Why do we need serums?

When discussing skincare with clients and chums I’m always asked why we need serums and what it is they actually do. Elle Turner from The Pool has just published an almost word for word explanation of what I say! Hope this helps:
“Toners, primers, serums – all operate within the realms of beauty products we know we should use. But they’re actually quite a head-scratcher when it comes to pinning down why we really need them. Serums aren’t quite a moisturiser or a lotion. So, what exactly are they?
Put simply, a serum is a more potent version of your regular skincare, which means that, by volume, they have a much higher concentration of active ingredients. These could be things like vitamin C, hyaluronic acid or retinol. While moisturisers may have these strong ingredients in the mix too, they’re surrounded and diluted by emollients with larger molecules that help to moisturise and create a protective barrier over your skin. Serums tackle “more specific concerns, such as visible lines, intense dehydration and uneven skintone,” says dermatologist Dr Nowell Solish. They’re much more lightweight, with smaller molecules, and therefore more easily able to penetrate down deeper into your skin. “For example, a serum can help stimulate collagen beneath the skin’s surface, rather than sitting on the skin’s surface,” Dr Solish explains. They’re most effective when applied before your moisturiser and, as a general rule, it’s best to apply products from thinnest to thickest.”