Marketing statements for hair conditioners contain a variety of terms to describe the properties of the products in a manner that is enticing to consumers. Included in these are familiar words such as: emollient, moisturize, seal, penetrate, repair, and condition. Ingredient savvy consumers often seek to attribute specific properties, such as “emollient” or “moisturizing” to groups of ingredients in an effort to predictably define which products can meet the unique needs of their hair type. Due to some ambiguity in the usage of many of these terms, a number of questions come to mind when endeavoring to categorize materials in this fashion.
What criteria must be met for a product to be considered a hair conditioner? What are the exact definitions of the various marketing terms when applied to hair care products? Are any of them interchangeable? What properties make an ingredient moisturizing, emollient, or conditioning? Is it possible for an ingredient to be both moisturizing and emollient? Are there more accurate and precise words that we could be using to describe these properties and ingredients? Obtaining the answers to these questions can alleviate much of the confusion surrounding additives in hair conditioning products.
What is a hair conditioner?
A hair conditioner is a product which, when applied topically, can improve the overall quality of your hair's surface and bulk properties. Their benefits include increased slip between hair strands (and easier detangling), a smoother cuticle surface, decreased porosity, optimized hydration, decreased electrostatic charge, added body and bounce, and increased strength, suppleness, and elasticity. Specialized products may also provide protection from thermal and UV damage, as well as improved color retention. Some of these effects are purely superficial and temporary, requiring frequent reapplication to maintain the properties, while others impart long term benefits by the reduction of damage on a daily basis.
In order to achieve this high level of performance, a conditioner formulation must combine a complicated array of ingredients that both individually and synergistically contribute different properties to the whole package. Generally, the most basic objectives a conditioner must meet are to provide hydration, lubrication, and occlusion to the hair. Two common and often confusing terms used to describe the properties of various ingredients in the product are “moisturizer” and “emollient”. These terms are used in variable ways in marketing statements and in the literature, and are a frequent source of confusion for users.
The essential qualification for an ingredient to be a moisturizer is that it must improve or maintain hydration levels of hair or skin. Proper levels of moisture (a delicate balance between too much and too little) help maintain the keratin structure and mechanical integrity of the hair. Hair with optimal water levels has more body, bounce, and better curl retention. Curly hair, with its greater porosity and complex protein structure is highly susceptible to water loss, and is thus in particular need of restoration of moisture on a regular basis.
True moisturizing agents are humectants, which are extremely hydrophilic molecules that use hydrogen bonding to attract and hold water molecules from the local environment, making it available to the hair. Some examples of these types of ingredients are glycerin, propylene glycol, panthenol, honey, agave, and aloe vera. Additionally, a good moisturizing formula will include an occlusive agent, a hydrophobic ingredient which seals moisture into the hair by forming a barrier film on the surface of the hair. There are some natural oils that have sufficient amounts of hydrophilic bits on their structures that they can act as both occlusive barriers and mild humectants, and some larger molecule sugars that have enough hydrophobic substance to also perform both roles.
The term emollient is probably most appropriate for use in skin care applications, but it has been incorporated into the hair care vocabulary, which is often a source of confusion. An emollient skin care ingredient is one that has good spreadability onto the skin, where it forms an evenly distributed film that softens and smoothes the surface without feeling greasy or tacky. So, if we extrapolate those properties to hair care, we can assert that an emollient for hair should easily form a smooth, even film on the surface of the hair, should soften the hair, and should not yield an unpleasant sticky or greasy texture.
More specifically, emollients for hair are usually hydrophobic oils that form films on the surface of the hair, where they often act as anti-humectants or sealers. They are lubricants and provide increased slip (decreased drag) between adjacent hair strands, which makes detangling much easier. They also reduce tangling in general by smoothing and flattening the cuticle surface, which can also add shine and gloss to the hair. The best ones impart a soft, silky feel to tresses, while lesser ones may weigh it down or make it feel greasy. Some can penetrate the interior structures of the hair and act as plasticizers, improving elasticity, toughness, and suppleness.
Common emollient ingredients include silicones (dimethicone, amodimethicone, cyclomethicone, etc.), fatty alcohols, fruit and vegetable-derived oils and butters, proteins and hydrolyzed proteins, mineral oil, petrolatum, and polyquaterniums (cationic polymers). Many of these are entirely hydrophobic, but hydrolyzed proteins and fruit and vegetable oils are typically smaller molecules with fatty acid components that are hydrophilic. This can enable these to act as both emollients and as mild humectants. Some of these can also penetrate through the cuticle layer into the cortex and significantly improve the mechanical properties of the hair (although for some people, this can weigh the hair down and disrupt curly pattern or swell the hair strand and raise the cuticle, creating frizz). In extreme humidity, films comprised of these oils can become sticky and dull-looking due to inclusion of water molecules.
Most anti-frizz and anti-humectant serums are comprised of extremely hydrophobic, synthetic emollients such as silicones, emollient esters, and mineral oil or petrolatum. These typically sit directly on the surface of the hair and act as occlusive agents, barriers which prevent moisture from escaping from the cortex or getting into it from a humid environment. People who do not use shampoo or use only mild shampoos should be extremely cautious about these types of ingredients and products.
What You Need to Know
Good hair conditioners and hair treatments provide a variety of benefits, including optimizing the hydration and oil levels of your hair and protecting the surface. Because the terms moisturizer and emollient are actually referring to fairly complex processes and multiple properties, it is not surprising that they are often used incorrectly or interchangeably, which can be confusing. Marketing materials need to capture your attention quickly, but are not always entirely accurate in their oversimplified jargon. For this reason, it is considerably more helpful for you as the consumer to determine what your individual hair needs are and to look for ingredients or combinations of ingredients that can meet those needs and to use specific, well-defined terminology to describe those ingredients.
Do you need a humectant to add moisture to your hair? Do you need a slip agent to reduce tangling (oils, silicones, polyquats, simple quats)? Do you need a fruit or vegetable oil to decrease porosity and to add softness and elasticity to your hair? Do you need a water-repellent sealer to prevent frizz in your ultra-humid environment (silicones, mineral oil, serums, anti-humectants)? Do you need a good conditioning agent to soften, detangle, or to give thermal and UV protection and increased color retention (amodimethicone, polyquats)? Knowing exactly what you want and need for your hair and understanding the terminology and properties of the various categories of ingredients can demystify and simplify the whole process.