What is the purpose of glycerin?

What does glycerin do for your skin?

Glycerin helps increase the water held in the stratum corneum, the skin's outermost layer. That layer needs water to stay smooth and supple and to shed dead cells in an orderly way. When it lacks water, dead cells accumulate, skin becomes flaky, and cracks can develop. Hydration is therefore about how the surface functions, not just how it feels when you touch it.3

Humectants draw water from deeper skin layers and, to a limited extent in humid conditions, from the air. In low humidity, most of that water comes from within the skin. A damaged, dry outer layer can lose the water drawn into it, so humectants are usually combined with occlusive ingredients that hold moisture in. For everyday moisturizing, a formula that attracts water and limits its escape is the practical choice.3

How is glycerin different from oils and petroleum jelly?

A moisturizer can contain all three types, and some ingredients perform more than one role. Glycerin supplies the water attracting part; an occlusive supplies the moisture retaining barrier. The whole moisturizer matters more than a single name on the front, which is a lot of responsibility for one ingredient to carry.13

Which glycerin moisturizer should you choose?

Match the moisturizer to the degree of dryness and the area you are treating. Lotions suit mild dryness and hairy areas, including the scalp. Creams suit moderately dry skin. Ointments provide the strongest occlusive effect and suit very dry, scaly areas, although their greasy feel can make them less appealing. These differences concern the complete formula, not glycerin alone.4

A water containing lotion or cream combines hydration with ingredients that help retain it. Petroleum jelly and moisturizing oils contain no water, so they are best applied while skin is still damp.13

How do you use a glycerin moisturizer?

1. 1Wash gently. For dry skin, use a gentle cleanser rather than regular soap, and avoid scrubbing.
2. 2Keep baths and showers warm rather than hot, and limit them to 5 to 10 minutes. Hot water removes natural oils that help skin retain moisture.
3. 3Pat skin dry rather than rubbing it, leaving the surface damp.
4. 4Apply your glycerin containing moisturizer after bathing to help lock in moisture.
5. 5Reapply during the day as needed. General dry skin care guidance is to moisturize 2 to 3 times daily, or more often when necessary.

There is no special morning or evening window for glycerin moisturizers. Applying immediately after bathing is useful, but other times work too. Slightly dry skin can need only a light moisturizer at night; very dry skin can benefit from a more occlusive product every couple of hours. Those are moisturizer routines based on dryness, not a fixed dose of glycerin.2

What results should you expect?

The useful results of moisturizing are less dryness and better skin integrity and barrier function. Moisturizer benefits are greatest during the first six hours after application, which is why regular reapplication can matter. This is ongoing moisture care rather than a one time fix.2

In a four week trial involving 49 adults with atopic dermatitis, a form of eczema, a glycerol containing cream performed better than a simple paraffin cream on measures of skin barrier function. A cream combining urea and glycerol performed better still. Participants applied the creams twice daily to separate areas of their forearms. The combined cream improved moisturization and reduced the skin's response to a test irritant.6

For eczema, the choice of moisturizer matters beyond whether glycerin appears in the ingredients. Different creams have different effects on the skin barrier. Regular moisturizing is baseline care, with anti inflammatory treatment added when needed. A glycerin moisturizer is therefore part of moisture care, not a reason to replace prescribed eczema treatment.6

What if your skin is sensitive or acne prone?

Assess the complete formula. Moisturizers can cause burning, stinging or contact allergy, and suspected allergy can be investigated with patch testing. Urea and lactic acid preparations often sting on scratched, cracked or inflamed skin. That matters when choosing a moisturizer combining glycerin with those ingredients.4

Highly occlusive emollients can aggravate acne and cause folliculitis, inflammation around hair follicles. For acne prone skin, the fact that a moisturizer contains glycerin is not enough to decide whether its overall texture and formula suit you. Stop using a moisturizer if contact dermatitis develops.2

When should dryness get medical attention?

Contact a healthcare professional if:

• Dryness and itching keep you from sleeping.
• Scratching has caused open cuts or sores.
• You feel itchy without a visible rash.
• Moisturizing and other dry skin care measures do not relieve the dryness and itching.