Dry or dehydrated? Find out in 60 seconds
Tight, uncomfortable skin is one feeling with two possible causes sitting underneath it, and they don't respond to the same product. That's why the rich cream you keep reaching for sometimes changes nothing at all. Before you buy anything else, spend a minute working out which shortage you have.
Two different shortages
Dry skin is a type. Your oil glands run quieter than average, so there's less sebum on the surface and less of your own lipid slowing water down as it leaves. That's your baseline, the way your skin behaves most of the year, and it usually announces itself right after you wash.
Dehydration is a condition, and it's about water rather than oil. It arrives with a season, a new cleanser, a fortnight of central heating, and it leaves again. Any type can be dehydrated, including oily skin. Plenty of people are greasy and parched at the same time, which sounds impossible and is completely ordinary.
The check
The timing and the shine you answer partly from memory, so evening, at the end of an ordinary day, is the better moment to run this. The squeeze and the surface you read at the mirror on the spot.
Set the mirror half up first: wash the way you normally would, pat dry, put nothing on, and leave your face alone for a couple of minutes.
When does the tightness arrive? If it lands almost as soon as you've towelled off, does that every single time you wash, and settles once you moisturize, it's pointing at oil. If your face felt fine in the morning and feels tight by mid-afternoon under a moisturizer that seemed to be working, it's pointing at water.
Is it tight and shiny at once? Look at your T-zone at the end of the day. Visible shine plus a tight feeling is the dehydrated-oily pattern, and it's the one most often misread as "my skin is confused".
Squeeze a cheek. Press gently between two fingers. If fine lines crinkle up under the pressure and vanish the moment you let go, that's a water reading: fine lines that appear out of nowhere are one of dehydration's clearest signs. If instead the skin takes a beat to lie flat again after you release it, you're reading elasticity, which is a separate subject with a separate answer.
Look at the surface. Flaking you can see, roughness you can feel with a fingertip, and skin that cracks beside the nose belong to dryness. Dehydration more often reads dull and tight while the surface itself stays reasonably smooth.
Reading your result
Tight straight after washing, flaking, rough to the touch: an oil shortage. Your skin needs lipids put back, and something to soften and seal the surface.
Tight all day, dull, fine lines on the squeeze, shine in the T-zone: a water shortage. Your skin needs water pulled in and then held there, and a heavier cream on its own won't do it.
Both lists sound familiar? That happens a lot. Plenty of people with a dry type are dehydrated on top of it, and each one worsens the other: less oil means water leaves faster, and less water leaves the surface rougher. If you can't call it, run this experiment for a week. Put a hydrating serum under your usual moisturizer every day and change nothing else. A clear improvement means water was the missing piece.
Where this takes you
The next few steps in this course split along the line you just drew. If tightness is the thing you want gone, the lesson after this one explains what that feeling physically is and what speeds it up, which is often something already in your routine. If your answer was water, the humectant lesson later on is the one that matters most, because a hydrating layer applied the wrong way can leave you worse off than doing nothing. Either way, hold on to your result: nearly every product decision from here depends on knowing whether you're replacing oil, replacing water, or both.