As information is more readily available and there are more affordable skin care options to choose from, I’m noticing more people coming into clinic with compromised skin as a result of over or mis use of topical exfoliating acids.  In search of that extra glow, people are using skin acids too often, in the wrong combinations or on the wrong skin type and wondering why their skin feels dry, red and sore. 
In addition to this they're often not replacing important lipids such as ceramides to help maintain a healthy skin barrier.  So what can they do about it?
 
Well the first thing I do is educate patients about the science behind their skin care routine, in particular use of acids and other products that might sensitise their skin and why. Understanding the skin’s structure is key to understanding how and why to use most skincare products.
The skin has three main layers each with its own specialised function. The top most, epidermis, acts as a barrier preventing loss of fluid and electrolytes as well as offering protection against external insult or injury.  It is this layer that most non prescription skin products work, including mild, shop bought skin acids. It is made up largely of cells called keratinocytes. These tightly packed cells are key in forming a physical and biological barrier to the outside world, regulating temperature and moisture as well as keeping out germs and pollutants.  At a microscopic level, the epidermis on the face has 4 main layers. Keratinocytes start their life cycle in the bottom most layer (stratum basale) and they migrate towards the surface changing as they go until they reach the outermost layer, the stratum corneum.  This cycle takes about 28 days in youthful skin.  By the time the keratinocytes reach this outermost level, they are ‘dead’ or ‘enucleated’ and we call these corneocytes. These are what slough off every day as microscopic flakes to reveal newer cells underneath. As we get older this cycle slows down and as a result the skin can appear thicker, dull and less smooth. It is this layer that skin acids such as glycolic acid are trying to break down to reveal a smoother, more glowing surface.
Corneocytes are glued together by a matrix of different fats to form a waterproof barrier, commonly known as the “brick-mortar” structure, (corneocytes as the brick and lipid interface as the mortar). The lipid interface is made up of free fatty acids, cholesterol and ceramides which are present in the skin in specific ratios. It is this lipid matrix that is key in the ‘barrier function’ of the skin and is often what is stripped away with acid and retinol over use.  In many dry and sensitive medical skin conditions such as eczema part of the problem seems to be an impaired barrier function and lipids such as ceramides are innately deficient in the skin.  As a result replacement of ceramides plays a key role in treatment of these skin conditions. Similarly by over-using strong acids and retinols results in an impairment of the skin’s barrier by stripping its ceramides, resulting in sore sensitive skin.  By reducing or stopping these stripping agents, including harsh alcohol, soap or aha based cleansers, in combination with using ceramide rich products to help to replenish the skin’s barrier function. 

 
What are ceramides exactly and why are they important in skincare?
There are nine types of ceramides in the skin's stratum corneum and they account for 40 to 50% of the lipids in this outermost layer. Without the correct ratio of ceramides, the skin's barrier can become compromised, leading to dryness, itching and irritation. Ceramides also decline with age, contributing to the thinner, drier skin and fine line formation that we associate with aged skin.  Ceramides in skincare work to replace depleted lipids in dry, sensitive or aged skin. Ceramides in skincare are not all created equal and can be expensive if you're not careful, so choosing the right product is important when replacing these important lipids. Ceramides in skincare can be synthetic or natural.  Natural ceramides are mostly extracted from sweet potatoes, whole-grains and brown rice.  Natural ceramides are unstable and are hard to stablise long enough to get to where they need to in the skin and so many skincare brands use synthetic ceramides. Synthetic ceramides traditionally are larger molecules are so can often to be too big to absorb into the skin properly.
 
Japanese ceramide rich range, Curél, is my go-to recommendation for ceramide replenishment for various reasons.
Importantly Curél’s scent free, ceramide like technology has been created so that the molecule is stable and small enough to absorb properly into the epidermis. 
Their whole range is based on not only replacing ceramides but also their face washes act to minimise any disruption to existing, innate lipids in the skin, unlike many cleansers which often strip the skin of these protective molecules. I especially like their Double Cleansing system as it's thorough at getting rid of stubborn makeup, sweat and oil while still maintaining the barrier function of the skin, a balance that many brands haven't managed to overcome.
Curél also have a unique routine for moisturising, known as Double Moisturising.  By applying their lotion (more like a non stripping toner in consistency), there is a lipid gradient for the ceramide rich moisturisers to diffuse down and absorb into the skin when applied.  Both Curél’s Intensive Moisture Facial Cream and Moisture Facial Milk are rich in their ceramide like formula and work to restore the barrier function in both dry, older skin (the former, heavier intensive cream) as well as blemish prone, oilier skin by using the lighter, oil free milk formula. 
Their multi step skincare routine is not only like a luxury ritual (at a high street price) but it suits many skin types and is a brilliant way to help restore your skin barrier if you’ve been overdoing it with acids and retinols, particularly in this dry weather.
 
The whole range is available from Boots and Boots online.