8am.
The morning is an important time for your skin. As you slowly drift into consciousness after a long night of beauty sleep (or are thrust rudely back into the world by your alarm clock) your skin too is moving from one set of activities to another. In other words, it is recovering from a night of regeneration and repair, ready for a day of strength and protection.
Some people find that their face looks blotchy and puffy when they first wake up, but settles down after a few minutes. We will see later exactly what has been happening in the dermal layers while you were alseep, but for the moment, we will consider a morning care routine to maximise your skin's start to the day.
During daylight hours your skin must operate as a protective mantle for the entire body, so its natural functions are geared towards keeping external influences out. In the morning you need to help it prepare for this essential task by cleansing it of all cellular debris from the night's activites. Skin cell turnover is at its most frenetic at night, and surface epidermal cells have been shed as part of this natural process. If they hang about on the stratum corneum they will make your complexion appear dull and sluggish, so an effective cleanser that will rinse them away is a morning must.
Many people prefer to use a foaming cleanser in the morning, but if your skin is very dry, or you simply prefer a cream-based wipe-off formula, be sure that every last trace is removed before you commence the next step in your care routine.
After cleansing, and before emerging into the harsh outside world, you need to apply an effective moisturiser.
Formulas for use during the day are likely to include moisturising and hydrating ingredients, as well as vitamins and other topical nutrients. There are as many variations as there are brands on the shelf, but all will strive to help the skin face up to the rigours of its environment. However, when choosing a moisturising formula for use during the day, always ensure that it contains a UVA/UVB sunscreen, even in winter.

12 noon
By midday your skin is well into its daily routine. The process of cell turnover continues but at a much slower rate than at night. This allows the surface of the epidermis to act as an effective barrier, and maximises the longevity of the acid mantle (the skin's surlace film that helps protect the stratum corneum and repel unwanted bacteria).
The single most influential factor in the long-term appearance and health of your skin is its exposure to UV light, which is at its most intense between the hours of 11am and 2pm. We all know how important sun protection is during the summer months, and when exposed to harsher UV rays on holiday. However, your skin is constantly exposed to ambient light:
ordinary daylight that reaches earth even on relatively dull days here in the UK. Ambient light includes both UVA and UVB rays, although it is only UVB rays that vary in intensity with the strength of the sun.
Harsh UVB rays stimulate melanocytes to release melanin: 'granules' of darker pigment that are placed neatly over the DNA nucleus of every skin cell to prevent UV rays from damaging them at a chemical level. If sun exposure exceeds the skin's natural capacity for protection, and topical sunscreen is not applied, UV rays will cause severe degradation of the skin's fibres. What's more, the crucial Langerhans cells: the skin's defence mechanism against such aggressors, are sensitive to sunlight and desert the epidermis when they feel it under attack.
Meanwhile, UVA rays are present at a consistent rate and intensity all year round. They are silent, and insidious, with the symptoms of exposure only evident years down the line, in the form of sags, bags, fine lines and wrinklies. This is why daily moisturiser with broadspectrum sunscreen is such an important part of your skin care ward robe.

3 pm
By late afternoon your skin has passed its most vulnerable point in terms of UV exposure, but there is still much you can do to maximise its continued performance for the rest of the day. Bear in mind that it is eight hours since you last cleansed and moisturised your skin, and that there has been much water under the epidermal bridge since then. Old make-up, dead epidermal cells and residual sebum, not to mention dirt, grime and pollution, are all lingering on your long-suffering stratum corneum.
If you have a window in your day between 3pm and 5pm, try to reserve a little of it for your skin. If you happen to be on the move at this time of day, invest in high- convenience cleansing formulas, such as facial cleansing wipes, or a rinse-less cleansing mousse. Otherwise a refreshing lotion cleanser should be enough to whisk away unwanted debris. After this, a re-application of moisturiser will help see your skin through to the evening.

9 pm
Your skin will start its nocturnal 'winding down' mid- evening. Once the threat of UV damage has receded, your epidermis will begin to prepare for the night ahead, when It will regenerate and repair itself after a hard day of exposure. This is the time to nourish your skin, and give it the best possible chance to renew its vigour and vitality, not to mention stock it with vital hydrating ingredients and nutrients that will maximise its natural functions at this crucial time. It is an especially good time to indulge in face masks and other deep treats. You should also seriously consider supporting your daily skin care routine with a suitable night cream.
Night cream is fundamental to a good skin care routine. Look for formulas rich in moisturising lipids and nutrients such as vitamins, minerals and ingredients that promote the formation of collagen and elastin. Certain ingredients are best employed at night. For instance, most retinol formulas are developed specifically for nocturnal use, as this anti-ageing vitamin-A derivative is notoriously unstable in daylight. While some manufacturers have found ways to maintain its active life within a daily formula, other sources maintain that this ingredient is best utilised by the skin at night anyway, when its attention turns to regeneration of the very skin cells that have the most effect on the skin's age-related appearance. Other ingredients help support the skin's natural repair function. For instance, vitamin E is considered particularly beneficial when it comes to repairing age spots and other hyperpigmentation problems.

2 am
This is when you are sleeping most deeply and when your skin is most actively repairing and regenerating itself. Skin cell turnover speeds up in comparison to its daytime rate, while circulation to the dermis is increased to support this epidermal activity. Many night creams are formulated to help maximise this part of the skin's natural regeneration process, by delivering vital nourishment and moisture to the skin cells as they are formed. This stocks them with all the necessary vitality to see them through their month-long journey to the stratum corneum. The Langerhans cells, which are active during the day, tend to be particularly energetic at night, when they move between the skin cells looking for bacteria, microbes and otherwise abnormal cells. They bind to and expel any unwanted epidermal lurkers and act as the skin's paramedics, rushing to the site of any injury where they set about healing it. This is why cuts, grazes and spots register the greatest improvement overnight.
Some anti-ageing ingredients are also thought to be best utilised at night. For example, alpha-hydroxy acids loosen dead surface cells ready to be rinsed away with your cleanser in the morning.