Moisturizer ingredients typically include humectants, emollients, fragrances and preservatives. Emollients, such as mineral oil, lanolin, or petrolatum may sink in between skin cells, making the skin appear plumper and smoother. Humectants, such as glycerin or alpha hydroxy acids, generally pull moisture from the air and hold it close to the skin to keep skin moist. Fragrances are usually used in moisturizers to give them a nice aroma, and preservatives typically prevent the growth of bacteria in the moisturizer. Different people might need different types of moisturizers, so the best moisturizer ingredients might vary from person to person.
For those with very dry, cracked skin, oil-based emollients are often the best ingredients. Emollients, such as mineral oil, paraffin, lanolin, or petrolatum, form a protective layer over the skin. This layer holds moisture in the skin in the face of the elements. Oil-based emollient ingredients often leave a residue on the skin. They typically last longer than water-based humectant ingredients, and are generally considered more effective.
For those with oily skin, lighter, water-based humectants, such as glycerin, urea and sorbitol, hold moisture close to the skin without leaving an oily residue that could contribute to clogged pores and acne. Other humectants include sodium hyaluronate, alpha hydroxy acids, and propylene glycol. Water-based humectants are believed to help restore lipids to the skin, to make rough, dry skin appear smoother and feel softer.
For normal skin, a water-based humectant or water-based emollient moisturizer is usually appropriate. Appropriate moisturizer ingredients for normal skin include cetyl alcohol. Ingredients made from silicone are also considered appropriate for moisturizing normal skin.
For mature skin, a moisturizer that combines emollient and humectant ingredients is generally considered preferable. Skin produces fewer natural oils as it ages. Oil-based emollients such as petrolatum or lanolin are generally believed to be good for mature skin. Water-based humectants, such as alpha hydroxy acids, can help to reduce the appearance of wrinkles in mature skin.
Fragrances are often used as moisturizer ingredients. Fragrances can hide the odor of the other ingredients used in the moisturizer and give the moisturizer a pleasant aroma. Fragrances are often responsible for irritating sensitive skin and causing contact dermatitis reactions. Fragrance ingredients such as isoeugenol, hydroxycitronellal, amyl cinnamic aldehyde, and eugenol may be best avoided by those with sensitive skin.
Preservatives are usually used to keep bacteria from proliferating in the moisturizer once the seal has been broken. Preservatives are considered essential moisturizer ingredients, because they help to keep the moisturizer free of bacterial contaminants.