Dry vs dehydrated skin: how to tell the difference
Dry skin is short of the oils and fats that hold water in. Dehydrated skin is short of water, and it can happen to any skin, including oily skin. In practice the two overlap, because skin that's low on fats loses water faster. If a richer cream fixes it, think dry. If you feel tight but still shine, think dehydrated.
A caveat before we start. "Dry skin" is a medical term. "Dehydrated", used about skin, is more of a skincare word, so don't take it as a diagnosis. It's still a useful way to think about what your skin needs.
The difference
| Dry | Dehydrated | |
|---|---|---|
| What's low | Oils and fats in the outer layer | Water in the outer layer |
| Who gets it | Often a long-term tendency | Anyone, comes and goes |
| Feels like | Rough, flaky, sometimes itchy | Tight, thirsty, a bit flat |
| Can still shine? | Rarely | Yes |
| Helped most by | Thicker creams, gentler washing | Hydrating products, sealed in |
What's going on with dry skin
DermNet explains dry skin as a problem with the outer skin barrier: there's less of the fats in the outermost layer, so it holds less water. Triggers include low humidity, direct heat, excessive air conditioning, too much bathing, and soap and detergents.
What's going on with dehydrated skin
This is usually about your surroundings or your routine: a windy week, a harsh cleanser, too many strong products, a dry room. Skin feels tight and looks a little flat, but it may still get shiny. That's why people with oily skin often miss it, and why scrubbing away more oil usually doesn't help.
A rough way to tell
- Flakes, rough patches or itch? Lean dry.
- Tight after washing, shiny by lunchtime? Lean dehydrated. Your cleanser might be involved.
- Worse in winter, and on your hands and shins too? Lean dry.
- Came on suddenly after a new product? It may be irritation rather than either. See what to do if a product irritates your skin.
What helps both
DermNet's page on moisturisers describes three kinds of ingredient:
- Humectants such as glycerine and urea attract and hold water in the top layer. Hyaluronic acid works in a similar way.
- Occlusives such as petroleum jelly and dimethicone form a layer that reduces water loss.
- Emollients soften skin by filling cracks in its outermost layer.
For skin that's dehydrated, a light hydrating product under a moisturiser is often enough. For dry skin, go thicker: DermNet says the drier the skin, the thicker the product should be, and that emollients generally work best on damp skin. So moisturise straight after washing, before your skin has dried off.
Keep showers warm rather than hot, and swap soap for a gentler cleanser. Drinking enough water is sensible and DermNet includes it in its advice, but it won't by itself fix tightness from a harsh cleanser.
Where a mask fits
A hydrating mask is a pleasant extra for either one, not a fix. It covers skin for 15 to 20 minutes and holds water against it, and skin feels softer afterwards. Keep that going with a moisturiser straight after. Our page on dry, tight skin has the formulas we'd start with. If your skin mostly feels tight, Hyaluronic Acid is the one we'd try first.
When to see someone
See your GP if your skin cracks, bleeds, itches enough to keep you awake, or doesn't improve after a couple of weeks with a good moisturiser.
Questions
Can oily skin be dehydrated?
Yes. Oil and water are different things, so skin can be shiny and still feel tight. A light, hydrating moisturiser is usually a better idea than stripping away more oil.
Does drinking more water fix dehydrated skin?
It's sensible to stay hydrated, but it won't by itself fix tight skin caused by a harsh cleanser or dry air. Gentle cleansing and moisturiser usually make a bigger difference.
This is general information, not medical advice. If you're worried about your skin, see your GP or a skin specialist.
Sources
- Dry skin, DermNet
- Emollients and moisturisers, DermNet