As a carrier oil, you can pretty much choose what you want! Sesame oil or rice bran oil are great oils for a balance of oleic acid and linoleic acid. You can try combining something like soybean oil (high linoleic, very moisturizing) and olive oil (a little thicker but very moisturizing and a great humectant). Or you could use a high linoleic oil combined with high oleic camellia oil to get the benefits of both types of fatty acids for a lighter, drier feeling serum. And squalane is always a welcome addition to a serum if you want something really light and well absorbed. Let's go with squalane, soybean, and camellia oils as our base for this serum.
Also consider using fractionated coconut oil as a base for your serum. It is very light, easy to spread, and offers great moisturization that will sink into your skin. It doesn't have all the fancy polyphenols and fatty acids offered by the other carrier oils, but it does offer fantastic moisturization in a colourless, odourless, very stable oil. (More about this oil in a few days...)
Borage or evening primrose oils, I think, would be essential for a dry skin serum. Both offer great barrier repair features and moisturization, as well as some anti-aging features. (If that's what you want in a serum!) I'm going with evening primrose as is it anti-oxidant in nature, and that's never a bad thing! Let's go with 10% for dry skin and 20% for very dry skin. And let's go with 10% borage oil for barrier repair.
One oil I haven't mentioned yet is sea buckthorn oil (see a blurb here, look for a post in a while on this topic). Sea buckthorn oil contains a ton of tocopherols - 2,470 ppm - which will offer great softening and moisturizing features for dry skin, and it is showing great promise in helping regenerate damaged skin. Consider using this at 10% in your serum.
Two other oils - carrot oil and rosehip oil (again, see blurb until I post!) - are great for dry skin. Rosehip oil can aggravate acne, but it contains high levels of GLA and retinoic acid. Carrot tissue oil is great for very dry skin. Considering using one of these oils in your serum.
FACIAL SERUM FOR DRY SKIN
20% soybean oil
20% camellia oil
10% evening primrose oil (20% for very dry skin, reduce the squalane by 10%)
10% borage oil
10% sea buckthorn oil
10% rosehip, carrot, or other oil that looks nice to you
Yes, I know this looks a lot like the oily skin version, but there are differences. We are going with more ingredients to moisturize and with oils containing a lot of Vitamin E for softening and moisturizing. We're also using a lot of GLA to help with barrier repair, because that can be an issue for people with dry skin, and to decrease the transepidermal water loss.
Feel free to play with a serum you like - heck, post it here so you can share it with others! - because everyone's skin is different. There is no one magic oil that works for everyone awesomely (is that a word?) I love borage and rice bran oil - it might make you break out. But try these things for at least 7 days to see if they work (although if you are irritated, stop!)
Join me tomorrow for fun with coconut oil!