If your skin is as dry as the Serengeti then it might be time to invest in a decent moisturiser. But which type do you go for?
Winter often comes hand-in-hand with grey, and sometimes scaly-looking, skin. The scientific term for this is transepidermal water loss (or TEWL) which refers to the loss of moisture from the skin through evaporation.
Moisturiser is designed to prevent evaporation by trapping moisture in or replenishing it in the epidermal layer - in other words, it's pretty magical stuff (and well worth stocking up on in your beauty cupboard).
A recent video posted by the American Chemical Society for their Reactions series explains that there are three types of moisturiser, all of which can help nourish your skin in different ways.
Occlusives are the old school moisturisers, which work by forming a barrier over your skin that water can't penetrate. This then stops moisture from evaporating out of your skin and traps it in. Vaseline is an occlusive moisturiser.
Emollients are a more popular choice of moisturiser and are designed to penetrate the skin's surface and make the skin softer and more flexible.
According to NHS Choices this particular type of moisturiser is often used to help treat dry or scaly skin conditions such as eczema and psoriasis.
Meanwhile, humectants help to trap and retain moisture in the epidermis, which is the top layer of skin. This type of moisturiser also helps to bring younger, moist cells towards the outer layer of the skin and reduces flakiness.
It also stimulates the body's natural production of ceramides, which reduces TEWL.
So which one do you go for? There is no right or wrong answer - as it's dependent upon the severity of your dry skin. If your skin is flaking - opt for emollients. If you just want to keep it in good condition, then perhaps try an occlusive moisturiser. And if all else fails, try humectants!