This serum by Kiehl's from their Ultra Facial range is a great product, not only for the colder times of the year. I have been noticing that a lot of my friends are experiencing really dry skin because they are still using products for blemish-prone skin, as this is what they are used to, and it is easy to miss the transition, to when your skin gets better and products targeting blemishes often dry skin out a lot. A serum is a great way to get moisture into the skin, and it is used before using a moisturiser. This product by Kiehl's has a really nice consistency and feels like a smooth layer on the skin. The smell is a little strange to begin with, but you get used it to! The price, 29 Pounds for 50 ml, is quite alright for a serum, as the ingredients are very concentrated. Other fantastic alternatives include the HydraQuench serum by Clarins, which is more expensive, 40 Pounds for 30 ml.
If you are unsure about your skin, it is always great to get your skin analysed. Kiehl's do a quick skin analysis at their counters or in store, as do spas offering skin treatments. They are often free, and offer a great alternative to get your skin checked out so that you can purchase the best products. And do not be alarmed if your skin is very oily, it can also mean that your skin is dehydrated and producing a lot of oil to compensate for this. So get it checked out and then it is much easier to buy the right products targeted at your concerns!