It’s important to know the difference between dry and dehydrated skin

AS IT TURNS OUT, THESE ARE NOT SYNONYMS. AND YOU CAN SLATHER ON AS MANY OILS AND CREAMS AS YOU WANT BUT IT WON’T HELP IF YOUR SKIN IS ACTUALLY CRYING OUT FOR WATER.

❛ Dry’ and ‘dehydrated’ are often used interchangeably, but there’s actually a big difference between the two, says New York dermatologist and cosmetics expert Shereene Idriss. Let’s back up a bit. In her YouTube tutorial on the subject, Idriss lays out the basics. ‘First things first. There is a very big difference between skin type and skin condition. Your skin type is what you are inherently predisposed to, what your genetics dictate. What you were kind of predestined to have when you were born. A condition can appear later on in life, and given your skin type, you can react and respond differently.’

The main difference between dry and dehydrated skin is that dry skin lacks oil, whereas dehydrated skin lacks water. Your skin type is defined by the amount of oil or sebum that your skin produces, so if it underproduces oil, it will be defined as dry.

‘Dry skin lacks oil because it produces less sebum than normal skin, and the lack of sebum means the skin is without the lipids it needs to retain moisture and to build a strong barrier to protect

against external aggressors,’ says skincare mogul Tata Harper. ‘Dehydrated skin does not have enough water. Dehydration is caused by many external factors, but the most common are weather, environment, diet and caffeine consumption.’

Sun damage, lack of sleep and stress can also cause dehydration in the skin. As can a hangover – hence that grey tinge you wake up with after one too many the night before.

Sebum is what locks moisture in. ‘Sebum is produced by the sebaceous glands in your skin,’ Idriss says.

‘It is your body’s natural oil that is being produced to protect your skin barrier from the harsh realities of life. Sebum itself is composed of triglycerides and fatty acids (50– 55%), wax esters (25%), squalene (12%) and cholesterol (4–5%).’

Dry skin often feels itchy and tight. It can crack easily, sometimes it flakes, and it often doesn’t absorb products very easily. Dry skin also tends to have smaller pores – which seems like a benefit, but actually that’s just due to the lack of oil.

Dehydrated skin, on the other hand, generally looks a bit blah. ‘Dehydrated skin may look dull and lack radiance, and may appear ashy if you have a darker skin tone,’ says dermatologist Joshua Zeichner. Fine lines around the eyes can also be a sign of dehydration, but then again your skin could also react by becoming oily or inflamed: think itchiness or breakouts.

This is why dehydration can be hard to spot. Your skin can be dehydrated but still oily. And on the flipside, dry skin can also be dehydrated, since the lack of oil can cause moisture loss.

Confused? So are we, to be honest. But Idriss mentioned something else in her tutorial that may help you pinpoint the problem: ‘You want to treat your skin condition with a serum [see page 122]. That is where the powerhouse ingredients comeintoplay–inyourserum. This is where you are treating your conditions, like pigmentation or dehydration. Moisturisers, on the other hand, target your skin type. They are the ones that are supposed to help complement the type of skin you have, to give it the cushion and the boost that your skin needs.’