What makes a good moisturizer and do you need a separate day and night moisturizer?
The function of a good moisturizer should be to hydrate the skin and protect the skin barrier function. One of the most important ingredients of a moisturizer is water; only water can hydrate. A moisturizer needs should be a good balance between water to hydrate and oils and other ingredients to help prevent water loss from the skin.
Oils are great for softening skin, preventing water loss from the skin and providing the skin with fatty acids. Vegetable oils are best as they are far more nutrient dense than mineral oil. We use a blend so that there are many different fatty acids. Humectants are also an important ingredient in a moisturizer to help hold water. Good humectants include be glycerin, hyaluronic acid, herb extracts, proteins, sorbitol, or algae extract. There is a wide range of humectants that benefit skin.
A good moisturizer should also contain antioxidants because they can help repair skin damage. There are many antioxidants, but some that we like to use include vitamin C, alpha lipoic acid, green tea, vitamin E, and a variety of herb extracts.
There are no absolute differences between a day cream and a night cream so you really don’t need two different moisturizers for day and night.
An important thing to note though is that a day cream should not contain ingredients that might cause photosensitivity or make the skin more sensitive to sun damage. These include alpha hydroxy acids (glycolic acid, lactic acid, malic acid), and retinoids (retinyl acetate, retinol).
Texture is also a big difference. Night creams tend to contain heavier emollients and be oilier than a day cream. A day cream should be light enough and soak in well enough that you can apply makeup immediately after using. But this also is a matter of preference as well as climate. In a drier climate you may want a heavier cream during the day as well as night. Some day creams will also contain a sunscreen ingredient. If yours does not you may want to consider applying a sunscreen on top of your day cream or wear a hat.
Many companies will formulate a night cream to be more of a repair product containing actives to repair and rejuvenate skin. Skin is always undergoing repair processes though so these ingredients are just as beneficial in a day cream. Colorado Aromatics Springtide Face Cream has humectants, antioxidants and repair ingredients that might be found in a night cream but has a nice light feel for day.