Understanding our hair
We have hair almost everywhere on our bodies. On average, each of us has around 100,000 hairs on our heads alone. Originally, hair helped our ancestors regulate body temperature, keeping them warm in the cold and cool in the heat. Today, hair plays a much more personal role: it’s a way of expressing identity, individuality and style. But what exactly is hair, and how does it work?
What is hair made from?
Each strand of human hair is made from keratin, a strong protein also found in fingernails though in hair it forms fibres, while in nails it appears in sheets. Hair begins growing in the follicle, deep within the skin, where cells divide rapidly at the base. As new cells form, older ones are pushed upwards, stretch, and harden. Pigment-producing cells add colour via melanin - the same pigment found in skin.
Once the cells reach the top of the follicle bulb, they change shape and ramp up keratin production. Non-keratin parts break down, and the fully formed fibre emerges. Interestingly, hair remains relatively soft until it has grown about 15mm above the skin’s surface.
What makes hair different on different people?
The hair shaft is made of three parts: the cuticle, cortex and, often, the medulla.
The cuticle is the outer layer made up of overlapping scales of keratin. These scales lie flat when dry, creating a smooth surface, and lift slightly when wet. If hair is damaged, these scales may remain open, making hair porous, more prone to absorbing water, and appear dry or frizzy.
Because the cuticle is translucent, light passes through to the inner layers of the hair. If the cuticle is raised or damaged, light scatters in multiple directions, making the hair appear dull. When the cuticle is smooth and closed, light reflects evenly, giving hair its shine.
Beneath the cuticle is the cortex, which contains melanin pigments that determine hair colour. Different types and combinations of melanin produce the wide variety of hair colours we see across people. In the centre of the shaft, many hairs also contain a honeycomb-like structure known as the medulla.
Why is our hair so important to us?
In today’s world, hair is about much more than biology. It’s tied to how we see ourselves and how we express our personalities. Hair loss can affect self-esteem and confidence, which is why empathy and support around hair changes are so essential.
Hair can boost our mood and identity, whether through a new style, colour, or cut. Facial hair also plays a key role in personal grooming, allowing men to shape their appearance and express their sense of style. Whatever our hair type, texture or length, how we care for and present it can be a powerful part of our wellbeing.
Shampoos and conditioners are carefully formulated to clean and condition your hair, helping to maintain its health, manageability, and style. But behind every bottle is a blend of science, innovation, and ingredients tailored to the needs of different hair types.
Why do we need shampoo?
An average human head contains between 100,000 and 150,000 hairs, each varying in length, shape, and style. These fibres naturally trap dirt, dust, pollution, and residues from styling products like hairspray, mousse, and gel.
Your scalp also produces sebum, a natural oil secreted by sebaceous glands at the base of each hair follicle. Sebum helps protect and moisturise the scalp and hair, but it can build up and leave hair looking greasy if not washed away.
Shampoos are designed to remove this mix of oil, dirt, and product residue, while also conditioning the hair so it's easy to manage and ready for re-styling.
What we need depends on our hair type
Hair isn’t one-size-fits-all, and neither are shampoos. Normal hair may only need mild cleaning and basic control. Coloured or chemically treated hair requires deeper conditioning.
During colouring, special fatty acids are stripped from the hair surface, making hair more negatively charged and hydrophilic, which leads to increased static and dryness. These hair types benefit from shampoos designed with targeted conditioning ingredients, often positively charged, that restore balance and manageability.
What’s in a shampoo?
Shampoos are typically made from two main types of ingredients: cleansing agents known as “surfactants” and conditioning agents.
Surfactants - the cleansing power
Surfactants are the primary cleaning agents in shampoo. Rather than using just one, most shampoos use a blend of surfactants to balance cleaning, lather, mildness, and rinsability.
Surfactant molecules have two parts: a water-loving (hydrophilic) head and an oil-loving (lipophilic) tail. The tail attaches to the oil and dirt on your hair, while the head stays in the water. These molecules surround the grime, lift it from the hair, and rinse it away with water.
Surfactants are carefully selected to be mild and non-irritating, especially for the eyes and scalp.
Conditioning agents: make hair manageable
While shampoos are mainly for cleaning, most modern formulations also include conditioning ingredients that smooth and protect the hair. These include oils and long chain fatty acids and alcohols, which help detangle and smooth hair and control ‘fly-aways’. A range of conditioning ingredients are included, in different quantities, to suit different hair types and treated hair.
Conditioning ingredients in shampoos are often uncharged, unlike those in standalone conditioners. That’s because charged molecules in conditioners can interact with the negatively charged surfactants, making the product ineffective at both cleaning and conditioning.
Other useful ingredients in shampoo
Shampoos also contain additional ingredients to make them effective, stable, and enjoyable to use:
- Thickeners – control how the shampoo flows and feels in your hand
- Foam boosters and modifiers – affect how the lather forms and rinses away.
- Preservatives – prevent microbial growth and ensure shelf life
- Sunscreens – help protect hair from UV damage, as hair cannot repair itself like skin can.
A shampoo's appeal goes beyond performance. Fragrances, colourants, and pearlising agents can also enhance the experience. Perfumes, in particular, are carefully chosen not just to smell pleasant but to create a multi-sensory, enjoyable routine.
Why do we need conditioners?
Individual hairs are mainly made up of keratin, which is the same protein that creates our nails. This outermost layer of each hair strand is called the cuticle.
Under a microscope, the cuticle looks scaly because it is made from overlapping cells. A healthy cuticle will have smooth scales but the cuticle can become damaged easily and this will result in scales which lift rather than sitting flat. This can allow moisture in and result in frizzy hair which easily tangles.
Conditioners contain specifically-designed ingredients which carry a positive charge which binds to the negative charge in our hair follicles - just the same as how the positive and negative poles on two magnets will attract. These ingredients cover the cuticles, smoothing them down, meaning our hair becomes less frizzy and easier to manage.
What are the different types of conditioners?
Innovations in conditioners have allowed for a range of conditioners that serve multiple purposes including hair repair, fixing split ends, and suitability for dry or oily hair types. Different types of conditioners also help to improve different types of hair, for example a 'leave-in' conditioner may be ideal for curlier hair types as it continues to moisturise and keep curls looking smooth as it is kept on the hair.
Product innovation
As we continue to understand more about individual hair types and needs, shampoo and conditioner formulations are evolving. Scientists are developing more refined surfactants and conditioners to deliver customised results, helping everyone achieve their desired look, every time they wash their hair.
