about lecithin which is derived from the soy bean and is the precursor for the ingredient phosphatidylcholine; a bioidentical lipid molecule with good emulsifying properties.
Phosphatidylcholine (PC) is an essential fatty acid containing omega 6 (linoleic acid) and choline which is an essential water soluble nutrient required for structural integrity and signalling for cell membrane communication. Emulsifiers can be substituted by membrane forming substances such as phosphatidylcholine and ceramides as these systems excel by their bioidentical composition and can be found in the form of cell membranes and the bilayers of the stratum corneum; therefore making these lipid components well tolerated by all skins.
The INCI terms for phosphatidylcholine is lecithin and PC is an essential component of all animals, herbal and human cell membranes and is extracted from soy lecithin (about 20% PC) by means of high pressure liquid chromatography; a process that ensures that phosphatidylcholine is free of soy proteins when undergoing the very expensive extraction procedure. Due to its physiological composition, lecithin is used in the food sector for the manufacturing of chocolates and mayonnaise, and as I just discussed, also in the cosmetic sector.
Phosphatidylcholine along with ceramides and other lipid components undergo a seven stage high pressure homogenization process that binds the formulation of the Derma Membrane Structure (DMS) creams together without manufacturing with conventional emulsifiers. DMS is skin identical and it’s specific composition of physiological lipids and membrane technology mimics the barrier layers of the skin chemically and physically. Other ingredients such as xanthan gum and jojoba oil obtained within dermaviduals are non toxic emulsifiers that do NOT cause the wash-out effect of both skin barrier and fatty skincare substances when the skin comes into contact with water.
dermaviduals formulates their product line without your typical conventional emulsifiers as these surfactants may build up within the multi-lamellar lipid structure and cause an undesirable wash-out effect of the phospholipid content every time the skin comes into contact with water or even its own secretions.
The simple law of physics details that oil sits on top of water; and when applied to skin this translates into epidermic lipids (bilayers) prevents evaporation of water from the epidermis and this results in better hydration of the lower cellular layers. Emulsifiers such as Sodium Laureth Sulfate (SLS) disturb the barrier of the skin and decrease surface tension; generating the water phase of the epidermis to become mixed with the oil phase of the skin (remember, oil sits on top of water) and causing the wash-out effect of important protecting substances.
Sodium Laureth Sulfate (SLS)
This surface active agent is perhaps one of the most harmful ingredients in personal care products. Sodium Laureth Sulfate is used in testing laboratories as the standard skin irritant to compare the healing properties of other ingredients. Industrial use of Sodium Laureth Sulfate include garage floor cleaners, engine degreasers and car wash soaps.
Research has shown that Sodium Laureth Sulfate may cause potentially carcinogenic nitrates and dioxins to form in the bottles of shampoos and cleansers by reacting with commonly used ingredients found in many products. Large amounts of nitrates may enter the bloodstream from just one shampooing which is absolutely horrific! Sodium Laureth Sulfate when used in skincare formulations dissolve skin lipids and promote xerosis (dry skin) and barrier disorderd skin conditions such as eczema, psoriasis, dermatitis, rosacea and acne.
A serious problem with ethoxylated surfactants is that those that utilise ethylene or propylene oxide in the chemical reaction are often contaminated with dioxane; a well known and potent carcinogen. A related toxic chemical (dioxin) and known carcinogen sprayed on the Vietnam jungle caused hundreds of thousands of birth defects and cancers in Vietnamese civilians and huge increases in the cancer rates of US and Australian army personnel. These surfactants listed on labels as ingredients ending with eth such as laureth or containing the phrase PEG (Poly EthyleneGlycol) or PPG (Poly Propylene Glycol).
Now, you might be thinking, but doesn’t dermaviduals contain Propylene Glycol? That is correct, however, let me explain the knitty gritty details. Propylene Glycol is used as an alternative to conventional preservatives and emulsifiers as it possesses beneficial anti-microbial and binding agent properties. This particular glycol is NOT listed as a preservative in the Amendment of the European Cosmetic Directive. Today, one thing is for sure that it’s neither a skin irritant nor shows notable allergenicity. 100% pure Propylene Glycol as used in dermaviduals preparations has neither toxic or hazardous properties. The alternative to using standard preservatives is the production of complete sterile manufacturing; and even though this is an expensive procedure, dermaviduals products are produced in this manner.
Another dangerous class of surfactants are amines. These are listed on labels containing the term TEA (Triethanolamine), DEA (Diethanolamine) and MEA (Monoethanolamine). All compounds containing TEA, DEA and MEA can undergo nitrosation with other chemicals to form nitrosamines, which are carcinogenic. One study found that 40% of products containing triethanolamine (TEA) were contaminated with these potential carcinogens. Some synthetic surfactants to be avoided:
Sodium or Ammonium Lauryl or Laureth Sulphate
Sodium Methyl Cocoyl Taurate
Sodiu, Lauroyl or Cocoyl Sarcosinate
TEA and DEA compounds
PEG (Polyethylene Glycol) compounds
Quaternium 7, 15, 31, 60 etc
Lauryl or Cocoyl Sarcosine
Disodium Oleamide or Dioctyl Sulfosuccinate
The reason for this article was because I came across a list of INCI ingredients online that sparked conversation, and I wanted to clear the air about a few ingredients that were mentioned.
An extremely common multitasking ingredient that gives the skin a nice, soft feel and gives volume to creams and lotions. Cetearyl Alcohol also helps to stabilize oil-water emulsions though it does not function as an emulsifier in itself and is typically used in skincare formulations of around 2-3%.
Cetearyl Alcohol is a so called fatty alcohol; a mix of cetyl and stearyl alcohol which are other two emollient fatty alcohols. Though chemically speaking, it is alcohol (as in, it has an -OH group in its molecule) and its properties are totally different from the properties of low molecular weight or drying alcohols such as alcohol denat.
Fatty alcohols have a long oil-soluble chain (non-polar part) that makes them absolutely non-drying and non-irritating which makes the ingredient totally okay for the skin.
Glyceryl Stearate is an emulsifier derived from palm kernel, vegetable or soy oil and is also found naturally in the human body such as the digestive system. It acts as a lubricant on the skin’s surface which gives the skin a soft and smooth appearance. Glyceryl Stearate easily penetrates the skin and slows the loss of water from the skin by forming a barrier on the skin’s surface. It has also been shown to protect the skin from free radical damage.
Emulsification and Digestion
Emulsification of fats is also a critical part of digestion. Most of the fluid in the digestive tract is water-based, so when you consume fats, they tend to form large globules and it is hard for the enzymes in your digestive system to break down dietary fats. As a result, your body uses an EMULSIFIER known as bile to break up these fat globules while also aiding in the absorption of fats and fat soluble vitamins.
To summarise this article, not all emulsifiers have detrimental properties as your standard surface active agents and not all will contribute to the wash-out effect of vital skin nurturing components. When it comes to choosing your skincare formulations, always do the research or speak to a skincare professional who understands cosmetic chemistry. As a practising corneotherapist, it is my duty to have a reasonable base knowledge of cosmetic chemistry and to understand what is not chemically beneficial to the integument, barrier defence systems and barrier disordered skin.
Corneotherapists MUST preserve the integrity of the epidermis at ALL times and to ensure that skincare formulations work with the physiological functions of the skin. Mary and I proudly distribute dermaviduals as they are the first corneotherapeutic range to be accepted by the IAC (International Association of Applied Corneotherapy) and focus on the repair and recovery of the Stratum Corneum and epidermal defence systems without undesirable side effects.
Written by Kai Atkinson (Practicing Corneotherapist)
Barrett-Hill, Florence. Cosmetic Chemistry: for the Skin Treatment Therapist