It is a quarter to eleven. Cleanser, toner, moisturizer, done. Then the sleeping mask goes on, it feels a little tacky, and you stop with one hand near the tap. Is this the kind you wash off, like the clay mask from Sunday? You leave it, turn the light off, and in the morning there is a faint shiny patch on the pillowcase and a new question: wash your face before sunscreen, or put the sunscreen straight on top?

Part of the confusion is the word itself. Almost everything else sold as a mask comes off after ten or twenty minutes. Clay gets rinsed, a sheet gets peeled away. So some people rinse the sleeping mask before bed, which turns it into a twenty-minute mask. Others decide that leaving it on means more is better, and spread a thick layer over a rich night cream and a few drops of face oil. The pillowcase gets a good share of that.

The packaging doesn't always help. Plenty of sleeping masks print two instructions that look like they disagree: "no need to wash off," then a line later, "rinse in the morning." Both are right, because they are about different times. A sleeping mask is the last thing you put on at night, and it is meant to stay on until you wake up. The morning rinse clears whatever is still sitting on the surface before the day's products go on.

What a sleeping mask is doing while you sleep

Your skin gives water to the air around it all the time. During the day you hardly notice, because you keep moving, drinking and reapplying things. At night you lie still for seven or eight hours in the same air, and once the heating comes on, that air gets dry. Nobody gets up at 3am to put on more moisturizer.

Moisturizers slow that water loss a little. A sleeping mask is a leave-on layer made to go on last and stay there through the night. Most are a gel or a gel-cream, lighter than a balm, so they can absorb instead of sitting on the surface. It goes last for the same reason sunscreen goes last in the morning: anything you put over it would just sit on it.

It helps to sort masks by what the directions tell you to do at the end. Clay, mud and cream masks stay on for a set time, often ten to twenty minutes, and then get rinsed off. Sleeping in one is a bad idea. Sheet masks come off when their time is up, and you pat in whatever liquid is left. Sleeping masks stay on until morning and come off with your morning wash.

Why rinse at all, if it was meant to stay on? By morning, whatever is left on your face has spent the night with sweat, a little oil and the pillowcase. Lukewarm water takes that off and gives your sunscreen a clean surface. Sunscreen spread over a tacky leftover film is also more likely to roll up into little crumbs once you start blending makeup on top.

The bigger question is whether you need one. If you wake up and your skin feels comfortable, your night cream is already handling the night, and a sleeping mask on top is one more layer with nothing to do. If your cheeks feel tight before you have even washed your face, or the sides of your nose look flaky most mornings despite moisturizer, a final layer at night has a job.

What to check before you buy one, or before tonight

Read how the directions end. Some products called masks are meant to come off after fifteen or twenty minutes, and those should not stay on overnight, whatever the box looks like. A sleeping mask tells you to leave it on, or to go to bed with it.

Look at where it sits in the routine. Most sleeping masks say "last step," which means on top of your moisturizer, so the total amount on your face goes up. If your night cream is already rich, pick a light gel mask, or save the mask for the nights your skin feels driest.

Think about the pillow before you think about ingredients. A gel or gel-cream sinks in further than a thick balm, and timing matters as much as texture. Put it on while you still have ten minutes of reading left, rather than as the last thing before the light goes out, and less of it ends up on the pillowcase.

Decide how you want to measure it. A jar lets you use a little on two dry patches and more on a bad night, but you guess the amount every time, and it is easy to guess high. Single-dose sticks or packets set the amount for you, and you give up the option of using less.

Check the line about eyes. Many sleeping masks say to keep away from the eye area, so if you wanted one product for under your eyes too, find that line first.

For a longer look at what belongs in a night routine and what belongs in the morning, here is a video from a channel we have no connection with. It is their view, not ours, and we have not summarized what they say in it.

Video: Morning vs. Night Skincare: What Really Matters / Dr Dray. Not affiliated with BRAND KR.

Where the SNP sleeping pack fits

The sleeping mask we stock is the SNP Gold Collagen Sleeping Pack. It comes as 20 individually wrapped sticks of 4 ml each, 80 ml in total, and the box is printed with "one stick a day" in Korean. The product page calls it a gel-type cream and says it absorbs without staining your pillow. It lists the key ingredients as 24K gold, hydrolyzed collagen, adenosine and glycerin.

Its directions line up with everything above. Open one stick as the final step of your evening routine, spread the whole 4 ml over your face and neck while avoiding the eye area, and go to sleep without washing it off. The next morning, rinse lightly with lukewarm water. It is made in South Korea by SD Biotechnologies, the company behind SNP, and a box of 20 costs 11.80 USD. Shipping and duties are calculated at checkout.

Who this suits

• Your skin feels tight when you wake up even after moisturizer, and you want one more layer at night without guessing how much to use.
• You often sleep away from home. Each stick is sealed on its own, so a few can go in a toiletry bag and the jar stays home.
• Your neck usually gets whatever is left on your fingers. The directions send the 4 ml to face and neck both.

Who can skip it

• Your skin already feels comfortable in the morning with the night cream you have. A sleeping mask would have nothing to add.
• You want something for under your eyes. The directions say to avoid the eye area.
• You only want a dab on one or two dry spots. Each stick is meant to be used whole.

How to use it

1. Finish the rest of your evening routine first: cleanse, then whatever you normally put on. The sleeping pack goes last.
2. Tear open one stick and spread all 4 ml evenly over your face and neck. Keep it away from the eye area.
3. Leave it on and go to sleep. If you can, give it a few minutes to absorb before your face meets the pillow.
4. In the morning, rinse lightly with lukewarm water, then go on with sunscreen and the rest of your morning routine.
5. Use one stick per night. A box of 20 covers twenty nights.
6. If your skin stings or turns red after using it, stop.

The same directions are on the product page.

What it can't do

It can't be used a little at a time. The directions ask for the whole 4 ml stick on face and neck, and once a stick is torn open there is no cap to put back on. If your face simply takes less than that, or your skin only gets dry in two spots, part of every stick goes to waste. A jar suits that kind of routine better. The stick trades flexibility for a set amount and easy packing.

If you are not sure you need a sleeping mask at all, spend a week noticing how your face feels in the first minute after you wake up, before water touches it. It is easy to miss, because the face usually gets washed before you think of it. If it feels tight on most of those mornings, a final layer at night is worth trying, and the SNP stick pack is the one we carry for it.