Active Ingredient
An ingredient included in a cosmetic formulation to provide a particular functional or cosmetic benefit, such as hydration, exfoliation, antioxidant support or improving the appearance of skin or hair.
LEARNING HUB
Cosmetic Glossary
Simple explanations of the ingredients, technologies and scientific terms used in modern skincare and haircare.
Explore clear, consumer-friendly explanations of cosmetic ingredients, formulation terminology, skin and hair biology, and the science behind Micellar Cosmetics™.
A
Adenosine
A naturally occurring molecule involved in cellular signalling and energy biology. In skincare, adenosine is used in formulations designed to support smoother-looking, healthier and more resilient skin.
Alpha Arbutin
A cosmetic ingredient used in pigmentation-focused skincare. Alpha arbutin helps reduce the appearance of uneven skin tone by influencing pathways involved in melanin formation.
Amino Acids
Small organic molecules that act as the building blocks of proteins. Amino acids are important components of skin and hair proteins and can also contribute to hydration and conditioning within cosmetic formulations.
Antioxidant
A substance that helps limit oxidative reactions caused by reactive molecules such as free radicals. Antioxidants are widely used in skincare and haircare to help protect ingredients and support the skin and hair against oxidative stress.
ATP — Adenosine Triphosphate
The primary molecule cells use to store and transfer usable energy. ATP supports energy-dependent biological processes including cellular maintenance, repair, protein synthesis and renewal.
B
Barrier Function
The skin’s ability to limit excessive water loss while helping protect the body from environmental exposure. Healthy barrier function depends strongly on the structure and lipid composition of the outermost layers of the skin.
Beta-Glucan
A naturally derived polysaccharide used in cosmetic formulations for its moisturising, conditioning and skin-soothing properties. Beta-glucan can help support hydration and the appearance of a healthy skin barrier.
Betaine
A naturally occurring osmolyte commonly used as a humectant and conditioning ingredient. Betaine helps skin and hair retain moisture and can improve the sensory feel of cosmetic formulations.
Bioavailability
The extent to which an ingredient becomes available at its intended site of action. In topical formulations, bioavailability can be influenced by factors including ingredient solubility, formulation structure, stability and interaction with the skin.
Biodegradable
Describes a material capable of being broken down by microorganisms into simpler substances under appropriate environmental conditions. The rate and extent of biodegradation depend on the material and surrounding conditions.
Bioenergetics
The study of how living cells produce, transfer and use energy. In skin and hair biology, bioenergetics includes mitochondrial energy production and the ATP-dependent processes required for normal cellular function, maintenance and renewal.
Botanical Extract
A preparation derived from plant material and incorporated into a cosmetic formulation. Botanical extracts may contain naturally occurring compounds such as polyphenols, flavonoids, sugars and other plant-derived constituents.
C
Cellular Energy
The usable energy required for cells to carry out biological processes. Much of this energy is produced by mitochondria and transferred through ATP to support functions such as maintenance, repair, synthesis and cellular renewal.
Cellular Senescence
A biological state in which a cell permanently stops dividing while remaining metabolically active. Senescent cells can accumulate with age and are increasingly studied for their role in tissue ageing and age-related biological change.
Ceramides
Lipid molecules naturally present in the skin’s outer barrier. Ceramides help organise the lipid structure between skin cells, reducing excessive moisture loss and supporting healthy barrier function.
Clean Beauty
A widely used beauty-industry term generally associated with ingredient transparency, responsible formulation and avoidance of ingredients considered unnecessary or undesirable. There is no single universally accepted regulatory definition of “clean beauty.”
Coenzyme Q10 — CoQ10
A naturally occurring antioxidant and an important component of mitochondrial energy production. Coenzyme Q10 participates in the cellular processes involved in generating ATP and is used in cosmetic formulations for antioxidant and skin-conditioning applications.
Collagen
A structural protein that provides strength and support to connective tissues, including the dermis. Changes in collagen amount, organisation and quality contribute to visible changes associated with skin ageing.
Comedogenic
A term used to describe the potential of a substance or formulation to contribute to blocked pores or comedones. Whether a finished product is comedogenic depends on the complete formulation rather than any single ingredient alone.
Creatine
A naturally occurring compound involved in cellular energy buffering. Through the creatine–phosphocreatine system, it helps cells rapidly regenerate ATP when energy demand increases.
Cruelty-Free
A term generally used to indicate that a cosmetic product or brand does not use animal testing within its stated development process. Standards and certification requirements can differ between organisations and markets.
D
Dermis
The layer of skin beneath the epidermis. It contains connective tissue, collagen, elastin, blood vessels, nerves, glands and structures associated with hair follicles, providing mechanical and biological support to the skin.
Delivery System
The formulation structure or carrier used to incorporate and present cosmetic ingredients to the skin or hair. Delivery systems can influence ingredient solubility, stability, distribution, sensory properties and availability within a topical formulation.
Dual-Route Delivery
A formulation strategy that considers more than one potential pathway for topical ingredient distribution, including movement across or between cells of the outer skin and entry through follicular openings associated with hair follicles.
E
Ectoine
A naturally occurring extremolyte produced by certain microorganisms to help protect themselves under environmental stress. In skincare, ectoine is used for its moisturising, conditioning and skin-protective properties.
Emollient
An ingredient that softens and smooths the skin by improving surface lubrication and filling spaces between superficial skin cells. Emollients can also improve the feel and spreadability of cosmetic formulations.
Encapsulation
A formulation technique in which an ingredient is enclosed within or associated with a carrier structure. Encapsulation can assist with properties such as ingredient solubility, stability, compatibility and controlled presentation within a formulation.
Epidermis
The outer cellular layer of the skin. The epidermis contains several layers of cells and forms the interface between the body and the external environment, with the stratum corneum forming its outermost barrier.
Exfoliation
The process of removing or loosening dead cells from the skin surface. Exfoliation may be achieved physically or through ingredients such as alpha hydroxy acids, beta hydroxy acids and polyhydroxy acids.
F
Fermentation
A biological process in which microorganisms such as bacteria or yeast transform substances into new compounds. In cosmetic formulation, fermentation can be used to produce or modify ingredients and create preparations containing metabolites, peptides, organic acids and other beneficial components.
Fermented Ingredient
An ingredient produced or modified through fermentation using microorganisms such as bacteria or yeast. Fermented cosmetic ingredients may contain a complex mixture of metabolites and other compounds and are commonly used in formulations designed to support conditioning, hydration and skin or scalp comfort.
Ferulic Acid
A plant-derived phenolic antioxidant naturally present in the cell walls of many fruits, grains and vegetables. In cosmetic formulations, ferulic acid is used for its antioxidant properties and is often combined with other antioxidant ingredients.
Follicle
A specialised structure within the skin associated with the growth of hair. Follicles extend from the skin surface into deeper tissue and contain multiple cell types involved in hair formation, growth cycling, pigmentation and interaction with surrounding skin structures.
Follicular Delivery
A topical delivery pathway in which formulation components enter the openings of hair follicles. Follicles can act as local reservoirs for applied substances, making follicular pathways an important consideration in formulations intended for the scalp and hair-bearing skin.
Free Radicals
Highly reactive atoms or molecules containing an unpaired electron. When produced in excess, free radicals can contribute to oxidative stress and damage cellular components such as lipids, proteins and DNA.
G
Geroprotective
A term used in ageing research to describe strategies or compounds investigated for their potential to influence biological processes associated with ageing. In cosmetic science, the concept is increasingly relevant to formulations targeting mechanisms linked with visible skin ageing and long-term skin function.
Gluconolactone
A polyhydroxy acid, or PHA, used in skincare for gentle exfoliation, moisturisation and skin conditioning. Its relatively large molecular structure generally makes it milder than many traditional alpha hydroxy acids.
Green Micellar™ Technology
Micellar Cosmetics™ formulation technology based on low-viscosity micellar and microemulsion structures designed to incorporate diverse cosmetic ingredients within lightweight, water-based formulations. The technology is used across Micellar Cosmetics™ skincare and haircare products.
H
Hair Follicle
A complex mini-organ within the skin that produces the hair fibre. Hair follicles contain specialised epithelial, connective-tissue and pigment-producing cells and repeatedly cycle through phases of active growth, regression and rest.
Hair Growth Cycle
The repeating biological cycle through which a hair follicle passes. The principal phases are anagen, the active growth phase; catagen, the regression phase; telogen, the resting phase; and exogen, when the existing hair fibre is released.
Hair Shaft
The visible fibre produced by a hair follicle and extending above the skin surface. The hair shaft consists mainly of keratinised cells organised into structural layers including the cuticle, cortex and, in some hairs, the medulla.
Humectant
An ingredient that attracts and helps retain water. Humectants are commonly used in skincare and haircare to support hydration and can include substances such as glycerin, propanediol, sodium PCA, sodium lactate and betaine.
Hydration
The amount and availability of water within skin or hair. Maintaining adequate hydration supports skin flexibility, comfort and barrier function and can improve the softness and manageability of hair.
Hydrolysed Protein
A protein that has been broken into smaller peptides and amino-acid-containing fragments through hydrolysis. Hydrolysed proteins are used in cosmetic formulations for conditioning and film-forming effects and can improve the feel and appearance of skin or hair.
I
INCI
International Nomenclature of Cosmetic Ingredients. INCI is the standardised naming system used to identify cosmetic ingredients on product ingredient lists, helping provide consistency across products and international markets.
Inflammation
A biological response of tissues to injury, irritation, infection or other forms of stress. Short-term inflammation forms part of normal defence and repair, while persistent or excessive inflammatory activity can contribute to changes in skin and scalp condition.
Intercellular Delivery
A topical pathway involving movement through the lipid-rich spaces between cells of the stratum corneum. It is one of the principal routes considered when studying how substances applied to the skin interact with and move through the outer barrier.
Isoamyl Laurate
A lightweight ester used as an emollient and formulation ingredient in skincare and haircare. It provides slip and spreadability while contributing a light, non-heavy sensory feel and can also help incorporate oil-soluble materials into formulation systems.
K
Keratin
A family of strong structural proteins found in skin, hair and nails. Hair fibres are composed predominantly of keratin, while different forms of keratin also contribute to the structure and protective function of the epidermis.
Keratinocyte
The predominant cell type of the epidermis. Keratinocytes originate in deeper epidermal layers and gradually mature as they move towards the skin surface, ultimately contributing to formation of the protective stratum corneum.
L
Lactobionic Acid
A polyhydroxy acid, or PHA, used in skincare for gentle exfoliation, hydration and conditioning. Its relatively large molecular structure contributes to a mild exfoliating profile, making it useful in formulations designed for regular or gentle resurfacing.
Lactic Acid
An alpha hydroxy acid, or AHA, used in cosmetic formulations for exfoliation, moisturisation and pH adjustment. Lactic acid also occurs naturally as part of the skin’s natural moisturising factor.
Leave-On Treatment
A cosmetic product designed to remain on the skin, scalp or hair after application rather than being rinsed away. Serums, SkinMists and HairMists are common examples of leave-on treatment formats.
Lipid Barrier
The organised mixture of lipids surrounding cells within the outermost skin layer. Components such as ceramides, cholesterol and fatty acids help reduce excessive water loss and contribute to the protective function of the skin barrier.
Longevity Cosmeceuticals
An emerging area of cosmetic science focused on supporting longer-term skin function and appearance by considering biological processes associated with ageing. The concept extends beyond correction of individual visible signs towards maintaining healthier skin function across time.
Low-Viscosity Formulation
A formulation with relatively low resistance to flow. In skincare and haircare, low-viscosity products can spread readily across skin or scalp and are particularly suitable for lightweight serums, sprays and mist-based application formats.
M
Melanin
A group of naturally occurring pigments responsible for much of the colour of skin, hair and eyes. Melanin is produced by specialised cells called melanocytes and also contributes to the skin’s natural response to ultraviolet exposure.
Melanocyte
A specialised pigment-producing cell found in locations including the epidermis and hair follicle. Melanocytes produce melanin within structures called melanosomes, which contribute to skin and hair pigmentation.
Melanocyte Stem Cell
A specialised stem-cell population associated with regeneration of pigment-producing melanocytes, particularly within the hair follicle. Changes in melanocyte stem-cell function are an important area of research in understanding hair pigmentation and greying.
Microbiome
The community of microorganisms and their associated biological environment within a particular location. The skin and scalp microbiomes include bacteria, fungi and other microorganisms that interact with the local skin environment.
Microemulsion
A thermodynamically stable, optically clear or translucent dispersion of oil, water and surface-active components. Microemulsions can form very small structured domains and are useful for incorporating ingredients with different solubility characteristics into a single formulation.
Micelle
A small organised structure formed when surface-active molecules assemble in a liquid. Micelles can contain regions with different chemical affinities, allowing them to help solubilise substances that would otherwise have limited compatibility with the surrounding liquid.
Micellar Cleansing
A cleansing approach that uses micellar structures and surfactants to help lift and disperse oils, makeup, environmental residues and other materials from the skin so they can be removed more easily.
Micellar Encapsulation
The association of cosmetic ingredients with micellar structures within a formulation. This approach can help incorporate ingredients with differing solubility characteristics and can contribute to formulation stability, compatibility and distribution.
Mitochondria
Specialised structures within cells that perform many metabolic functions, including production of much of the ATP used as cellular energy. Mitochondria also participate in redox regulation, signalling and other processes relevant to cellular function and ageing.
Mitochondrial Function
The collective metabolic activities performed by mitochondria, including energy production through cellular respiration. Healthy mitochondrial function contributes to the ability of cells to generate ATP and respond to changing metabolic demands.
Moisture Barrier
A consumer-friendly term for the structures within the outer skin that help retain water and protect against excessive moisture loss and environmental exposure. It largely refers to the barrier function of the stratum corneum.
N
Nano-Encapsulation
A formulation approach in which an ingredient is incorporated within or associated with extremely small carrier structures at the nanoscale. Nano-encapsulation can be used to address formulation properties such as solubility, stability, compatibility and ingredient distribution.
Nanocosmeceutical
A term used for technologically advanced cosmetic or cosmeceutical formulations that employ nanoscale structures or delivery systems. The term combines concepts from nanotechnology with cosmetic science and is not itself a universal regulatory product classification.
Nanocosmetics
A broad term describing cosmetic science or products involving materials, structures or formulation technologies operating at the nanoscale. Specific definitions and regulatory requirements can vary between jurisdictions.
Nano-Structured Delivery
A formulation strategy that uses very small organised structures to incorporate and distribute cosmetic ingredients. Such systems can be designed to influence properties including ingredient solubility, stability, compatibility and presentation within topical formulations.
Niacinamide
A form of vitamin B3 widely used in skincare. Niacinamide is used in cosmetic formulations designed to support skin barrier function, improve the appearance of uneven tone and texture, and maintain healthier-looking skin.
Non-Comedogenic
A term used to describe a cosmetic product formulated or assessed with the intention of minimising the likelihood of contributing to blocked pores or comedones. There is no single universal testing standard governing every use of the term.
O
Occlusive
An ingredient or formulation that forms a surface layer which helps reduce evaporation of water from the skin. Occlusives are commonly used to support moisture retention and skin barrier management.
Oxidative Stress
A biological condition in which the production of reactive molecules exceeds the capacity of antioxidant and repair systems to manage them effectively. Persistent oxidative stress can affect lipids, proteins, DNA and other cellular structures and is associated with multiple processes involved in skin and hair ageing.
P
Panthenol
A form of provitamin B5 widely used in skincare and haircare for its moisturising, conditioning and soothing properties. Panthenol helps improve hydration and can contribute to softer, smoother-feeling skin and hair.
Peptide
A short chain of amino acids linked together by peptide bonds. Peptides perform many biological functions and are used in cosmetic formulations for applications including skin conditioning, hydration and support for the appearance of firmer, healthier-looking skin.
PHA — Polyhydroxy Acid
A group of hydroxy acids used in skincare for gentle exfoliation and hydration. PHAs such as gluconolactone and lactobionic acid have relatively large molecular structures and are often used where a milder resurfacing approach is preferred.
Phyto-Polyphenol
A plant-derived polyphenolic compound. Phyto-polyphenols include substances such as resveratrol and quercetin and are widely studied for their antioxidant and biological properties.
Polyphenol
A broad family of naturally occurring compounds containing multiple phenolic structures. Many polyphenols are found in plants and are valued in cosmetic science for their antioxidant properties and their interactions with oxidative and cellular processes.
Potassium Azeloyl Diglycinate — PAD
A water-compatible derivative of azelaic acid used in cosmetic formulations targeting uneven tone, excess oiliness and skin appearance. PAD is commonly selected where formulators want some of the cosmetic benefits associated with azelaic-acid chemistry in a readily water-dispersible form.
Preservative
An ingredient used to help protect a cosmetic formulation against microbial contamination and deterioration during manufacture, storage and consumer use. Effective preservation is an important part of cosmetic product safety and stability.
Preservative-Free
A term used for formulations that do not contain ingredients added specifically as conventional cosmetic preservatives. Product microbiological safety still depends on the complete formulation, manufacturing process, packaging and appropriate stability and challenge testing.
Propanediol
A multifunctional liquid ingredient commonly used as a humectant, solvent and sensory modifier. Propanediol can help retain moisture, improve ingredient solubility and contribute to smooth spreading and a lightweight skin feel.
Probiotic Ferment
A cosmetic ingredient produced through controlled microbial fermentation. These ingredients generally contain fermentation-derived metabolites or lysates rather than functioning as live probiotic organisms and are used in formulations targeting conditioning, hydration and skin or scalp comfort.
Q
Quercetin
A naturally occurring plant flavonoid and polyphenol found in many fruits, vegetables and botanical materials. Quercetin is widely studied for its antioxidant properties and is used in cosmetic formulations as part of antioxidant and plant-derived active systems.
R
Resveratrol
A plant-derived polyphenol found naturally in sources including grapes and certain berries. Resveratrol is widely studied for its antioxidant properties and is used in cosmetic formulations designed to support protection against oxidative stress.
Retinoid
A broad term for vitamin A and vitamin A-related compounds that interact with retinoid biological pathways. Retinoids used in skincare vary considerably in strength, stability, conversion requirements and regulatory status.
Retinol
A form of vitamin A widely used in anti-ageing skincare. Retinol can influence epidermal renewal and processes associated with collagen and skin structure, helping improve the appearance of fine lines, texture and uneven pigmentation with appropriate use.
S
Senescence
A biological process associated with ageing in which cells can enter a state of long-term growth arrest while remaining metabolically active. Cellular senescence is increasingly studied for its contribution to age-related changes in tissues, including skin.
Serum
A topical cosmetic treatment format designed to deliver selected ingredients to the skin or scalp. Serums vary widely in viscosity and composition and may be water-based, oil-based, emulsified or structured using other formulation technologies.
Skin Barrier
The protective outer system of the skin, particularly the stratum corneum and its organised lipid structure. The skin barrier helps retain water while limiting excessive penetration of environmental substances and supporting overall skin resilience.
Skin Microbiome
The community of microorganisms and their biological environment associated with the skin surface. Its composition varies by body location, environment and individual factors and forms part of the wider skin ecosystem.
Skin Renewal
The continuous biological process through which new epidermal cells are generated, mature and eventually reach the skin surface where older cells are shed. The rate and organisation of this process can change with age and environmental influences.
Skinspan
An emerging concept describing the period of life during which skin maintains healthy structure, function and resilience. Skinspan shifts the focus from simply treating visible ageing towards supporting longer-term skin health and functional capacity.
Sodium Ascorbyl Phosphate
A water-soluble vitamin C derivative used in cosmetic formulations. It is valued for its antioxidant properties and greater formulation stability compared with some forms of pure ascorbic acid.
Sodium Lactate
The sodium salt of lactic acid and a naturally occurring component of the skin’s natural moisturising factor. In cosmetics, sodium lactate is widely used as a humectant to help attract and retain moisture.
Sodium PCA
A highly water-attracting component related to the skin’s natural moisturising factor. Sodium PCA is commonly used as a humectant to help maintain hydration and improve skin and hair conditioning.
Solubilisation
The process of incorporating a substance that has limited natural solubility into a liquid system in a stable and usable form. Surfactants, micelles and other formulation structures can be used to improve the apparent solubility of cosmetic ingredients.
Squalane
A stable hydrocarbon emollient commonly derived from plant sources for cosmetic use. Squalane provides softness, slip and skin conditioning while typically producing a lighter sensory profile than many conventional oils.
Stratum Corneum
The outermost layer of the epidermis and the skin’s principal physical barrier. It consists of flattened, protein-rich cells surrounded by organised lipids and plays a critical role in limiting water loss and controlling interactions with the external environment.
Surfactant
A surface-active ingredient containing regions with different affinities for water and oil. Surfactants are used in cosmetics for functions including cleansing, emulsification, solubilisation and formation of organised structures such as micelles.
T
Tocotrienols
Members of the vitamin E family that are structurally related to tocopherols but contain an unsaturated side chain. Tocotrienols are lipid-soluble antioxidants used in cosmetic formulations designed to support antioxidant protection and skin conditioning.
Topical Delivery
The presentation and distribution of ingredients through products applied directly to the skin or scalp. Topical delivery is influenced by factors including formulation structure, ingredient properties, concentration, application method and characteristics of the skin surface.
Tranexamic Acid
A synthetic amino-acid derivative used in cosmetic skincare formulations targeting the appearance of uneven pigmentation and discolouration. Its cosmetic use focuses primarily on supporting a more even-looking skin tone.
Transepidermal Water Loss — TEWL
The passive movement of water from within the body through the epidermis and into the surrounding environment. TEWL is commonly used as an indicator when assessing skin barrier function, with increased water loss often associated with impaired barrier performance.
Trehalose
A naturally occurring sugar found in various organisms, where it can help protect biological structures during environmental stress. In cosmetic formulations, trehalose is used primarily for its humectant, moisturising and conditioning properties.
U
UV — Ultraviolet Radiation
Invisible electromagnetic radiation emitted primarily by the sun. Ultraviolet radiation reaching the skin is commonly divided into UVA and UVB wavelengths, both of which can contribute to biological changes in skin and cumulative sun-related damage.
UVA
The longer-wavelength portion of ultraviolet radiation that reaches the Earth’s surface. UVA penetrates more deeply into the skin than UVB and contributes to oxidative stress, pigmentation changes and structural processes associated with photoageing.
UVB
The shorter-wavelength portion of ultraviolet radiation reaching the Earth’s surface. UVB acts predominantly within the epidermis and is strongly associated with sunburn and direct ultraviolet-induced damage to cellular DNA.
V
Vitamin C
An essential nutrient and antioxidant widely used in cosmetic science. Vitamin C and its derivatives are incorporated into skincare formulations for antioxidant support and to help improve the appearance of uneven skin tone, brightness and signs associated with environmental exposure.
Vitamin E
A family of lipid-soluble antioxidant compounds that includes tocopherols and tocotrienols. Vitamin E is used in cosmetic formulations to provide antioxidant support, help protect formulation lipids from oxidation and contribute to skin conditioning.
Viscosity
A measure of a liquid or formulation’s resistance to flow. Low-viscosity products flow readily, while high-viscosity products are thicker. Viscosity influences product application, spreading, sensory feel, packaging format and suitability for sprays, mists, serums, gels and creams.
W
Water-Based Formulation
A cosmetic formulation in which water forms a major part of the continuous phase or product base. Water-based systems can provide lightweight sensory characteristics and may be structured as solutions, gels, emulsions, micellar systems or microemulsions.
Z
Zinc Oxide
An inorganic mineral used in cosmetics for applications including skin protection, opacity and pigmentation. In sunscreen products, appropriately formulated zinc oxide can function as a broad-spectrum ultraviolet filter that provides protection across UVA and UVB wavelengths.