How Moisturisers Work
Humectants such as glycerin attract and hold water; emollients soften and smooth the spaces between surface cells; occlusives such as petrolatum reduce water loss by forming a barrier. Many effective creams combine all three functions in different proportions.
What matters most.
- Ingredient roles overlap and formulas matter more than isolated names.
- Humectants work best inside a complete moisturising system.
- Occlusives are valuable for water-loss reduction but can feel heavy.
- Ceramides are barrier lipids, not simply another hydration buzzword.
Humectants help hold water
Glycerin, hyaluronic acid and urea are familiar humectants. They help attract water into the outer skin layer or retain it there. This can improve flexibility and reduce a tight feel.
A humectant headline does not tell you the concentration, supporting ingredients or finish. In very dry conditions, a formula also needs enough emollient or occlusive support to limit evaporation.
- Glycerin
- Hyaluronic acid
- Urea
- Lactic acid
- Sodium PCA
Emollients make a rough surface feel smoother
Emollients fill spaces around flaking surface cells and improve softness and slip. Fatty alcohols, plant butters, squalane and many oils can play this role, although every formula balances feel and stability differently.
Emollient does not mean non-allergenic. Lanolin, botanicals and other ingredients may be excellent for one person and unsuitable for another. Personal tolerance remains part of the decision.
Occlusives slow water from escaping
Petrolatum, mineral oil, dimethicone and waxes can reduce transepidermal water loss. Petrolatum ointment is a clear example of a highly occlusive format; creams usually provide a lighter balance.
Occlusion can be especially useful over small rough areas or overnight. It can also feel greasy, trap heat or be impractical under clothing. Use the amount and location that solve the problem.
- Petrolatum
- Mineral oil
- Dimethicone
- Waxes
- Some plant butters and oils
Choose the formula, not a single ingredient
For broad everyday dryness, look for a moisturiser that feels comfortable and combines hydration with surface smoothing and water-loss reduction. Ceramides or other barrier lipids can add another useful dimension, especially when the formula is designed around barrier support.
For rough thickened skin, urea or lactic acid may provide both hydration and targeted smoothing, but they can sting cracked or inflamed areas. For sensitive skin, fragrance-free positioning and a manageable ingredient list can make troubleshooting easier.
Common questions,
clearly answered.
Is hyaluronic acid enough for dry skin?+
It can contribute hydration, but many dry-skin routines benefit from a formula that also contains emollient and occlusive components to smooth skin and reduce water loss.
Are ceramides humectants?+
No. Ceramides are lipids naturally found in the skin barrier. In moisturisers, they are used as part of a barrier-support strategy.
Is petrolatum bad for pores?+
Petrolatum is highly occlusive and can feel heavy. Whether it suits an acne-prone area depends on the whole product and individual response; a targeted use may be more practical than full-face application.
How this guide was prepared
Our editorial team used the following authoritative health and dermatology resources. This guide provides general information and does not diagnose or replace personalised medical care.
Published 22 January 2025. Last updated 21 July 2026. We revisit guides when source guidance or relevant product information changes.