Glossary of Cosmetic Ingredients: what does it all mean?

It can happen: you read the description of a new asset and encounter completely unfamiliar words as recommendations for working with it. For example, the description may contain phrases like ‘not compatible with acrylates, polymers’ or ‘addition of electrolytes may reduce the viscosity of the finished product’. And then there are words like ‘organic solvents’, ‘buffer solutions’, ‘chelators’ and other terms that can scare off a novice creamer.

And in fact, everything is not so complicated and many cosmetic terms once you even heard on the course of school chemistry, let's understand it together.

What are solvents in cosmetics and why are they needed?

In the cosmetic industry, some components are dissolved in other components in order to mix everything properly and get a stable cosmetic formula. Most often, there are either hydrophilic components (i.e. water-soluble) or lipophilic components (i.e. fat-soluble). Therefore, the most common solvents are also water and oils (or emollients). Pre-dissolution of the components in the recommended medium promotes its more uniform distribution and prevents, for example, precipitation or greasy droplets on the surface of the aqueous product. But sometimes in the technical documentation of the raw materials we may come across such a phrase as ‘dissolved in organic solvents’, but which components are meant by the phrase ‘organic solvents’?

Organic solvents

Organic solvents are mostly liquid volatile chemicals of organic origin with a characteristic odour, which are able to dissolve a variety of components and materials. This is a rather large group of substances that are effective against a considerable list of solid compounds: both low molecular weight and polymers (resins, paints, varnishes, rubber, rubber, plastics). They dissolve, promote extraction, degrease, rinse, etc. Organic solvents (OR) have different classifications, depending on what underlies the division: chemical structure, physical characteristics or other indicators.

Most commonly, organic solvents are distinguished by their chemical origin:

• alcohols;
• ketones;
• esters (simple and complex);
• hydrocarbons;
• halogen-containing;
• others.

In cosmetics, ORs from the alcohols category are commonly used. This includes the most popular component glycerin (yes, yes, it is a three-atom alcohol). Various glycols (alcohols that contain two hydroxyl groups -OH): pentylene glycol, propylene glycol and its plant analogue propanediol. And of course simple alcohols such as isopropyl alcohol and ethyl alcohol.

If glycerin and glycols are actively found in the composition of cosmetic products, as in addition to the properties of solvents they act as moisturisers, softeners, conductors of assets, then the usual alcohol all try to bypass, because of its likely harmful effects. But is it really harmful? Let's get to the bottom of it.

Of course, alcohol dries the skin, but it is this property that comes in handy in products for oily skin types (in addition, alcohol dissolves salicylic acid). As shown by in vitro studies (on isolated cells), alcohol can cause cell death or activate inflammatory processes, but with direct and prolonged exposure. In real life, however, alcohol needs to overcome the dense stratum corneum, which is extremely difficult, additionally considering the rapid evaporation of alcohol from the skin during application.

Therefore, with proper dosage and prescription of alcohol-containing products, their harmful effects are extremely low.

Solubilisers in natural cosmetics formulas

And what to do if it is necessary to dissolve a fat-soluble active in an aqueous medium. This is where a number of other cosmetic solvents, or in other words solubilisers, come to our aid. We have discussed what a solubiliser is in detail in a separate article (read here), but now we will just share a list of popular solubilisers:

• PEG-40 (hydrogenated castor oil)
• polysorbate-20 and polysorbate-80
• water-soluble oils
• pentylene glycol
• Resassol VPF.

It is with the help of these magic ingredients that you will be able to dissolve the fat-soluble components and further add them to water.

Polymers and copolymers in cosmetics

Polymers make up the second largest class of ingredients in cosmetics and personal care products. In terms of chemistry, polymers are high molecular weight molecules composed of many repeating segments (monomers), usually arranged as a chain.

Copolymers are a type of polymers that are characterised by the fact that their macromolecules are composed of different structural links.

Indeed, polymers are found in hair products such as shampoos, conditioners, hair repair products, hair dyes, moisturising masks, fixative gels; in skin care products such as liquid soaps, moisturising lotions, sunscreens; and products used for nail care, make-up and perfumes

Each of these products has different functions and applications, which accounts for the diversity of action of polymers. Therefore, their structural diversity is used in cosmetic formulations to perform different functions: as rheology modifiers, thickeners, foam stabilisers and destabilisers, emulsifiers, fixatives, conditioners and film formers.

Polymers are classified as follows:

• Synthetic: silicone, polyester, polyamide, poloxamer, polyacrylate, polyethylene glycol, etc;
• semi-synthetic: cellulose acetate, cellulose nitrate, other cellulose derivatives;
• natural: polysaccharides, xanthan gum, alginate acid, chitosan, cellulose, collagen, silk, hyaluronic acid.

Let's look at some popular polymers in a little more detail.

Polyacrylates

Polyacrylates are most often water-soluble polymers that are derivatives of carboxylic acids. They are used as thickeners in cosmetics, as acrylates form viscous, transparent and non-sticky gels. They are also able to reduce the stickiness of components such as, for example, glycerin. However, it should be realised that polyacrylates themselves are not fast degradable products. Therefore, if you produce natural biodegradable cosmetics - it is better to use vegetable gel formers with a high degree of degradability, for example, xanthan gum.

Also, when working with acrylates it is important to take into account that there are assets that are incompatible with them, for example, in the case of adding salts of pyrrolidonic acid (PCA), usually it is zinc or copper PCA, with which the viscosity of gels on polyacrylates sharply decreases.

Cellulose and its derivatives

Cellulose is one of the widely used natural polymers. However, cellulose itself is insoluble in water and therefore cannot be used for cosmetic purposes in its natural form. It needs chemical modifications such as, for example, substitution reactions. When chemically modified, cellulose fibrils create products that are non-irritating to the skin, with good spreading and sensoriality to the skin.

Anionic modified cellulose polymers are used as thickeners to increase the viscosity and stability of cosmetic formulas. And for example, a cationic hydroxyethyl cellulose polymer called polyquaternium-10 is widely used in hair care products as it has anti-static and moisturising properties and makes hair smooth and shiny.

Cellulose is also famous for the fact that it can be combined with other natural polymers for cosmetic applications.

What are electrolytes and why they are in cosmetics

Electrolytes are mineral compounds that can conduct electricity. They are usually found in the blood and tissues in the form of salt solutions. Such components are able to move nutrients and moisture into the cell and remove metabolic waste products from the cells. Electrolytes have become one of the new trends in the cosmetic industry in recent years.

Electrolytes in cosmetics are often used as moisturisers to help balance the skin's moisture levels and provide essential nutrients. Electrolytes can also help regulate skin pH and reduce inflammation. In addition to their moisturising properties, they also have antibacterial and anti-inflammatory properties. This makes them interesting for anti-pollution skin care, as they can help protect the skin from dirt particles in the air.

The most common electrolytes in cosmetics are calcium, potassium, sodium and magnesium salts. And of course, you've heard of a component like calcium lactate! It's what makes alginate masks the way we all love them, and it's also an electrolyte. Magnesium sulphate, that English salt or magnesia that is so wonderful for relaxing muscles, yes, that's an electrolyte too. And let's not forget atomised sea water, which is a treasure trove of minerals and is so often included in recipes for toners, toners and serums to hydrate and retain moisture in the skin.

Some of the electrolytes that are common now are MgPCA and NaPCA. These are the magnesium and sodium salts of pyrrolidone carboxylic acid, which form part of the intercellular matrix of our skin. Therefore, these electrolytes have a great influence on our skin's natural moisturising factor. Sodium lactate, the sodium salt of lactic acid, which is produced by our skin to maintain physiological pH and retain moisture, is also commonly used. In addition, the moisturising agent inhibits the growth of microorganisms that are foreign to the skin.

However, when adding electrolytes to cosmetic formulas, we must remember that their presence in the recipe can reduce the viscosity of the finished cosmetics or even break up the formula, so we should always test them. Often in the recommendations for the manufacture of cosmetics we find recommendations for the introduction of electrolytes at the last stage of manufacture, that is, when the emulsion or gel is already ready and stable.

What is a buffer solution

The main task of a buffer solution is to maintain and stabilise the pH of the finished cosmetic. This is very important because many actives (preservatives, surfactants) work only at a certain pH level. The skin also has a certain pH and in order for the cosmetic to not irritate the skin and work, the acid-alkaline balance of the skin and the cream should be close in value.

Usually, a buffer solution is an aqueous mixture of a low concentration of an acid and its salt or an alkali and its salt. For example, you can buy sodium citrate, which is the salt of citric acid, at Beurre. To create a buffer solution based on it, you need to dissolve it in water and add citric acid in certain proportions. We have described more about buffer solutions in a separate article (read it here)

What are chelators and why they are in a cosmetic formula

A chelating agent (chelator) is a substance that can react with metal ions to form chelates - compounds that cannot react with other substances in your product. You may have come across the synonym for these substances more often - chelating agents. Essentially, chelating agents bind metal ions, preventing them from spoiling your cosmetics. Hence the properties of a chelator, which:

stabilise the system as a whole, preventing some assets from precipitating out
prevent the decomposition of components and oxidation of oils
increase the shelf life of the cosmetic product
have additional cosmetic properties (this applies only to natural chelators).
You can read about chelators in cosmetics in our article at the link, and below you will find a list of the most popular chelating agents:

• Dermofeel PA-12 (Sodium Phytate)
• Dermofeel PA-3 (Sodium Phytate solution with alcohol)
• Tetrasodium EDTA
• Sodium Citrate
• Gluconolactone
• and also in the BEURRE shop range there are 2 preservatives with chelating properties, Cosphaderm LEO (thanks to Caprylhydroxamic acid in its composition) and Geogard ultra (thanks to gluconolactone in its composition).

We hope that after this article you have learnt fewer ‘scary’ terms from the cosmetics industry. And now technical texts will become more understandable for you, and the creation of stable and effective products will be much easier.

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