I classify my lotions into four types: Creams or body butters have about 60% water, hand or body lotions have about 70% water, light lotions are about 80% water, and sprayable products or body milks have about 90% water. (Facial moisturizers fall into the 80% to 90% water range depending upon the skin type.) I'll choose one of these basic recipes as my starting point for formulating the type of lotion I want today.
Once you've chosen your type of lotion, consider the skin feel of the product to help you choose your ingredients.
For something like a facial moisturizer, I want something that is non-greasy, something that doesn't feel greasy going on and doesn't leave a shine on my face, and I want something glidy that I don't have to rub in very much.
For a foot cream, I want to use the 60% water recipe and include occlusive and humectants galore. I'm not worried about the greasiness factor as I'm going to be wearing socks afterwards, and I want some really moisturizing ingredients to help with really dry skin.
For a hand lotion, I want to use my 70% water recipe and create a drier feeling lotion with lots of glide that I don't have to work to rub into my skin, but I want something occlusive to reduce transepidermal water loss and to prevent the outside world from making my hands feel drier or more chapped.
These are my preferences, so part of learning to formulate is to figure out what you like and how to make it!
Then consider if you have any other goals - for instance, a lotion for really dry skin, a lotion to prevent weather chapping, a lotion to help with itchiness - and think about which ingredients you can include for that purpose.
If I wanted to create a barrier cream for the winter months, I'd immediately turn to the three approved barrier ingredients - cocoa butter, dimethicone, and allantoin. If I wanted to make a less greasy product, cocoa butter probably isn't my first choice as it can feel greasy, so I'd consider dimethicone and allantoin next. Dimethicone can make a lotion feel a bit greasier, so if I want to use this, I'd choose my oils wisely. If I definitely don't want shine or extra greasiness in a product, then allantoin at 0.5% in the heated water phase would be my best choice.
If I wanted to create a lotion for really dry skin, I know humectants are a big part of formulating for this skin type, so I'll want to load up on things like glycerin or sodium lactate, and I'll want to include some other moisturizers like silk protein, Phytokeratin, panthenol, and cationic polymers. I'll want to choose oils that reduce transepidermal water loss and increase my occlusive ingredients.
If I wanted to create a lotion for camping and summer fun, I'll want something light and non-greasy (I don't want pine needles all over my body!). I'll want to reduce the ingredients that could make me sun sensitive - sodium lactate or sodium PCA at over 3%, for instance, or citrus based essential oils - and I'll want to increase my moisturizing through non-oil ingredients. So I'll want my humectants and film formers to increase moisturization without using more oils or butters. I might even consider using a sprayable lotion to reduce the amount of rubbing in I might have to do.
So ask yourself these questions when you're planning to make a lotion-y type product...
- What kind of product do I want to make? Is it a moisturizer, body milk, lotion, cream, or butter?
- For which body part is this intended? If you're making facial products, you might want to consider the comedogenicity of the ingredients.
- What kind of skin feel do I want? Do I want something light, heavy, dry, or greasy?
- Do I have a specific outcome in mind - for instance, treating really dry skin or preventing further damage by weather - and if so, which ingredients will help with that (both water and oil based)?
- Am I considering this for a specific skin type?