Hair Care Glossary: Terms From Bond Builder to Volumizer
Silicones, porosity, co-washing, heat protection: the hair-care glossary explains the key terms clearly and honestly — with links to matching guide articles.
- Balayage
- A freehand coloring technique in which lightened strands are painted into the hair for a sun-kissed effect. The transition at the roots stays soft, so regrowth is less visible than with all-over color. Like any lightened hair, balayage needs extra moisture and UV protection to keep the tone from going dull. →
- Build-up
- Residue from styling products, hard-to-rinse silicones or hard-water minerals that settles on the hair layer by layer. Hair then looks dull, feels heavy and becomes hard to style, and care products can no longer work properly. An occasional deep cleanse with a clarifying shampoo removes the deposits. →
- Co-washing
- Short for "conditioner washing": hair is cleansed with conditioner only, instead of shampoo. The method is popular for dry curls because it cleans gently without stripping lipids. Since residue can accumulate over time, an occasional clarifying shampoo is part of the routine. →
- Cortex
- The fibrous layer inside the hair that makes up most of the hair shaft. It consists mainly of keratin and determines the hair's elasticity, strength and color. Coloring and bleaching change the hair right here — which is why chemically treated hair often feels different. →
- Cruelty-free
- A label for cosmetics developed and produced without animal testing. Independent certifications such as Leaping Bunny, which audit the entire supply chain, offer reliable guidance. Cruelty-free does not automatically mean vegan: a product not tested on animals can still contain animal-derived ingredients. →
- Curl types (2a–4c)
- A widely used system for classifying hair texture: type 2 (a–c) covers waves, type 3 curls, type 4 tight coils — the higher the number and letter, the more defined the pattern. The tighter the curl, the drier the hair tends to be, because sebum travels down the spiral less easily. Knowing your type helps with product choice, but it's only a guide: many heads carry several patterns at once. →
- Cuticle
- The outermost layer of the hair: flat cells overlapping like roof tiles that protect the hair shaft. When it lies flat, hair shines and feels soft; when it's roughened — by heat, friction or coloring — hair looks dull and tangles more easily. Acidic-to-neutral care, cool rinsing and sealing products help the cuticle lie down. →
- Frizz
- Stray, kinked strands that make hair look uneven and puffy. Hair is hygroscopic: in humid air it absorbs water, swells and loses its smooth shape — especially when the cuticle is roughened. Moisturizing care, sealing oils and low-friction drying visibly keep frizz in check. →
- Glycerin
- A well-established humectant that attracts water and binds it in the hair. It makes dry hair more supple and supports the bounce of curls. In very dry air, glycerin should be combined with sealing care so the bound moisture stays in the hair. →
- Gray blending
- A coloring technique that doesn't fully cover gray hair but blends it softly into the natural color — for example with fine highlights or sheer glosses. Regrowth looks more natural, and the transition to embracing gray happens gradually. Ideal for anyone who wants to show their gray without a hard reset. →
- Hair breakage
- When hairs snap mid-shaft instead of shedding at the root — visible as short strands of uneven length and white break points. The usual causes are heat, chemical treatments, friction or too much pulling while brushing and styling. Unlike natural shedding, breakage is a care issue: gentle handling and the right protein-moisture balance help prevent it. →
- Hair density
- The number of hairs per area of scalp — how many hairs you have, not how thick each strand is. High density makes hair look full even when the individual strands are fine. Hair density and strand thickness are often confused, but they call for different care and styling strategies. →
- Hair follicle
- The small pocket in the scalp where the hair is formed and anchored. Each follicle independently cycles through natural growth, transition and resting phases. The follicle's shape and size determine whether a hair grows straight or curly, fine or coarse. →
- Hair mask (deep conditioning)
- An intensive treatment with more concentrated conditioning agents than a regular conditioner. It works for a few minutes and leaves dry or stressed hair noticeably softer — leaving it on overnight adds little. As a rule of thumb, about one mask per week is enough for normal hair; a mask doesn't replace conditioner, as the two do different jobs. →
- Hair porosity
- Describes how readily hair absorbs and releases moisture — depending on how tightly the cuticle lies flat. Low-porosity hair takes in products slowly and prefers lightweight formulas; high-porosity hair (often bleached or damaged) absorbs quickly but loses moisture just as fast. Knowing your porosity makes choosing proteins, moisture and sealing care far more precise. →
- Hair thickness (strand diameter)
- The diameter of an individual hair strand — from fine to medium to coarse. Fine hair is quickly flattened by heavy products, while coarse hair tolerates richer care. A simple check: if a single strand is barely noticeable between your fingers, it's on the fine side. →
- Heat protectant
- A spray or cream applied before blow-drying, flat irons or curling wands. Film-forming ingredients slow the transfer of heat into the hair and reduce friction — they lessen heat damage but don't prevent it entirely. Good to know: wet hair is far more heat-sensitive than dry hair, so always pre-dry well before using hot tools. →
- Hydrolyzed proteins
- Proteins (e.g. from wheat, rice or silk) broken down into smaller fragments so they can act on the hair. Very small fragments can enter the hair shaft and support elasticity and bounce; larger ones form a smoothing film on the surface. Too much makes hair stiff and straw-like — balance with moisturizing care is key. →
- INCI
- The International Nomenclature of Cosmetic Ingredients — the standardized ingredient list on every cosmetic product. Ingredients appear in descending order of concentration; Latin plant names with "Oil" or "Extract" mark botanical ingredients. Complicated-sounding names aren't automatically bad: Sodium Cocoyl Glutamate, for example, is a mild coconut-based surfactant. →
- Keratin
- The structural protein that hair mostly consists of. Its fiber structure with sulfur bonds gives hair strength and elasticity. Heat, UV radiation and chemical treatments can damage keratin — wet hair is significantly more vulnerable than dry hair. Products with hydrolyzed keratin can smooth the hair surface and make hair feel stronger. →
- Leave-in
- Care that stays in the hair after washing instead of being rinsed out — as a spray, cream or serum. Leave-ins condition throughout the day, ease detangling and protect lengths from friction and dryness. Layering rule of thumb: lightest to heaviest texture — water-based leave-in first, then cream, oil last. →
- Lipid replenishment
- Deliberately giving back the lipids (oils and fats) that washing removes from hair and scalp. Oils, butters and conditioning agents wrap the hair protectively, hold moisture in and keep it supple. Dry hair and hair that gets washed often especially need good lipid replenishment. →
- Moisturizing care
- Care that brings water into the hair and keeps it there — using humectants such as glycerin or panthenol plus sealing ingredients like oils. Well-moisturized hair feels supple, shines and is easier to style. Dry, frizzy or stressed hair benefits from it most. →
- Nature-based
- Describes cosmetics whose formulas are built mainly on botanical or naturally derived ingredients. Terms like "nature-based" or "natural" are not legally protected — unlike certified natural cosmetics carrying seals such as NATRUE or COSMOS. Checking the INCI list and any certifications shows what's really in the bottle. →
- Panthenol
- Also known as provitamin B5 — a versatile conditioning ingredient that binds moisture and leaves hair supple. It can penetrate the hair shaft, improves combability and gives fine hair a little more grip and body. In scalp care, panthenol is valued for its pleasantly soothing skin feel.
- Parabens
- A group of preservatives that protect cosmetics from germs and mold. In the EU they are permitted within defined maximum concentrations; some individual parabens are banned. Many brands nevertheless leave them out and advertise "paraben-free" — in which case alternative preservative systems take over product protection.
- Phthalates
- Chemical plasticizers that used to appear in cosmetics, for example as solvents in fragrance blends. Several phthalates are banned from cosmetics in the EU. "Phthalate-free" is therefore mainly a transparency promise — signaling that hidden sources such as fragrance mixtures avoid them too.
- Plopping
- A drying technique for curls and waves: wet, product-loaded hair is wrapped upside down in a cotton T-shirt or microfiber towel. The curls dry scrunched and in shape — encouraging defined curl clumps and reducing frizz. After 15–30 minutes the wrap comes off and the hair finishes drying in the air or with a diffuser. →
- REJUVENIQE® Oil
- MONAT's botanical signature oil — a blend of more than a dozen plant oils built around Abyssinian oil (Crambe Abyssinica Seed Oil). It wraps the hair in an exceptionally lightweight, non-greasy film, smooths the surface and adds shine and softness without weighing hair down. Use it as a pre-wash treatment or drop by drop as a finishing touch on the ends. →
- Rinse-off conditioner
- Care products such as conditioners that are rinsed out after a short time. They smooth the cuticle, make detangling easier and leave hair soft without weighing it down long-term. Apply them to lengths and ends, not the roots. →
- Sebum
- The natural skin oil produced by glands at every hair follicle. It protects the scalp and roots, keeps them supple, and is why hair starts to look "greasy" over time. How much sebum is produced is mainly down to hormones and genetics — frequent washing does not "train" the scalp to produce less. →
- Silicones
- Film-forming ingredients (e.g. dimethicone) that coat the hair and instantly deliver shine, smoothness and easy combing. They don't "suffocate" hair — but hard-to-rinse types can accumulate as build-up, especially in sulfate-free routines. Water-soluble silicones rinse out easily; those avoiding them entirely find a similar feel in lightweight plant oils such as Abyssinian oil. →
- Split ends
- Split hair ends that form when the protective cuticle at the tip has worn away and the hair fiber frays apart. Once split, ends can't be sealed back together — only trimmed off; care products can merely smooth and seal the tips visually. Regular trims, minimal heat and gentle brushing are the most effective prevention. →
- Squish to condish
- A conditioning technique for curls and waves: conditioner is scrunched into very wet hair together with plenty of water — with audibly "squishy", scooping motions toward the scalp. Water enters the hair along with the conditioner, and curls form into defined clumps. Depending on hair type, you then rinse only briefly or not at all. →
- Static (flyaways)
- Flyaway hairs that stand on end when friction — from hats, wool scarves or brushing — charges the hair electrically. In dry winter air the charge can't dissipate; identically charged hairs repel each other and lift away from the head. Moisturizing care, leave-ins and a drop of oil discharge the static and settle the hair back down. →
- Sulfates
- Strongly foaming cleansing agents in many shampoos, such as sodium lauryl sulfate (SLS) and the milder sodium laureth sulfate (SLES). They cleanse thoroughly but can strip too many lipids from dry, curly or color-treated hair. Sulfate-free shampoos rely on milder surfactants like coco-glucoside — they foam less but still cleanse reliably. →
- Surfactants
- The cleansing agents in shampoos: their molecules bind oil to water so sebum, sweat and product residue can be rinsed away. They range from strongly cleansing sulfates to mild sugar- and amino-acid-based surfactants such as coco-glucoside or sodium cocoyl glutamate. Which strength fits depends on your scalp, hair type and washing frequency. →
- Telogen phase
- The natural resting stage in a hair's life cycle: after the growth phase (anagen) and a short transition (catagen), the follicle rests for a few months before the hair sheds and a new one grows in. Since every follicle follows its own rhythm, shedding around 50–100 hairs a day is normal. Life stages such as the months after giving birth can temporarily shift more follicles into the resting phase at once. →
- Vegan cosmetics
- Cosmetics made without animal-derived ingredients — no beeswax, animal-sourced keratin, lanolin or silk, for example. Vegan is not the same as natural cosmetics: a vegan product can contain synthetic ingredients, and certified natural cosmetics may use animal-derived materials like beeswax. "Vegan" alone also says nothing about animal testing — that's what cruelty-free certifications are for. →
- Yellow tinge (brassiness)
- An unwanted yellowish cast in gray, white or bleached hair. It develops through UV light, product residue, minerals in the water or environmental exposure — without melanin there is no pigment to mask the discoloration. Purple shampoos with violet pigments visually neutralize yellow based on the complementary-color principle. →
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