impaired skin barrier and it probably has lower hydration levels - and we should be able to figure out which ingredients could benefit this skin type so you can make awesome products!
We want to formulate our products with occlusives, humectants, and emollients. Wow, that couldn't get more general, eh? We formulate every lotion with these three components, so let's take a look at which occlusives, humectants, and emollients offer maximum benefits for dry skin. You can choose from a number of different ingredients in of each of these categories, and for the most part, it's about your personal preference, your supplier's stock, and the ingredient's affordability!
There are three approved occlusives - dimethicone, cocoa butter, and allantoin - and you could use one of each of all in a product. For instance, I might use 2% dimethicone (cool down phase), 0.5% allantoin (heated water phase), and 5% cocoa butter (heated oil phase) in a hand lotion. (If you want to stay more "all natural", don't use the dimethicone.)
There is some debate about using allantoin in the heated water phase versus the cool down phase. I use my allantoin in the heated water phase to increase its solubility and ensure it doesn't leave little shards behind. Some people like to use it in the cool down phase to avoid the shards. I found cool down phase equalled shards for me, so I prefer the heated phase, but either phase works.
And there are other occlusive ingredients that might work well. I like to add 2% beeswax to a hand lotion to make it more tenacious after hand washing. I enjoy adding more butters to body lotions to make them thicker - shea butter for a slightly greasier feel, mango butter for a slightly drier feel - which will increase their occlusive nature. Cetearyl alcohol will make your product feel thicker and waxier than cetyl alcohol, and stearic acid will make your product feel thicker and more tenacious than cetyl alcohol.
I'd definitely choose a high linoleic acid oil as my main emollient - sunflower, soybean, sesame, or rice bran, or wheat germ oils - but these can feel a bit greasy on your skin. (I don't want to suggest grapeseed oil or hempseed oil as they have very short shelf lives - 3 months - but they are also high in linoleic acid.) Vitamin E is very good for dry skin, so my suggestions would be wheat germ or soybean oil as my first choices for dry skin, but these are both greasier feeling oils than sesame and rice bran, for instance.
You could choose a high gamma-linoleic acid oil, like evening primrose or borage oil to help with dry skin, or consider using cranberry oil or rosehip oil, although the latter is known to aggravate acne. These exotic oils will feel less greasy than the carrier oils (for various reasons), but they are definitely more expensive!
If you don't like a greasy feeling lotion - and I really encourage you to try making one before you decide that you don't like greasy feeling products because homecrafted lotions are almost always less greasy than store bought ones - consider adding 2% IPM or IPP to your product to reduce that feeling.
You could also consider using an oil with conjugated linoleic acid (or CLA) as it shows signs of helping with dry skin. Calendula oil would be your choice here, and it's filled with Vitamin E. It's quite pricy, so I'd encourage you to make sure you aren't using this as the only oil in a product.
aloe vera! Polysaccharides are hydrating, emollient, anti-inflammatory, and create a barrier on our skin, thanks to the wonders of gelling.
I'll go into more detail about extracts and other things we could add to our products tomorrow!
We've just spent a week covering humectants (and I'd really encourage you to read those posts rather than having me discuss them again here), and I think it's safe to say that the science shows that regardless of humidity, humectants are your friend! I would suggest that you consider loading up on humectants in any product for dry skin, not just lotions, but cleansers, body washes, and so on. When I choose to make lotions for dry skin or for winter, I always include at least two humectants and possibly three. For instance, I'd use 3% glycerin and 2% sodium lactate or sodium PCA in the heated water phase and 2% panthenol in the cool down phase.
There are tons of options and combinations of these ingredients you could use for dry skin, and those of you with dry skin no doubt have opinions on these ingredients, so let's take a look at extracts and other things we could add for dry skin tomorrow, then we'll formulate a few lotions for dry skin starting on Monday!
Emollients: Oils, butters & esters
Formulating for dry skin: What is dry skin?
Formulating for dry skin: Impaired skin barrier
Formulating for dry skin: Lower hydration levels
Men's products: Formulating a drier feeling, light lotion
Men's products: Formulating a drier feeling lotion