Hair ingredient hysteria as a marketing tool.
Most of what you believe about hair ingredients was planted by a brand that wanted you to buy a different product. Here is what the chemistry actually says — without the capslock and without the revolution.
The sulphate argument is overstated
Sodium lauryl sulphate is a surfactant. It removes oil from surfaces. At high concentrations in a low-pH formula, applied repeatedly to a depleted cuticle, it can cause damage — particularly to colour-treated or chemically processed hair. That is the accurate version of the sulphate concern. The inflated version, which the "sulphate-free" movement relies on, suggests that any sulphate in any shampoo is categorically harmful and should be avoided at all costs. This is not what the evidence supports. Ammonium lauryl sulphate and sodium laureth sulphate, which appear in most mainstream shampoos, are milder than SLS and are well tolerated by the majority of hair types when used at appropriate wash frequencies. The person with fine, straight, non-colour-treated hair who washes every two to three days is not the target of the sulphate warning. They have been caught in the crossfire of marketing copy aimed at someone else.
The silicone argument is misunderstood
Silicones were vilified in the same decade that sulphates were, and for similar reasons: a brand needed a "free-from" claim to justify a price premium, and silicones were available to be demonised. The factual concern with silicones is narrow: certain heavy, water-insoluble silicones — dimethicone being the most cited — can accumulate on the hair shaft over time if not periodically removed with a cleansing shampoo. For fine hair used with co-wash-only routines, this build-up can create a weight and lack of volume that feels like damage. That is the real issue, and it applies to a specific set of conditions. For coarser, drier, or more porous hair types, the same dimethicone provides slip, reduces breakage during detangling, and helps retain moisture — at which point the "silicone-free" claim is not a benefit but a subtraction. Water-soluble silicones (cyclomethicone, dimethicone copolyol) rinse out without any special protocol. The build-up concern does not apply to them at all.
Protein overload is real but oversold
Hydrolysed proteins — keratin, wheat protein, silk amino acids — temporarily bind to the hair shaft and fill gaps in a damaged cuticle. For hair that is highly porous, colour-treated, or heat-stressed, they provide genuine structure and reduce breakage. The problem is frequency. Hair that receives protein treatment every wash in a routine that already contains three protein-containing products will eventually become rigid, brittle, and prone to snapping — not because it has been strengthened but because it has been over-structured. Porosity is the variable. High-porosity hair tolerates and benefits from regular protein. Low-porosity hair, which does not absorb product easily, can reach saturation point quickly and tip into brittleness faster than people expect. The correction is balance — a protein treatment every two to four weeks for most hair types, with moisture-focused products in the sessions between.
Porosity as the master variable
Almost every ingredient decision in a hair routine comes back to porosity. Low-porosity hair has a tightly bound cuticle that resists product absorption; applying heavy oils or protein-rich treatments on top produces build-up rather than penetration. High-porosity hair — from bleaching, repeated heat, or natural structure — has a raised cuticle that absorbs quickly and loses moisture just as fast. The products that work on high-porosity hair (richer conditioners, sealing oils, weekly masks) are often the exact products that weigh down low-porosity hair and produce that flat, coated sensation that people mistake for too-much-product when it is actually the wrong product. Understanding which side of the porosity spectrum you are on — even approximately — is worth more than any individual ingredient claim.
Two ingredients and not fifteen
Most hair routines need two functional categories: a humectant and an occlusive. The humectant draws moisture into the cortex; the occlusive seals it in. Every other product in a routine is either redundant, addressing a specific concern that may or may not apply to you, or serving a marketing function rather than a chemical one. The brand economy depends on convincing people that their hair needs a primer, a pre-shampoo treatment, a clarifying step, a bonding mask, a leave-in, a styling cream, a serum, and a finishing oil applied in a specific order. In most cases, a well-formulated conditioner containing panthenol or glycerin followed by a light sealing oil is the entire routine. The rest is inventory.
Hair Ingredients — The Chemistry That Actually Matters
What's actually in your shampoo and what each thing does. The two debates, the proteins, the humectants, the oils — adult chemistry without the marketing wrapped around it. Four ingredient guides covering the molecules that matter.
The four ingredient guides
The Two Debates
Sulphates and silicones in a single honest piece. Both have been condemned by the same marketing logic and defended by the same peer-reviewed literature. The accurate concerns about both are narrow and conditional; the inflated versions are marketing copy. Covers: what SLS and SLES actually do, which silicones build up and which don't, and the porosity variable that determines whether any of it matters to your hair. URL: /en/hair/ingredients/the-two-debates/
Protein & Bonds
Hydrolysed proteins and bond builders together, because they are easily confused and frequently misused. One rebuilds what the hair shaft is made of; the other repairs the disulphide bonds that hold the scaffold together. Protein overload is real; so is protein deficiency. The porosity of your hair determines how often each intervention is appropriate. URL: /en/hair/ingredients/protein-and-bonds/
Humectants
Glycerin, panthenol, urea, and the rest of the moisture-attracting category. Humectants pull water from the environment into the cortex — excellent in high humidity, counterproductive in dry climates. The concentration, the climate, and the occlusive layered on top all determine whether a humectant is working for or against you. URL: /en/hair/ingredients/humectants/
Oils
Light and heavy hair oils together. Penetrating oils (coconut, argan, marula) work inside the cortex; sealing oils (castor, shea) work on the surface. The right category depends on porosity: high-porosity hair needs sealing; low-porosity hair benefits from lighter penetrating formulas. Wash cadence determines appropriate quantity. URL: /en/hair/ingredients/oils/
On ingredient hysteria as a marketing tool
Most of what people believe about hair ingredients was planted by a brand with a "free-from" claim to justify a price premium. Sulphate-free is overstated: mild sulphates at appropriate concentrations are well tolerated by the majority of hair types. Silicone-free is misunderstood: water-soluble silicones do not build up; heavy silicones only become a problem for fine hair on co-wash-only routines.
Porosity as the master variable
Almost every ingredient decision — which oil to use, how often to apply protein, whether humectants are helping or hindering — comes back to porosity. Low-porosity hair resists absorption and builds up quickly. High-porosity hair absorbs fast and loses moisture just as fast. Understanding even approximately which side of that spectrum you are on is worth more than any single ingredient claim on a product label.
The two-ingredient principle
Most hair routines need two functional categories: a humectant to draw moisture in, and an occlusive to seal it. Everything else is either addressing a specific concern or serving a marketing function. A well-formulated conditioner followed by a light sealing oil covers the majority of routine needs for the majority of hair types.
Also in the hair chapter
Hair Type — texture, density, porosity, and curl pattern sorted by the head you actually have. URL: /en/hair/hair-type/.
Hair Concern — breakage, dryness, thinning, scalp irritation and the diagnostics that tell you which protocol to use. URL: /en/hair/hair-concern/.
Care & Routine — wash cadence, conditioner pairing, leave-ins, oils. URL: /en/hair/routine/.
