What Is Lactic Acid?

Lactic Acid occurs naturally in milk and is also naturally present in the skin. In cosmetic formulations, it is used as a skin-conditioning, humectant, and buffering ingredient.

Lactic Acid contributes to maintaining the skin's naturally acidic environment and supports the skin's natural moisturising function. It is also used in skin-softening preparations.

Lactic Acid in Skin Care

As an alpha hydroxy acid (AHA), Lactic Acid is commonly used in skin care products designed to improve skin texture and softness. It can also act as an astringent and help adjust the pH of cosmetic formulations.

At higher concentrations, lactic acid preparations have traditionally been used for thickened areas of skin, although such uses may fall outside the scope of ordinary cosmetic claims.

Ingredient Information

INCI Name: Lactic Acid
CAS Number: 50-21-5
EINECS/EC Number: 200-018-0
Functions: Buffering, Humectant, Skin Conditioning

References

Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4). Dweck Data.

What Is Inositol?

Inositol is a naturally occurring nutrient generally classified as a carbocyclic polyol. The most common form is myo-inositol.

In cosmetic formulations, Inositol functions as an antistatic, hair-conditioning, and humectant ingredient. It is particularly relevant to hair and scalp care formulations.

Formulation Considerations

Follicusan™ is a whitish, opaque liquid that dissolves in water and, at the recommended maximum concentration of 5%, in water-alcohol mixtures containing up to 50% alcohol by weight.

When formulating with Follicusan™, a pH range of 3.5–5.5 should be avoided, as the proteins in the ingredient may precipitate within this range.

Ingredient Information

INCI Name: Inositol
Function: Antistatic, Hair Conditioning, Humectant
CAS Number: 87-89-8
EINECS/EC Number: 201-781-2

References

Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4). Dweck Data.

What Is Dead Sea Mud?

Dead Sea Mud is a mineral-rich natural mud formed from layers of clay sediments and organic material accumulated over thousands of years around the Dead Sea. The Dead Sea lies approximately 400 metres below sea level, and its high evaporation rate has resulted in a highly concentrated environment rich in mineral salts and sediments.

The mud is particularly valued in cosmetics for its purifying, cleansing and remineralising properties.

Cosmetic Applications

Dead Sea Mud is commonly incorporated into facial masks, body treatments and exfoliating products. Its mineral content and natural exfoliating properties can help remove surface impurities and excess sebum while leaving the skin feeling smoother and more supple.

In facial masks, it can be used to cleanse and condition the skin. In scrubs, the mud contributes to gentle exfoliation and can leave the skin feeling fresh and revitalised.

Hair and Scalp Care

Dead Sea Mud can also be incorporated into hair masks and shampoos. It is traditionally used to cleanse the hair, remove excess sebum and help maintain a balanced-feeling scalp.

Dead Sea Salts and Bath Products

Dead Sea salts are rich in naturally occurring minerals and are widely used in bath and body care products. They are traditionally associated with cleansing, relaxing and conditioning effects.

The original source also describes applications involving warm Dead Sea mud treatments and traditional use for various skin and joint-related conditions. Such therapeutic uses should be distinguished from cosmetic claims and require appropriate supporting evidence.

References

Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4).

What Is Bamboo Silica?

Bamboo Silica is a natural source of plant-derived silica obtained from specific bamboo stems. Bamboo exfoliants are produced from tabasheer, an exudate that forms and crystallizes within the joints of certain bamboo species.

After collection and processing, the material forms a hard white mass that can be crushed into a crystalline powder rich in mineral salts. Certain bamboo varieties contain approximately 70% silica (SiO₂) among their mineral constituents.

Cosmetic Applications

Bamboo Silica is particularly suitable for exfoliating creams and gels, where its crystalline particles help remove dead skin cells and surface debris.

Bamboo-derived silica can also provide several functional and sensory benefits in cosmetic formulations, including:

• Sebum absorption
• Mattifying effects
• Silky skin feel
• Improved application and spreadability
• Absorption of excess perspiration
• Reduced lipstick exudation
• Increased volume in mascara formulations
• Improved nail polish wear

Bamboo silica is therefore used in a variety of skin care, makeup, and nail care formulations.

Traditional Uses

Tabasheer has a long history of use in traditional Indian and Eastern medicine. It has been described as a source of hydrated silica and has traditionally been associated with remineralising applications, including those involving hair and nails.

These traditional uses should be distinguished from cosmetic efficacy claims and from the functions of bamboo silica in modern cosmetic formulations.

Ingredient Information

INCI Name: Bamboo Silica
Main Component: Silica (SiO₂)

References

Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4).

What Is Garcinia Cambogia Fruit Extract?

Garcinia Cambogia Fruit Extract is obtained from the fruit of Garcinia cambogia, also known as Gamboge Tree or Malabar Tamarind, belonging to the Guttiferae family.

The fruit is traditionally used to enhance the culinary experience of meals and is a natural source of hydroxycitric acids (HCA), which are structurally related to citric acid.

Hydroxycitric Acid

One of the principal hydroxycitric acid isomers is (-)-hydroxycitric acid. Research has investigated its role in lipid metabolism, particularly its ability to inhibit ATP-dependent citrate lyase, an enzyme involved in the conversion of citrate to oxaloacetate and acetyl-CoA.

These properties have contributed to interest in Garcinia cambogia as a botanical ingredient, although research findings should be distinguished from cosmetic efficacy claims.

Ingredient Information

INCI Name: Garcinia Cambogia Fruit Extract

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Hydrogen Peroxide?

Hydrogen Peroxide is a clear, colorless liquid used in a variety of cosmetic and personal care products. It is particularly common in hair dyes, hair bleaches, conditioners, shampoos, and rinses, as well as in tooth-whitening products.

Cosmetic Applications

Hydrogen Peroxide is primarily used as an oxidizing and antimicrobial agent.

In oxidative hair colouring, it helps form the coloured compounds responsible for the final hair colour. In hair bleaching products, its oxidizing properties contribute to the lightening process.

In oral care products, Hydrogen Peroxide can be used to oxidize stains on the teeth, supporting their whitening.

As an antimicrobial ingredient, it can inhibit or destroy microorganisms.

Other Uses

Hydrogen Peroxide also has applications outside cosmetics. The original source notes its use as an antimicrobial, oxidizing, reducing, and bleaching agent in food products. It is also used in certain antiseptic preparations.

Ingredient Information

INCI Name: Hydrogen Peroxide

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Niacinamide?

Niacinamide, also known as nicotinamide, is a water-soluble form of vitamin B3. In cosmetics, it functions primarily as a skin- and hair-conditioning agent.

It is used in a wide range of cosmetic formulations, including skin moisturizers, cleansing products, shampoos, and hair tonics.

Cosmetic Applications

Niacinamide is incorporated into formulations for its conditioning properties and is suitable for a broad range of skin and hair care products.

Its use in cosmetics has been evaluated by the Cosmetic Ingredient Review (CIR) Expert Panel, which concluded that Niacinamide and Niacin are safe when used under the current practices and concentrations in cosmetics and personal care products.

Ingredient Information

INCI Name: Niacinamide
CAS Number: 98-92-0
EINECS/EC Number: 202-713-4

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Piper Longum Fruit Extract?

Piper Longum Fruit Extract is an extract of the fruit of Long Pepper (Piper longum L.), a plant belonging to the Piperaceae family.

The fruit contains approximately 1% volatile oil, together with resin, alkaloids such as piperine and piperlonguminine, and other naturally occurring compounds.

Composition of Piper Longum Fruit

The major constituents include essential oils, mono- and sesquiterpenes, piperine, piperlongumine, piperlonguminine, pipernonaline, sesamin, and β-sitosterol.

The essential oil is a complex mixture in which caryophyllene, pentadecane, and bisabolene are among the principal constituents. Other reported components include thujine, terpinoline, zingiberine, p-cymene, p-methoxy acetophenone, and dihydrocarveol.

Traditional and Investigated Uses

Piper longum has a long history of traditional use. The original source describes its traditional use in preparations intended to support respiratory health and reports experimental investigations of its biological properties.

Studies have also investigated the essential oil and fruit-derived compounds for antifungal activity. These findings relate to specific extracts or isolated compounds and should not automatically be interpreted as cosmetic efficacy claims for every Piper Longum Fruit Extract.

Cosmetic Applications

The presence of volatile oils and bioactive botanical compounds makes Piper Longum Fruit Extract a potential ingredient for botanical and active cosmetic formulations. The composition and properties of the final ingredient depend on the plant material and extraction method used.

Ingredient Information

INCI Name: Piper Longum Fruit Extract

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Hydrolyzed Wheat Starch?

Hydrolyzed Wheat Starch is a hydrolysate of wheat starch produced through acid, enzymatic, or other hydrolysis methods. As a naturally derived ingredient, it contains wheat oligosaccharides and provides a combination of hydrating and film-forming properties.

Cosmetic Applications

Hydrolyzed Wheat Starch is used as a hair and skin conditioning ingredient. Its moisture-balancing and film-forming properties can provide several sensory and functional benefits.

In hair care formulations, it can help improve body and manageability. In skin care products, it contributes to a smoother and softer skin feel.

The combination of hydration and film formation makes Hydrolyzed Wheat Starch suitable for a range of skin and hair care formulations.

Safety

According to the original source, no adverse effects have been reported or are expected from this established hair and skin softening ingredient.

Ingredient Information

INCI Name: Hydrolyzed Wheat Starch

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Zinc Oxide?

Zinc Oxide (ZnO) is an inorganic cosmetic ingredient widely used in cosmetics and personal care products. It is also known as CI 77947 and is used as a colourant in cosmetic formulations.

The ingredient has several cosmetic functions, including colour, skin protection and UV absorption. Its applications and permitted uses depend on the regulatory requirements of the relevant market and on the physical characteristics of the Zinc Oxide used.

Cosmetic Applications of Zinc Oxide

Colourant

Zinc Oxide is used as a white colourant in cosmetic and personal care products. It can be used in products applied to areas including the lips and eye area when the applicable specifications are met.

Skin-Protecting Products

Zinc Oxide is used in skin-protecting formulations and is particularly well known for its use in products designed to protect the skin.

Sunscreen Formulations

Zinc Oxide can function as a UV filter in sunscreen formulations. Its ability to absorb and scatter UV radiation makes it an important ingredient in mineral sunscreen products.

Zinc Oxide Nanomaterials in Cosmetics

The properties of Zinc Oxide can vary depending on particle size, morphology, purity and surface treatment. For this reason, nano-sized Zinc Oxide requires specific consideration in cosmetic formulation and safety assessment.

The SCCS has evaluated specific Zinc Oxide nanomaterials for use as UV filters. The materials evaluated include nanoparticles with a purity of at least 96%, a wurtzite crystalline structure and defined particle-size characteristics.

For the evaluated materials, the median particle diameter (D50) is above 30 nm and D1 is above 20 nm.

The evaluated nanoparticles may be uncoated or coated with specific surface treatments, including triethoxycaprylylsilane, dimethicone, dimethoxydiphenylsilanetriethoxycaprylylsilane cross-polymer or octyl triethoxy silane. Other coatings require appropriate safety evaluation and should not adversely affect the relevant particle properties.

Formulation Considerations

When using Zinc Oxide in cosmetic formulations, the intended function, particle characteristics and regulatory status should be considered carefully.

For sunscreen products, particular attention should be given to whether the Zinc Oxide is used in pigmentary or nano form and whether the specific material complies with the applicable regulatory requirements.

Ingredient Information

INCI: Zinc Oxide
CAS: 1314-13-2
EINECS/EC: 215-222-5
Colour Index: CI 77947

References

Source: Handbook of Cosmetic Ingredients: Their Use, Safety and Toxicology – Anthony Dweck.

What Is Behenyl Alcohol?

Behenyl Alcohol is a long-chain fatty alcohol with a waxy, solid appearance. Fatty alcohols are widely used in cosmetics and personal care products, particularly in skin lotions and creams.

Behenyl Alcohol is typically used to modify the texture and consistency of cosmetic formulations and can contribute to a smooth, pleasant skin feel.

Cosmetic Applications

Fatty alcohols such as Behenyl Alcohol are commonly incorporated into formulations where they can contribute to:

• Consistency and viscosity
• Skin conditioning
• Texture modification
• Stability of creams and lotions

Behenyl Alcohol can therefore be useful in a variety of skin care and personal care formulations where a structured, creamy texture is desired.

Safety

The safety of Cetearyl Alcohol, Cetyl Alcohol, Isostearyl Alcohol, Myristyl Alcohol, and Behenyl Alcohol has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The panel concluded that these fatty alcohols were safe for use as cosmetic ingredients.

In 2005, the CIR Expert Panel reviewed newly available data concerning Cetearyl Alcohol and the other fatty alcohols and reaffirmed its previous safety conclusions.

Ingredient Information

INCI Name: Behenyl Alcohol

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Creatine?

Creatine is a naturally occurring nitrogen-containing organic acid produced in the human body from amino acids, primarily in the kidneys and liver. It is transported through the blood and is predominantly stored in skeletal muscle.

Creatine is also naturally present in human skin, where creatine kinase (CK) systems and creatine transporters are involved in cellular energy metabolism.

Creatine in Skin Care

Research by scientists at Beiersdorf Research and Development investigated creatine as a potential topical cosmetic ingredient for ageing skin. The research focused on the relationship between cellular energy metabolism, mitochondrial function and oxidative stress.

Studies reported that externally applied creatine was taken up by keratinocytes and increased creatine kinase activity and mitochondrial function in human epidermal cells. The research also indicated protection against oxidative and UV-induced stress under the conditions studied.

These findings support the use of creatine as a cosmetic active ingredient in formulations targeting the appearance of premature skin ageing and skin damage.

Cosmetic Applications

Creatine can therefore be considered for anti-ageing and skin-conditioning formulations, particularly products designed to support the skin's natural energy metabolism and help protect cells from environmental stress.

The reported research findings should be distinguished from therapeutic claims and considered in the context of the specific formulation, concentration and supporting evidence.

Ingredient Information

INCI Name: Creatine
Chemical Name: Glycine, N-(Aminoiminomethyl)-N-Methyl-

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Undaria Pinnatifida Extract?

Undaria Pinnatifida Extract is an extract of the brown algae Undaria pinnatifida, also known as Wakame, Sea Mustard, or Japanese Kelp. The algae belongs to the Alariaceae family and naturally grows in marine environments exposed to factors such as UV radiation, water movement, and abrasion.

Its ability to withstand these environmental conditions is associated with its content of fucoidan, a sulphated polysaccharide that contributes to the structural integrity and stability of the algae's cell walls.

Composition and Cosmetic Properties

Undaria pinnatifida contains a range of naturally occurring compounds, including:

• Proteins
• Lipids
• Micronutrients
• Vitamins
• Sugars
• Fucoidan

Fucoidan has been reported to exhibit free-radical-scavenging and hyaluronidase-inhibiting properties. These characteristics have contributed to the use of Wakame extracts as active ingredients in cosmetic skin care formulations.

Applications in Skin Care

Undaria Pinnatifida Extract is used in cosmetic formulations where skin revitalising, conditioning, and anti-ageing properties are desired.

The original source refers to a glycerin/aqueous extract marketed as Phytessence Wakame, for which supplier research reported inhibition of hyaluronidase activity and protection against the degradation of hyaluronic acid. The reported effects included reduced deterioration of skin tissue, maintenance of dermal thickness, and improved skin firmness.

Such findings describe the properties of a specific extract and should not automatically be applied to every Undaria pinnatifida extract, as composition and activity can vary according to extraction method and raw material.

Ingredient Information

INCI Name: Undaria Pinnatifida Extract

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Pyrus Malus Seed Oil?

Pyrus Malus Seed Oil is the oil expressed from the seeds of the apple, Pyrus malus L., belonging to the Rosaceae family. Apple seed oil can be obtained by cold pressing and filtration, without the use of solvents.

The oil is naturally rich in essential fatty acids and is used as a cosmetic ingredient in products such as hair conditioners, hand and body lotions, and shampoos.

Composition of Apple Seed Oil

Apple seed oil contains a high proportion of essential fatty acids.

Its principal fatty acids include:

• Linoleic acid: approximately 60%
• Oleic acid: approximately 27.5%
• Palmitic acid: approximately 7.4%
• Stearic acid: approximately 2%

The exact fatty acid profile can vary depending on the origin and processing of the oil.

Cosmetic Applications

Pyrus Malus Seed Oil is primarily used as an emollient, helping to improve the skin feel and conditioning properties of cosmetic formulations. It can be incorporated into a variety of skin care and hair care products, particularly formulations containing natural plant oils.

Ingredient Information

INCI Name: Pyrus Malus Seed Oil
CAS Number: 85251-63-4
EINECS/EC Number: 286-475-7

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5).

What Is Lactobacillus Ferment?

Lactobacillus Ferment is the product obtained through the fermentation of Lactobacillus. Lactobacillus fermentum is a Gram-positive bacterial species belonging to the genus Lactobacillus. It is commonly associated with fermented animal and plant materials and has also been identified in sourdough.

Certain strains of Lactobacillus are considered probiotic or beneficial bacteria. However, the properties and applications of a cosmetic Lactobacillus ferment depend on the specific fermentation process and resulting ingredient.

Lactobacillus Ferment in Cosmetics

Lactobacillus-derived ingredients have attracted interest in skin care and cosmetic formulations, particularly in products formulated for maintaining the condition and appearance of the skin.

Ingredient Information

INCI Name: Lactobacillus Ferment

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: Their Use, Safety and Toxicology (Dweck Books 5).

What Is Propanediol?

Propanediol is a glycol used in cosmetics and personal care products as an alternative to conventional glycols.

It can be used as an alternative to ingredients such as propylene glycol (1,2-propanediol), butylene glycol, or glycerin, depending on the formulation requirements.

Functions in Cosmetic Formulations

Propanediol can perform several functions in a cosmetic formulation, including:

• Humectant – helps attract and retain moisture.
• Solvent – helps dissolve and incorporate other ingredients.
• Emollient – contributes to skin feel and softness.
• Hand-feel modifier – can improve the sensory properties of a formulation.
• Viscosity enhancer – can contribute to the desired consistency.
• Botanical extraction and dilution – can be used during the preparation of botanical ingredients.
• Carrier for active ingredients – helps incorporate selected functional ingredients into formulations.
• Ingredient in natural esters and ethers.
• Component of natural preservative systems.

Cosmetic Applications

Because of its versatility, propanediol can be incorporated into a wide range of skin care, hair care, and personal care formulations. Its combination of humectant, solvent and sensory properties makes it useful when developing formulations that require a multifunctional glycol with a pleasant skin feel.

Ingredient Information

INCI Name: Propanediol

References

Dweck, Anthony. Handbook of Cosmetic Ingredients: Their Use, Safety and Toxicology (Dweck Books 5).

What Is Rheology?

Rheology describes the flow characteristics of liquids and the deformation of solids. In cosmetic formulations, rheological properties are particularly important for liquid and semiliquid products because they influence mixing, processing, filling, application, consistency, spreadability, and smoothness. Rheology can also affect the physical stability and biological availability of a product.

Newtonian and Non-Newtonian Flow

Cosmetic systems can generally be classified as Newtonian or non-Newtonian.

Newtonian fluids have a constant viscosity when subjected to shear, meaning that flow rate is directly proportional to the applied shear stress. Examples include water and mineral oil.

Most cosmetic products, however, exhibit non-Newtonian behaviour, where viscosity changes depending on the applied shear. This can include plastic, pseudoplastic, and dilatant flow, as well as thixotropy.

Thixotropy in Cosmetic Products

Thixotropic behaviour can be particularly desirable in topical products. For example, a cream or gel may remain in place inside a tube and not flow through the opening until pressure is applied. During application, the increased shear can make the product temporarily more fluid, allowing it to spread easily over the skin.

Once the shear is removed, the formulation can recover its higher viscosity and remain in place.

Measuring and Controlling Rheology

Rheological properties are evaluated during product development to characterise the formulation and are also important for quality control after manufacturing. Rotational and oscillatory instruments are commonly used to measure the rheological behaviour of non-Newtonian systems.

Rheology can be adjusted through the selection and concentration of viscosity-modifying agents and other formulation components. Electrolytes can also significantly affect viscosity; for example, polyacrylate-based systems can be sensitive to ions.

In emulsions, rheology depends on factors including the viscosity of the internal and external phases, phase volume ratio, particle size distribution, emulsifier system, and viscosity-modifying ingredients. Even relatively small changes in ingredient concentration or ratios can therefore produce significant changes in the final rheological properties.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Are Sticks?

A stick is a solid cosmetic delivery system cast into an elongated form. The product is applied by rubbing the stick directly onto the skin, allowing cosmetic ingredients such as fragrances, colouring agents, emollients, and pigments to be delivered.

Sticks are particularly suitable for incorporating insoluble substances, including pigments. The most common cosmetic stick products are lipsticks and antiperspirant or deodorant sticks.

Basic Types of Cosmetic Sticks

There are three main types of stick vehicles:

Wax and Oil Sticks

These are mixtures of waxes, such as beeswax or carnauba wax, and oils, such as mineral oil or castor oil. The mixture is cast into a solid form and may contain dissolved or undissolved ingredients.

Hydrophilic or Aqueous Sticks

These systems are based on water, propylene glycol, alcohol, or combinations of these solvents. They are commonly solidified using sodium stearate and can contain ingredients such as aluminium chlorohydrate for antiperspirant applications.

Silicone-Based Sticks

These sticks use a high-boiling volatile silicone, such as cyclomethicone, which is structured into a solid or gelled matrix using a fatty alcohol such as stearyl alcohol.

Clear Sticks

Clear sticks have become increasingly popular in cosmetic applications. One approach uses dibenzylidene sorbitol as a gelling agent in propylene glycol or other related polyols, producing a transparent solid stick.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Are Suspensions?

Suspensions are formulations in which insoluble particles, such as active ingredients or functional excipients, are dispersed in a liquid or semisolid medium that acts as the vehicle.

They can be used for topical application and to deliver substances to the skin. Common cosmetic examples include sun-protection products and pearlescent nail lacquers containing pigments.

Stability of Suspensions

Because suspended particles may have a different density from the surrounding vehicle, sedimentation can occur during storage. To ensure a homogeneous product during application, the particles should either remain sufficiently suspended or be readily redispersible by shaking before use.

Sedimentation can be reduced by:

• Reducing particle size
• Increasing the viscosity of the vehicle
• Developing a thixotropic system

The formulation should be designed so that any settled particles can be easily redispersed and the product provides a consistent application.

The Role of the Vehicle

The liquid or semisolid phase determines many of the application properties of a suspension. Its effect on the skin is comparable to the vehicle phase in other cosmetic formulations, such as solutions and emulsions.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Are Microemulsions?

A microemulsion is a system composed of water, oil and an amphiphile (surfactant) that forms a single, optically isotropic system. Depending on the formulation, the internal phase can consist of oil droplets dispersed in water or water droplets dispersed in oil.

The dispersed structures typically have diameters of approximately 10–200 nm, which allows microemulsions to appear optically clear or translucent. They can occur as liquid or gel-like systems.

Properties of Microemulsions

Microemulsions are generally more stable than conventional emulsions and can be used to incorporate or solubilise active substances. Their small droplet size can also support improved skin penetration and permeation of certain ingredients.

They are commonly described as ternary systems consisting of water, a lipid phase and a surfactant mixture in a specific ratio.

Surfactants and Skin Tolerance

A potential disadvantage of microemulsions is their relatively high surfactant concentration, which may increase the risk of skin irritation or sensitisation. Modern formulations may use alkyl polyglycosides, which are generally considered milder than conventional polyoxyethylene-based nonionic surfactants.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Are Hydrogels?

Hydrogels are hydrophilic gel systems consisting mainly of water or an aqueous-alcoholic mixture, together with a gelling agent. They typically contain around 85–95% water.

The gelling agent is generally an organic polymer, such as polyacrylic acid (Carbopol), sodium carboxymethylcellulose, or nonionic cellulose ethers.

Properties of Hydrogels

Hydrogels provide a light, easily spreadable texture and produce a cooling effect after application, mainly due to evaporation of the solvent. They can also provide an immediate moisturising or hydrating sensation.

Because the high water content makes hydrogels susceptible to microbial contamination, they require an appropriate preservation system.

Formulation Considerations

As water evaporates from a hydrogel applied to the skin, the remaining polymer can leave a sticky or film-forming sensation. The choice of thickener and other formulation aids therefore has an important influence on the final sensory properties.

For longer-lasting application, humectants such as glycerol (glycerin) may be incorporated to help reduce the drying effect associated with solvent evaporation. Appropriate selection and testing of the gelling agent, humectants and other adjuvants are essential for achieving the desired texture and skin feel.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Are Gels?

Gels are dispersed systems, originally liquids or solutions, that are structured to provide a consistency suitable for topical application. Unlike emulsions, gels generally do not contain two immiscible phases with opposite lyophilicity. Depending on the nature of the incorporated substances, they can be hydrophilic hydrogels or lipophilic lipogels (oleogels).

How Are Gels Structured?

The characteristic consistency of a gel is created by gelling or thickening agents, usually polymers, which form a three-dimensional network. Intermolecular forces bind solvent molecules to this network, reducing their mobility and increasing the viscosity of the system.

Properties of Cosmetic Gels

Pure gels are generally transparent, clear, or slightly opalescent. Transparency can be achieved when the ingredients are completely dissolved or present in colloidal form with particles in the submicron range.

Their light texture, appearance, and pleasant sensory characteristics make gels popular in cosmetic care products. They can also be used as a basis for more complex formulations.

Solid particles can be incorporated into gels to create stabilized suspensions, while oily lipids can be incorporated to produce hydrolipid dispersions or quasiemulsions.

References

Handbook of Cosmetic Science and Technology – André O. Barel, Marc Paye, Howard I. Maibach.

What Is Melasma?

Melasma is a pigmentation disorder characterized by increased pigmentation of the skin, most commonly appearing as symmetrical patches or macules on the face. It typically affects sun-exposed areas such as the cheeks and upper lip.

Melasma is considerably more common in women than in men and is particularly prevalent in people with higher phototypes. Major factors associated with its development include genetic influences, female sex hormones, and exposure to ultraviolet (UV) radiation.

Pathogenesis of Melasma

Histopathological findings indicate increased pigmentation throughout the epidermal layers, associated with increased melanin production and a higher number of active melanocytes.

The exact pathogenesis of melasma remains incompletely understood. Research has indicated that increased expression of α-melanocyte-stimulating hormone (α-MSH) in keratinocytes within melasma lesions may contribute to the development of hyperpigmentation.

Cosmetic and Treatment Approaches

Because UV exposure is an important contributing factor, broad-spectrum sun protection is an important part of managing the appearance of melasma.

Approaches traditionally used to address hyperpigmentation include retinoids, alpha-hydroxy acids (AHAs), and hydroquinone. Their use and regulatory status depend on the intended application and market.

For cosmetic product development, ingredients and claims should be selected carefully to ensure that the finished product remains within the applicable cosmetic regulatory framework.

References

Dermatologic, Cosmeceutic and Cosmetic Development – Kenneth A. Walters, Michael S. Roberts.

What Is the Scale-Up Process?

In cosmetic product development, the scale-up process is the transition from laboratory-scale production to manufacturing-scale production. Its purpose is to ensure that the final product maintains the same characteristics as the successfully developed laboratory sample when produced in larger quantities.

Rather than moving directly from a small laboratory batch to full-scale manufacturing, progressively larger pilot batches are produced. For example, a 100 g laboratory sample may be followed by a 1 kg batch, then a 10–20 kg batch, before moving to the final production size.

Why Is Scale-Up Important?

A formulation that performs well in the laboratory may behave differently when produced in larger equipment. Changes in mixing, heating, cooling, processing time, equipment geometry, and measurement accuracy can affect the final product.

Pilot production helps identify and correct these differences before mass production begins. If a batch does not reproduce the expected characteristics, the production process can be adjusted and repeated.

Key Factors During Scale-Up

During scale-up, the following parameters should be monitored:

• Physical characteristics and appearance
• Stability and consistency
• Manufacturing parameters
• Equipment performance
• Measurement accuracy
• Product quality

Using equipment based on the same processing technology at different scales can make the transition more predictable. Small laboratory batches can also be particularly sensitive to measurement uncertainty, as even small weighing deviations may have a significant effect on the formulation.

Documentation and Final Production

The scale-up process should be properly documented to ensure consistency and reproducibility. Analytical testing and quality checks can be performed throughout the process, while any deviations should be investigated and resolved.

Once the scale-up is successfully completed, the final batch size, manufacturing documentation, and relevant physical parameters can be established. This provides the basis for moving the cosmetic product into routine mass production.

What Is Fenugreek?

Fenugreek (Trigonella foenum-graecum) is an aromatic plant whose seeds have a long history of traditional use. The plant attracted particular scientific interest as a source of diosgenin, a naturally occurring steroidal sapogenin.

Fenugreek seeds are traditionally described as having emollient properties and have been used in various topical preparations.

Fenugreek in Cosmetics

Fenugreek seed extracts are incorporated into cosmetic formulations for applications including:

• Skin cleansing
• Skin conditioning
• Hair care
• Hair tonics
• Products targeting the appearance of hair loss

Traditional Uses and Safety Considerations

Historically, fenugreek seeds have been used in topical preparations for irritated or inflamed skin and as emollient applications. Traditional preparations have also included poultices and hot compresses.

For cosmetic product development, the intended concentration, route of exposure and safety data for the specific fenugreek preparation should be considered as part of the cosmetic safety assessment.

References

The internal and external use of medicinal plants – Anthony C. Dweck, FLS, FRSC, FRSH.

What Does “Natural” Mean?

There is no single universal legal definition of “natural” for cosmetic ingredients. This has led to different interpretations and approaches within the cosmetics industry.

A natural material can be defined as a material that is harvested, mined or collected and may subsequently undergo processes such as washing, decolorisation, distillation, fractionation, grinding, milling, separation or concentration, provided that the resulting chemical or chemicals are available and detectable in the original source material.

Natural materials may also be modified through the action of microorganisms, enzymes or yeasts to modify or increase the yield of naturally occurring materials.

Natural-Origin Materials

Naturally derived materials are produced using a natural raw material as the starting point of a chemical process. The resulting chemical may not itself occur naturally or may not be present in the original starting material.

This distinction is important when evaluating cosmetic ingredients marketed as natural or naturally derived.

Nature-Identical Materials

A nature-identical material is produced synthetically rather than necessarily from a natural starting material, but is chemically identical to a substance that occurs naturally.

Therefore, a nature-identical ingredient can have the same chemical structure as a naturally occurring substance without being obtained directly from a natural source.

ISO 16128 and Natural Cosmetics

Although the concept of “natural” is complex, the cosmetics industry has an international framework through ISO 16128.

ISO 16128-2:2017 provides approaches for calculating natural, natural-origin, organic and organic-origin indexes for ingredient categories defined in ISO 16128-1. It also provides a framework for determining the natural and organic content of cosmetic products based on their ingredients.

ISO 16128 is specifically designed for the cosmetics sector and provides definitions and criteria intended to support a more consistent approach to natural and organic cosmetic ingredients and products.

Natural Claims in Cosmetic Products

When developing or marketing a cosmetic product as natural, it is important to distinguish between natural, naturally derived, organic and nature-identical ingredients. The origin and processing of each ingredient should be considered when determining how a product can appropriately be described.

References

The internal and external use of medicinal plants – Anthony C. Dweck, FLS, FRSC, FRSH.
ISO 16128-2:2017 – Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients.

What Is Microneedling?

Microneedling is a minimally invasive transdermal delivery technique that uses very small needles to create temporary openings in the skin. These openings can facilitate the penetration of substances that would otherwise have difficulty passing through the skin barrier.

Microneedles can range from approximately 100 to 1500 μm in length, while the stratum corneum is typically around 10–30 μm thick.

Microneedling and Cosmetic Ingredient Delivery

By creating microscopic pores, microneedling can facilitate the delivery of larger molecules, including certain peptides and other hydrophilic ingredients.

The effectiveness of the technique depends partly on the mechanical properties of the skin. Skin elasticity can cause the skin to deform under pressure, potentially reducing penetration and pore formation.

Microneedling and Peptides

Research has investigated microneedling as a delivery method for cosmetic peptides. One in-vitro study evaluated solid microneedle arrays consisting of 121 needles for the delivery of acetyl hexapeptide-3 through pig ear skin.

The study reported substantially higher peptide permeation when microneedles were applied compared with untreated skin, demonstrating the potential of this approach for enhancing topical peptide delivery.

Microneedling in Cosmetic Product Development

Microneedling can therefore be considered a delivery-enhancement technology for cosmetic actives, particularly ingredients with limited ability to penetrate the skin on their own. Its use requires consideration of the ingredient, delivery system, microneedle characteristics and intended application.

References

Journal of Drug Delivery Science and Technology – Anti-aging peptides for advanced skincare: Focus on nanodelivery systems

What Are Antioxidant Peptides?

Antioxidant peptides are short chains of amino acids that can help counteract oxidative stress by donating an electron or hydrogen atom to stabilise free radicals. They may also bind metal ions, such as copper, which can be involved in biological processes associated with inflammation and skin ageing.

Oxidative stress can result from factors including mitochondrial metabolism and UV radiation. The accumulation of reactive oxygen species (ROS) is associated with signalling pathways that can affect collagen synthesis and increase the activity of matrix metalloproteinases (MMPs).

Factors Affecting Antioxidant Activity

The antioxidant activity of a peptide depends on several structural characteristics, including:

• Molecular weight: smaller peptides generally have a greater ability to donate hydrogen or electrons.
• Hydrophobicity: greater hydrophobicity may improve interaction with hydrophobic cellular structures such as biological membranes.
• Amino acid sequence: the specific amino acids and their arrangement influence antioxidant activity.

Hydrolyzed Collagen Peptides

Hydrolyzed collagen, also known as collagen hydrolysate, is produced by enzymatic hydrolysis of collagen proteins. Hydrolyzed collagen is widely used in cosmetics because of its biocompatibility, biodegradability and low toxicity when applied topically. It is also used as a moisturising ingredient for the stratum corneum.