‘Knowledge is power’: how to decode skincare ingredients

Reading the ingredients list on your moisturiser might induce a migraine, but there are tricks to understanding precisely what you’re putting on your skin

Do you read the ingredients of your skincare products? I love to, but I’m probably in the minority here. I want to share what I know so you can be better equipped to assess whether or not a product will do what it promises to do.

Whether the product contains ingredients known to back up its claims : I’ll often scan the active ingredients when investigating a product. For example, if a product claims to "brighten" skin, I might expect to see vitamin C or niacinamide. If it's for sensitive, compromised skin, I don't like to see lots of fragrant plant oils like lavender or geranium. They’re not bad for everyone with sensitive skin, but they make me itchy.

The approximate amount of a specific ingredient : The dose makes the poison. Some ingredients, such as alcohol, get a bad rap but have their uses. Alcohol is a great penetration enhancer and largely evaporates before it sinks into your skin. It can be drying at high concentrations, so you wouldn't want a hydrating product like a moisturiser to be 50% alcohol but 1%, for example, would be fine to help dissolve another ingredient. Use your common sense and best judgment.

The inclusion of allergens or ingredients you don't like: Check for these, much as you would on an ingredient list for food.

There are guidelines for how ingredients are listed on personal care products.

They must all be named according to the Inci (International Nomenclature of Cosmetic Ingredients), an international standard that ensures ingredients are called the same thing worldwide. For example, the Inci name for green tea is Camellia sinensis leaf extract.

Everything must be listed in order of quantity. If it's first on the ingredient list, it is the most abundant ingredient. However, this is not true for South Korean products.

The top five ingredients make up most of the mixture, so you can sometimes get a feel for the texture of the product with only this information.

Many ingredients are effective at very low concentrations so more does not always mean better. Peptides, for example, are effective at very small concentrations – parts-per-million small!

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Once you get down to 1% or less, ingredients can be listed in any order, so brands will sometimes list the most exciting ingredients first.

Perfumes are exempted from listing full ingredients as they’re considered a trade secret; however, known irritants do need to be listed.

Once you’re across this info, it's about recognising which ingredients do what – and that takes time and practice. Use Inci Decoder to search for products, or copy and paste ingredient lists to get a breakdown of each ingredient.

Preservatives help to prevent growth of bacteria and mould products. Some commonly used safe and effective preservatives include phenoxyethanol, methylparaben, potassium sorbate, benzoic acid, chlorphenesin and caprylhydroxamic acid. Some products use sterile packaging instead of preservatives.

Solvents are ingredients that dissolve other ingredients. Water is a solvent for sugar or salt. Alcohol is another example of a solvent, as well as propylene glycol which is used in many applications for its moisturising action.

Chelating agents react with metal ions and prevent them from reacting with our skin or products, to keep things stable. There are metal ions in water (especially hard water, which makes it challenging for skin and hair) and other skincare ingredients such as iron oxide pigments. Metal ions can sometimes help bacteria grow so chelating agents can make preservatives work better.

Buffers are used to adjust the pH of skincare products. For example, it can ensure a moisturiser is not too acidic.

Surfactants break surface tension. They enable oil and water to mix in order to cleanse oil from skin, create a foam, make lipids and water-soluble ingredients sit nicely in a moisturiser without separating, and help deliver ingredients into your skin. Some are kinder to skin than others.

Emulsifiers are a type of surfactant that helps mix things together that wouldn't otherwise mix. Its job in personal care products is to stabilise the oil and water phases so the product doesn't separate. It's very important that oil and water don't separate, especially in sunscreens, which must form an even film of UV filter to adequately protect skin.

If you’re having issues with a skincare product, note what's on the ingredient list in case you run into the same issue with another product later. Knowledge is power.

This is an edited extract from Your Best Skin by Hannah English, published by Hardie Grant.