In this article about hair care products, you will learn about the hair structure, the different product types in the haircare industry, the common ingredients used and what they do, the formulation of shampoos, conditioners and dry shampoo as well as the regulation and claims of these products.
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Hair Physiology
Hair papilla
The only part of the hair where blood vessels reach. This is where mitosis occurs (the generation of new cells). As more and more cells are formed, it pushes the existing cells outward resulting in long strands. The papilla provides oxygen and nutrients required for cell division.
Sebaceous glands
These appendages are found on the side of the hair follicle but can also be found separately in the dermis/epidermis. Sebaceous glands secrete sebum which helps moisturise hair shaft and the surface of the skin. Sebaceous glands are most commonly found on the face.
Types of Hair
Lanugo, very thin, soft, usually unpigmented hair that covers the unborn or newborn human.
Vellus hair, the short, fine, “peach fuzz” body hair that grows in most places on the human body in both sexes. It covers most of the body during childhood.
Terminal hair, longer, coarser, thicker and darker fully developed hairs. The conversion from vellus to terminal is stimulated by androgenic hormones during puberty.
Arrector Pili muscle
Tiny muscles attached to the root of the hair. When they are relaxed, the hair lays flat against the surface of the skin, but when the muscle contracts it forces the hair to stand (depending on how heavy the hair is). This functional helps with thermo-homeostasis. Erect hair shafts trap air close to the surface of the skin which helps insulate the skin, helping the body stay warm. On the other hand, when the hair shafts lay flat it increases air-flow around the skin which helps cool down the skin.
Hair Cuticle Structure
The hair has a tile-like cuticle structure which helps for soils to naturally move down the cuticle. Sebum produced by the sebaceous glands get dispersed onto the cuticle and the tile-like structures help the sebum naturally flow down the cuticle from the root (where the sebum is produced) to the tips.
These tiles can get easily damaged by changes in pH, physical abrasion (heavy towelling) and chemical damage. When these hair cuticles are damaged, it feels rougher, frizzier and dryer.
Hair Shaft Structure
- The medulla is the innermost layer and is composed of cells that are filled with air.
- The cortex is the middle layer and is composed of cells that contain keratin, a protein that gives strength and flexibility to the hair.
- The cuticle is the outermost layer and consists of overlapping scales that protect the inner layers of the hair.
Hair Care Product Types
Shampoo
The first ‘shampoos’ were not shampoos at all, but simple soaps. Any cleansing agent which could remove debris was considered suitable to be used on the hair, but as the cosmetic market took on a prominent position, the differences between washing up liquid and body soap were established. Later, the cosmetics industry also distinguished between cleansing agents for the body and the hair – although they still largely work in the same way.
A shampoo is simply a product designed to cleanse the hair. There are benefits of distinguishing between body cleansers and hair cleansers as additional ingredients designed specifically for the hair could be targeted, for example anti-dandruff shampoos.
Shampoos have now further diversified into “shampoos for curly hair”, “for dry hair”, “for damaged hair”, “for coloured hair” etc. The only differences between these differential shampoo types is the active ingredients added – but the base formulations are largely the same.
Shampoo products attribute their cleansing power predominantly to anionic surfactants which help remove substrates from the hair shaft.
Conditioner
Conditioners are almost the opposites of shampoos. Whilst shampoos try to strip away substances from the hair, conditioners add in the ‘good stuff’ the shampoos have stripped away.
Shampoos are non-discriminative when it comes to cleansing, meaning they will cleanse everything they can away – even the healthy sebum which helps lubricate and keep the hair strands in good condition. To counter-act this ‘over-strippping’, conditioners are used subsequently after shampooing.
Unlike shampoos which contain primarily anionic-surfactants, conditioners contain cationic surfactants which adhere to the hair shaft and remain there until the next shampooing.
Conditioners are very important in hair care routines and frequently sold as a duos alongside shampoos. Technically, more claims can be made about conditioners than shampoos due to their longer lasting effects on the hair.
Dry shampoo/oil control agents
Dry shampoos are relatively new products to the hair care market compared to the other product types. They are designed to prolong the period between shampooing and give the appearance of fresher looking hair.
Overtime, sebum, oils and sweat build up on the scalp which later migrate down the hair shaft leading to a ‘greasy’ appearance. This is not a desirable look, so adsorbents are used to ‘soak up’ the excess oils and mattify the hair leaving a fresher looking hair-do.
This is however only a temporary solution and often only prolongs the wash-routine’s schedule by 1 or 2 days. A buildup of absorbents on the scalp and hair can also look unpleasant if too much is used.
These products are commonly applied in an aerosol form, but can also be found as powders directly applied to the scalp.
Ingredients in Hair Care Products
Cleansing Agents in hair care products
Surfactants are the main cleansing agents in the cosmetics industry. The most effective surfactants are anionic surfactants. An example of a commonly used surfactant is sodium lauryl sulfate, depicted here.
Untreated human hair has a strongly negative surface charge. Carboxyl groups of glutamine and aspartic acid and sulfonic acid groups in the hair are responsible for this property. Anionic surfactants are negatively charged, similar charges repel, so applying anionic surfactants will be attracted to the non-ionic (no charge) and cationic (positively charged) impurities, which are then removed upon rinsing the hair.
This is a very effective way of cleansing the hair, however, anionic surfactants have a reputation of stripping the hair, so many people opt for milder surfactants.
Conditioning Agents in hair care products
Conditioning agents are ingredients which help condition and smooth the hair shaft. The main conditioning agents used are cationic surfactants. Cetearyl alcohol is commonly used in conditioners, depicted here.
Because hair has a negative charge, it is attracted to positive molecules. Cationic surfactants have a positive charge, therefore, they form ionic bonds with the hair, making the molecules “stick” to the hair.
This adherence to the hair helps to protect the hair from damage, reduce friction (smoothes) and provide a lustrous shine to the hair.
Antifungal agents in hair care products
Dandruff is caused by a yeast like fungus (malassezia) that feeds on oils on the scalps of most adults. This is a naturally occurring fungus, but if the populations of these fungi grow too much they can cause an itchy, dry scalp.
The main antifungal ingredients are zinc pyrithione and selenium sulphide. Other ingredients are often used to manage dandruff such as salicylic acid.
Curling agents in hair care products
To achieve good curl-formation, it’s important to make sure that the cuticle is well hydrated, charges between strands are minimised and the hair is not overly weighed-down with oils.
Getting this balance right can be a formulation challenge for many brands. Cationic surfactants are used to reduce static forces between strands and oils are used to reduce friction between strands – it’s important to use oils with a low molecular weight so that the hair is not overly weighed down.
Formulation of Hair Care Products
Shampoo
Ingredient | Maximum concentration (% w/w) |
Anionic surfactant | 30 |
Amphoteric surfactants | 20 |
Non-ionic surfactants | 15 |
Hair conditioning agents | 15 |
Additional ingredients (UV filters, pearlescent agents, opacifying agents) | 10 |
Thickeners | 10 |
Cationic surfactants | 5 |
Parfum | 2 |
Preservatives, antimicrobials | 1.5 |
Chelating agents | 0.5 |
Aqua | to 100 |
Ingredient types and functions in shampoo preparations
Anionic Surfactants – 30%
These surfactants are the primary cleaning agents in shampoos. They create foam and help remove dirt, oil, and product buildup from the hair and scalp. Examples: Sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES)
Amphoteric Surfactants – 20%
These surfactants help to stabilise the foam produced by anionic surfactants and provide mildness to the formulation, making the shampoo gentler on the scalp. Examples: Cocamidopropyl betaine, lauryl betaine.
Non-ionic Surfactants – 15%
Non-ionic surfactants enhance the cleaning efficiency and help in emulsifying oils and dirt without creating a lot of foam. They also contribute to the overall mildness of the shampoo. Examples: Decyl glucoside, lauryl glucoside.
Hair Conditioning Agents – 15%
These agents improve the manageability, softness, and shine of the hair. They help in reducing static and frizz. Examples: Silicones (dimethicone), quaternary ammonium compounds (behentrimonium chloride).
Additional Ingredients (UV filters, pearlescent agents, opacifying agents) – 10%
UV filters protect hair from sun damage, pearlescent agents give the shampoo a shimmering appearance, and opacifying agents make the shampoo opaque and visually appealing.
Examples: Benzophenone-4 (UV filter), glycol distearate (pearlescent agent), titanium dioxide (opacifying agent).
Thickeners – 10%
Thickeners adjust the viscosity of the shampoo, making it easier to apply and use. Examples: Xanthan gum, hydroxyethylcellulose.
Cationic Surfactants – 5%
These surfactants condition the hair by neutralising the negative charges of anionic surfactants, reducing static and leaving the hair smoother and easier to comb. Examples: Cetrimonium chloride, behentrimonium methosulfate.
Parfum – 2%
Adds fragrance to the shampoo, making it pleasant to use. Examples: Fragrance oils, essential oils.
Preservatives, Antimicrobials – 1.5%
These ingredients prevent the growth of microorganisms, ensuring the product remains safe and stable over time. Examples: Methylparaben, phenoxyethanol.
Chelating Agents – 0.5%
Chelating agents bind with metal ions in the water, preventing them from affecting the performance and appearance of the shampoo. Examples: Disodium EDTA, tetrasodium EDTA.
Aqua – to 100%
Water acts as a solvent, dissolving other ingredients and forming the base of the shampoo.
Conditioner
|
Ingredient |
Maximum concentration (% w/w) |
|
Oils, waxes and fats |
20 |
|
Silicones |
20 |
|
Ethanol, isopropanol (alcohol, alcohol denat., isopropyl alcohol) |
15 |
|
Amphoteric surfactants |
15 |
|
Emulsifying agents |
10 |
|
Emollients, humectants |
10 |
|
Thickeners |
10 |
|
Additional ingredients (proteins, chelating agents, pearlescent agents) |
10 |
|
Cationic surfactants |
5 |
|
Polymers, resins |
11 |
|
Parfum |
3 |
|
UV filters |
2 |
|
Preservatives, antimicrobials |
1.5 |
|
Colourants |
1 |
|
Aqua |
to 100 |
Ingredient types and functions in conditioner preparations
Oils, Waxes, and Fats – 20%
These ingredients provide deep conditioning, shine, and protection to the hair by forming a coating that locks in moisture. Examples: Coconut oil, shea butter, lanolin.
Silicones – 20%
Silicones smooth the hair cuticle, reduce frizz, and add shine. Volatile silicones evaporate quickly, leaving a light, non-greasy feel. Examples: Dimethicone, cyclopentasiloxane.
Ethanol, Isopropanol (alcohol, alcohol denat., isopropyl alcohol) – 15%
These alcohols act as solvents and can help the conditioner spread more easily through the hair. They also aid in the quick drying of the product. Examples: Ethanol, isopropyl alcohol.
Amphoteric Surfactants – 15%
These surfactants help in cleansing and provide mild conditioning properties. Examples: Cocamidopropyl betaine, lauryl betaine.
Emulsifying Agents – 10%
Emulsifiers help to mix oil and water phases in the conditioner, creating a stable formulation. Examples: Cetearyl alcohol, glyceryl stearate.
Emollients, Humectants – 10%
Emollients soften and smooth the hair, while humectants attract moisture from the air to hydrate the hair. Examples: Glycerin, jojoba oil.
Thickeners – 10%
Thickeners adjust the viscosity of the conditioner, making it easier to apply and use. Examples: Carbomer, hydroxyethylcellulose.
Additional Ingredients – 10%
Function: These include proteins to strengthen hair, chelating agents to bind metal ions, and pearlescent agents to enhance the product’s appearance. Examples: Hydrolyzed keratin (protein), disodium EDTA (chelating agent), glycol distearate (pearlescent agent).
Cationic Surfactants – 5%
Function: These surfactants condition the hair by neutralising the negative charges, reducing static, and leaving the hair smoother and easier to comb. Examples: Cetrimonium chloride, behentrimonium methosulfate.
Polymers, Resins – 11%
These ingredients help to film-form and provide hold and structure to the hair. Examples: Polyquaternium-10, PVP (polyvinylpyrrolidone).
Parfum – 3%
Adds fragrance to the conditioner, making it pleasant to use. Examples: Fragrance oils, essential oils.
UV Filters – 2%
Protects hair from damage caused by UV radiation. Examples: Benzophenone-4, ethylhexyl methoxycinnamate.
Preservatives, Antimicrobials – 1.5%
These ingredients prevent the growth of microorganisms, ensuring the product remains safe and stable over time. Examples: Methylparaben, phenoxyethanol.
Colourants – 1%
Adds colour to the conditioner, enhancing its visual appeal. Examples: CI 19140 (yellow 5), CI 42090 (blue 1).
Aqua – to 100%
Water acts as a solvent, dissolving other ingredients and forming the base of the conditioner.
Dry Shampoo
Ingredient | Maximum concentration (% w/w) |
Propellants | 95 |
Ethanol (alcohol, alcohol denat.) | 30 |
Absorbents | 15 |
Silicones | 5 |
Emollients | 3 |
Anticaking agents | 2 |
Thickeners | 2 |
Hair conditioning agents | 2 |
Additional ingredients | 2 |
Parfum | 1 |
Colourants | 0.2 |
Ingredient types and functions in dry shampoo preparations
Propellants – 95%
Propellants are used to dispense the dry shampoo from the can as a fine mist. Examples: Butane, propane, isobutane.
Ethanol (alcohol, alcohol denat.) – 30%
Ethanol acts as a solvent and helps the absorbents and other ingredients spread evenly through the hair. Examples: Denatured alcohol, isopropyl alcohol.
Absorbents – 15%
Absorbents help to soak up excess oil and grease from the hair, making it look cleaner and fresher. Examples:** Rice starch, silica, aluminum starch octenylsuccinate.
Silicones – 5%
Silicones smooth the hair and reduce frizz, adding shine without weighing the hair down. Examples: Cyclopentasiloxane, dimethicone.
Emollients – 3%
Emollients soften and smooth the hair, enhancing its texture and feel. Examples: Caprylic/capric triglyceride, cetyl alcohol.
Anticaking Agents – 2%
Anticaking agents prevent the powder ingredients from clumping together, ensuring an even application. Examples: Magnesium stearate, zinc stearate.
Thickeners – 2%
Thickeners adjust the viscosity of the dry shampoo, making it easier to apply and ensuring it stays in place. Examples: Cellulose gum, xanthan gum.
Hair Conditioning Agents – 2%
These agents condition the hair, leaving it softer and more manageable. Examples:Panthenol (provitamin B5), hydrolyzed keratin.
Additional Ingredients – 2%
This category includes a variety of ingredients that provide additional benefits, such as UV protection, fragrance enhancement, or colour protection. Examples: UV filters like ethylhexyl methoxycinnamate, antioxidants like tocopheryl acetate.
Parfum – 1%
Adds fragrance to the dry shampoo, making it pleasant to use. Examples: Fragrance oils, essential oils.
Colourants – 0.2%
Adds colour to the dry shampoo, which can help blend it into the hair and cover up roots or grey hairs. Examples: CI 77499 (iron oxides), CI 77019 (mica).
Soap Shampoo/shampoo bar
Ingredient | Maximum concentration (% w/w) |
Soap base | 70 |
Ethanol (alcohol, alcohol denat.) | 30 |
Plant extracts | 10 |
Parfum | 2 |
Essential oils | 1 |
Soap Base – 70%
The soap base forms the main structure of the shampoo bar, providing the cleansing action by removing dirt and oils from the hair. Examples: Mixed sodium or potassium stearate, sodium or potassium laurate.
Ethanol (alcohol, alcohol denat.) – 30%
Ethanol helps to dissolve other ingredients, provides a preservative effect, and can help to ensure the bar dries and hardens properly. Examples: Denatured alcohol, isopropyl alcohol.
Plant Extracts – 10%
Plant extracts can provide various benefits such as moisturising, soothing, and nourishing the scalp and hair. Examples: Aloe vera extract, chamomile extract, green tea extract.
Parfum – 2%
Adds fragrance to the shampoo bar, making it pleasant to use and leaving a nice scent in the hair. Examples: synthetic fragrance compounds, natural fragrance oils.
Essential Oils – 1%
Essential oils can provide additional fragrance and therapeutic benefits such as antibacterial, antifungal, or calming effects. Examples: Lavender oil, tea tree oil, peppermint oil.
Regulation of Hair Care Products
Anti-fungal (anti-dandruff) shampoos
Cosmetics and biocides are different categories of products, and any ‘anti-bacterial’ claim would automatically make a product a biocidal product, meaning it would need to comply with both the cosmetic and biocides regulations. However, anti-dandruff products are slightly different. Even though these products are technically antifungal products, they do not claim to be ‘killing fungi’ just ‘managing dandruff’. Anti-dandruff products are classified differently across the globe.
EU/UK
In the European Union and United Kingdom, anti-dandruff products are considered cosmetics and are labelled, marketed and sold as such. The only additional requirement to placing these products on the UK market is declaring it as part of the submit cosmetic product notification (SCPN) form, as ‘anti-dandruff ingredients’ are listed on the national poisons information service (NPIS) list.
USA
In the United States, anti-dandruff products are classified as over-the-counter (OTC) products, which are non-prescription drugs you can get over the counter, but they are not cosmetics. The regulations for these products are more strict than those applicable to cosmetics.
The function of these products can be largely cosmetic, for example shampoo, however, due to the ingredients contained in the products, they fall outside of the scope of a cosmetic product.
Australia
Products with anti-dandruff claims can be cosmetics as long as the claims only refer to preventing and managing dandruff and not ‘curing’ or ‘treating’. This is very common with borderline products/claims. If these products do claim to be treating dandruff, they would be classified as therapeutic goods and regulated by the therapeutic goods administration (TGA).
Canada
In Canada, anti-dandruff products are classified as either natural health products or non-prescription drugs depending on their ingredients.
If the products contain salicylic acid, selenium sulfide or sulfur as the active ingredient(s), they are classified as natural health products. If they contain pyrithione zinc or coal tar they as active ingredient(s) they are classified as non-prescription drugs.
Claims of Hair Care Products
Free-from claims have seen a rise in popularity over the years due to the ‘clean beauty’ trends and health-conscious consumers. Scaremongering among cosmetic consumers has led to pressure within the industry for brands to cater to the newly ‘woke’ consumer who wants everything free-from.
The phrase “if you can’t put it in your mouth, don’t put it on your body” has significantly influenced how companies market cosmetics. Unfortunately, consumers’ pressures often stem from misunderstandings and a lack of science-backed arguments. Cosmetics are not meant for oral consumption, so making them safe to eat doesn’t make sense. Although cosmetics interact with the human body, their retention on the skin is very low and has been thoroughly tested for many decades. Just as you wouldn’t drink dish soap because it’s designed for cleaning dishes, consumers shouldn’t consider drinking their shampoo.
The cosmetics industry
The cosmetics industry falls under the category of “fashion” which leads consumers to have higher expectations for cosmetics over industries like chemical products (dish soap, plant fertiliser, air-fresheners).
There is a constant battle and compromise between consumer wants, safety and regulatory standards – especially in the claims sector. “Free from chemicals” was a once popular claim amongst consumers, but from a regulatory standpoint, it cannot be substantiated because every substance known to man is either a chemical.
To help mitigate the fall out between consumers and regulators and to help the industry form standards for cosmetic claims, the EU has published Commission Regulation (EU) No 655/2013 laying down common criteria for the justification of claims used in relation to cosmetic products, which is the industry standard for cosmetic claims.
Non-permitted Claims
Parabens Free
Parabens free is not a permitted claim because it denigrates other products on the market. They are listed as part of the approved preservatives list in the EU regulation and their safety has been repeatedly proven. Unfortunately, due to parabens scaremongering, many brands have decided to become ‘parabens free’.
The issue with brands going parabens free is microbiological resistance. As alternatives to parabens are used (phenoxyethanol and ethylhexylglycerin), the microbes are exposed to a limited variation of preservatives, making them more likely to develop a resistance to one preservative over a multitude of different preservatives. Subsequently, this makes the “clean beauty” trend, potentially more of a health risk than a health benefit.
Environmentally Friendly
Environment claims are very hard to substantiate due to a lack of in-vitro and in-vivo studies which would accurately represent the real world effects on our ecosystems. These claims are especially prevalent in rinse-off products such as shampoos and conditioners as the substances in those cosmetics will run-off into waterways and potentially interact with the environment.
The long-term effects of cosmetics on marine environments is still largely a mystery. It’s hard to observe the real-life effects of certain substances on such a large scale, but in-house testing and classification of ingredients suggests that cosmetic ingredients do not significantly affect marine life.
Permitted Claims
Free-from claims are typically not-permitted, unless they are intended to inform a consumer of specific preference/lifestyle choices and do not denigrate other products on the market.
An example of this is free-from alcohol in oral-care products. There are certain religions and individuals who choose not to consume alcohol, and even though you aren’t meant to swallow oral care products, unintentional consumption is often non-avoidable. So, for lifestyle choices, a free from claim is permitted.
Sulphate Free
Sulphates are typically present in cleansers (SLS, SLES) and are rather stripping. People with sensitive skin often avoid cosmetics which are stripping and opt for milder formulations. However, the preference here must be made obvious and it must ensure other sulphate products are not being denigrated. Therefore, the stand alone claims “sulphate free” should be paired with “… for a milder cleanse”.
Silicone Free
Similarly, silicones are not bad for the hair, however, many people with curly or wavy hair opt to avoid silicones in hair care products as they have a reputation of weighing the hair down and preventing curl/wave formation. Once again, these claims cannot denigrate other products on the market, so the claim “silicone free” must be matched with “… for a light-weight hair feel” or something along those lines.
Hydrating
Hair care products widely use the claim of hydration, but actually hydrating the hair would weaken the strands and cause breakage. However, one must view this claim from the consumer’s perspective. When consumers say their hair is “hydrated,” they mean it feels smooth. This smoothness is achieved through cationic surfactants, not by adding water to the formulation. Hydration claims are prevalent, and their substantiation refers to the smoothing properties of these products, not to adding water into the hair shaft.
