How long mascara really lasts, and when to bin it

Most people's mascara is older than it should be. Ask when it was bought and the answer is usually vague: sometime before the summer, perhaps last winter. The tube still works, so it stays.

The usual advice is to replace it every three months. That figure comes from eye-health bodies and manufacturers, and it is a cautious convention rather than a measured cut-off. There is no day on which a tube turns hazardous. But the reasoning behind it holds up, and it is worth knowing why.

Why mascara is different from other makeup

Every time you pull the wand out, you put it against your lashes and lids, then back into a dark, slightly damp tube. That transfers skin bacteria into the formula. Preservatives slow their growth but do not stop it, and they weaken over time as the tube is opened again and again.

Studies that have swabbed in-use mascaras and other eye products have found bacterial contamination in a meaningful share of them, and the risk rises with age and with how long they have been in use. Most contamination causes nothing at all. The concern is that the product sits next to the eye, where a scratch from a clumped wand can give bacteria a way in. Styes and conjunctivitis are the usual worries.

Price makes little difference here. All mascaras rely on the same kind of preservatives, and there is no good evidence that a £25 tube stays safe longer than a £6 one.

What shortens a tube's life

Pumping the wand. It pushes air into the tube, which dries the formula faster. It does not load more product onto the wand. Twist it inside the tube instead.

Adding water or saliva. Both introduce new bacteria and dilute the preservatives. A dry mascara cannot be safely revived, so bin it.

Sharing. Other people's skin bacteria are not the ones your eyes are used to. Shop testers fall into the same category.

Warm rooms. A steamy bathroom or a bag left in a hot car speeds up drying and microbial growth. A drawer in a cooler room is better.

Signs it is finished

Date matters, but so does the product itself. Replace it sooner if:

it smells sour or different from when it was new
it has gone clumpy or flaky and no longer coats evenly
it is visibly dry on the wand
your eyes feel gritty, sting or look red after wearing it

After an eye infection, throw away every eye product you used on that eye, including liners and shadows. If your eye is red, sore or producing discharge, see a pharmacist or doctor.

The rest of the eye bag

Mascara gets the attention, but the same logic applies to other eye products, with different timings.

Liquid and gel eyeliner: about three months, for the same reason as mascara. They are used right at the lash line and the tubes or pots are reopened constantly.
Pencils: sharpen before each use. The wood trims away the surface that has touched your skin, so pencils last longer, often a year or so.
Cream shadow: six to twelve months.
Powder shadow: often a year or more, since dry powder is a poor place for bacteria to grow. Wipe or replace the sponge applicator, or use a brush.

Look on the packaging for a small open-jar symbol with a number and the letter M, such as 6M. It means six months after opening. When it is there, it is more reliable than a rule of thumb.

Making the date stick

The reason tubes get old is that nobody remembers when they were opened. The fix is dull but effective. Write the month on the bottom of the tube with a marker, or put a phone reminder in the calendar the day you open a new one.

If three months feels wasteful, buy cheaper mascara and replace it on schedule. That beats an expensive tube kept for a year.

What to do this week

Check every mascara and liquid liner you own. If you cannot say when you opened it, bin it.
Write the opening month on the bottom of each new eye product.
Stop pumping the wand. Twist it in the tube instead.
Sharpen your eye pencils before using them.
Look for the open-jar symbol on your other eye products and replace anything past its date.