How do beauty products work?

Most of us apply our lotions and potions without giving much thought to how they work. But do we really need everything we use? Here's how some of the products we use everyday work, plus some of the cleverest multi-tasking buys to help save you time and money.

Moisturisers

Designed to help improve hydration in the surface layers of the skin, many contain hyaluronic acid, which is found naturally in the skin and helps it retain moisture. As well as attracting water to the skin, this ingredient helps lock it in, preventing skin from dehydrating.

‘There are many different types of moisturiser, offering different levels of hydration and other benefits, such as UV protection,' explains Chris Flower of the Cosmetic Toiletry & Perfumery Association (CTPA).

Smart buy: Olay Definity Colour Enhancer, £29.99 for 50ml, www.boots.com

New on the shelves this month, this hydrating foundation has a unique moisturiser-serum formulation. As well as providing sheer coverage and SPF15, it helps smooth the appearance of fine lines, wrinkles and brown spots. Results are both instant and long-lasting with long-term, regular use - thanks to anti-ageing ingredients such as niacinamide.

Cleansers

We all know that oil and water don't mix, but that happens to be the reason why washing your face with water alone won't give you a thorough cleanse. A lot of dirt on the skin is oil-based, so you need ingredients that will dissolve these oils. Those ingredients are known as surfactants. ‘There's a broad range of these available, as they are used in many different types of products,' explains Chris. ‘In facial cleansing products, the surfactants used are mild and gentle on the skin.'

Toners

Toners can be used after cleansing to ensure all traces of cleanser are swept away.

Their astringent - or tightening - ingredients also leave skin firmer, and minimise pores. Some also come with extra skincare benefits such as blemish-busting.

Smart buy: No7 Quick Thinking 4-In-1 Wipes, £6.50 for 30, www.boots.com

Cleanse, tone, remove eye make-up and moisturise in one go. Hypoallergenic and fragrance-free, these contain witch hazel, fennel and vitamin B5 - and even work on waterproof make-up.

Instant wrinkle fillers

Most contain hyaluronic acid, which gives a temporary plumping effect. Many also have ingredients such as silicone that sit in wrinkles, smoothing and softening them. ‘Wrinkle plumpers and fillers usually also contain anti-ageing ingredients that stimulate collagen production, resulting in the skin's surface becoming more even over time,' says Nathalie Issachar, head of RoC R&D.

Smart buy: Roc Retin-Ox Wrinkle Filler, £29.95 for 30ml, www.rocskincare.com

With anti-wrinkle retinol and hyaluronic acid, it provides instant plumping plus long-term line smoothing. Use it day and/or night as your regular moisturiser for best results.

Shampoos

Like skin cleansers, shampoos contain surfactants. ‘They latch onto dirt, oil and unwanted residues so they're easily rinsed away,' explains Frauke Neuser, principal scientist, Pantene Pro-V.

Conditioners

‘Conditioners work mainly by wrapping hair in a very thin veil of caring ingredients,' says Frauke. ‘They lock in moisture, smooth the hair's surface and increase shine and softness.'

2-in-1 shampoos and conditioners

Tiny sealed balls of conditioner are suspended in the shampoo. They're so small you can't see them, but when you're rinsing your hair these little balls break open, releasing the conditioner.

‘If you don't rinse properly, you won't get the full conditioning effects,' explains Beverly C, brand ambassador for Goldwell.

Smart buy: Head & Shoulders Classic Clean 2in1 Shampoo & Conditioner, £1.89

Gives you clean, shiny hair in one easy step while protecting you from dandruff.

Can you use face cream on your eyes, or body wash on your hair? Find out here in our 'Do I need it? feature

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