Eyeliner has two expiry dates. The first is printed on the pack: an open-jar symbol with a number of months, which tells you how long the formula stays stable and preserved once the seal is broken. The second is set by the eye itself. A pencil that touches the lid margin every morning, or a liquid whose brush goes back into its tube, collects bacteria from the skin.
The two dates disagree. Brands print 6 to 12 months for eye products. Eye-care professionals say 3. The gap is the difference between a formula that still works and a formula that is still safe next to the eye, and the second one wins.
How long does eyeliner last once opened?
An opened eyeliner lasts as long as its preservative system keeps bacteria and mould in check, which the PAO symbol states as 6 or 12 months for most eye products. The eye-care advice is shorter. Vision Care Ottawa, an optometry practice, gives 3 months for both liquid and pencil eyeliner and 2 to 3 months for mascara, and notes that liquid liner's water content makes a moist environment where bacteria grow (Vision Care Ottawa).
| Format | Typical PAO on the pack | Eye-care advice | Signs to throw it away |
|---|---|---|---|
| Liquid pen, felt tip | 6 to 12 months | 3 months | Tip frays, line skips, smell changes |
| Liquid, brush tip in a tube | 6 to 12 months | 3 months | Formula thickens in the tube, brush stiffens, dried crust at the neck |
| Gel pot | 6 to 12 months | 3 months; open pots dry fastest | Surface hardens, cracks, colour looks dull |
| Gel or kohl pencil, sharpenable | 12 months or more | 3 months if used on the waterline; sharpen before each use | White film on the tip, hard core, drags on the skin |
| Retractable pencil | 12 months | 3 months if used on the waterline; wipe the tip before each use | Tip dries and crumbles, mechanism sticks |
A pencil lasts longest because it contains no water (anhydrous): waxes, oils and volatile silicones give bacteria nothing to live in, and the tip can be cut away. A water-based liquid and an open gel pot are the most vulnerable formats.
What does the PAO symbol on eyeliner mean?
The period-after-opening (PAO) symbol is an open jar printed with a number and the letter M, and it states how many months a cosmetic can be used after first opening without harm to the user. Under Article 19 of the EU Cosmetics Regulation (EC) No 1223/2009, a product with a minimum durability of more than 30 months must carry the PAO symbol; a product that lasts less than 30 months is printed with a best-before date instead (EUR-Lex, Regulation 1223/2009).
The number is the brand's judgement, based on preservative testing, of how long the formula stays stable in normal use. It measures the formula, not the eye. A 12M pencil is still a stable pencil at month eleven. It is not still a clean one if it has been on the waterline every day, and the regulation does not claim otherwise.
Write the opening date on a strip of tape on the cap. The PAO only means something if you know when the clock started.
Why do eye doctors say three months?
The eye is warm and wet, and so is the tip of an eyeliner after use. Specialty Vision, an eye-care information site, describes the waterline as a warm, moist environment where bacteria thrive, and explains that applying a pencil there repeatedly transfers organisms from the product to the eye and back, with conjunctivitis, styes and corneal infections as the risks (Specialty Vision). Its advice is to replace all eyeliner products every three months.
Optometrist Dr Alexa Hecht applies the same logic to mascara: every month, three months at most, whatever is left in the tube, because each dip takes bacteria back inside (Coveteur). In Optometry Times, Brittany Mitchell, an optometrist, adds that a tube should be replaced at once if conjunctivitis develops (Optometry Times). Liners that go into the same tube on a brush follow the same rule.
The waterline is the reason the advice is strict. Dr Hecht warns that product on the rim blocks the meibomian glands along the lid margin, which make the oily part of the tear film; blocked glands thicken their oil and contribute to dry eye and blepharitis.
How do you sharpen an eyeliner pencil to keep it clean?
You will need
- A sharpener with a blade that matches the pencil's diameter, and a second hole if the brand uses a wider barrel
- Cotton pads and rubbing alcohol (isopropyl alcohol) or micellar water
- A tissue
- A refrigerator, for very soft gel or kohl pencils
- Clean the sharpener. Wipe the blade and the cone with a cotton pad dampened with alcohol, and let it dry. A dirty sharpener puts old pigment back on a fresh tip.
- Chill a soft pencil for 10 to 15 minutes. A cold core cuts cleanly; a warm one crumbles and clogs the blade.
- Turn the pencil, not the sharpener, with light pressure, until a fresh surface shows along the whole tip. Two or three turns is usually enough.
- Wipe the new tip once with a tissue to remove loose shavings, then draw a short test line on the back of the hand.
- Sharpen again before each use on the waterline. Specialty Vision's rule is to sharpen before every use to remove the contaminated outer layer of product.
- Cap the pencil straight after use. Air dries the tip and a bare tip picks up whatever is in the make-up bag.
A retractable pencil cannot be sharpened, so it needs wiping instead. Twist up a little, wipe the exposed tip with a clean tissue before and after use, and twist it back down. If a retractable was used on the waterline, treat it as a 3-month product, whatever the PAO says.
Why do liquid liner tips dry out, and what helps?
A felt-tip pen dries because its reservoir is water-based and every second with the cap off lets water evaporate through the tip. A brush-tip liquid dries because formula left on the brush hardens at the neck of the tube and thickens what is inside. A dried liquid liner does not come back.
Cap the pen the moment the line is drawn, and press until it clicks. Store a felt-tip pen horizontally or tip down so the reservoir stays in contact with the tip. Wipe the neck of a brush-tip tube with a tissue once a week so the cap seals on clean plastic. Keep both away from a sunny windowsill and a steamy bathroom shelf, since heat speeds evaporation and moisture feeds bacteria.
Do not add water, saline or eye drops to a drying liner. Water dilutes the preservative, changes the film, and introduces whatever was in the dropper. A pen that skips after three months has done its job; replace it.
Which hygiene rules apply to every eyeliner?
- Wash your hands before applying liner, and dry them on a clean towel.
- Never share an eyeliner, even with family. Specialty Vision states the rule without exceptions, and a shared pencil is a shared infection.
- Apply liner in a still room, not in a moving car, bus or train. A jolt puts the tip on the cornea.
- Keep liner off the waterline as a daily habit. Line under the lower lashes and into the base of the upper lashes; Dr Hecht recommends lining under the lashes for the same effect with the glands left open.
- Clean a gel-pot brush after each use with a little brush cleanser or micellar water, and never dip a brush that has touched the eye back into the pot without cleaning it.
- Remove liner fully every night. Pigment left on the lid margin overnight blocks the glands and irritates the eye.
- Throw away every eye product you used during an eye infection, and start again with new ones once the eye has cleared.
A smaller pencil or a mini liquid, finished within three months, is easier on the budget than binning a large one half full.
When should you see an optician about eyeliner?
See an optician or optometrist if the eye feels dry, burns or stings after liner, if vision blurs during the day, or if the lid margin is red and crusted in the morning. Specialty Vision's advice for dryness, burning or blurry vision after wearing eyeliner is to have the tear film and the meibomian glands checked (Specialty Vision). A stye, which is a painful lump on the lid, or a sticky, red eye with discharge needs a GP or optician the same week.
Contact lens wearers should see their optometrist if a lens feels gritty after make-up, since lenses can trap migrated liner particles against the cornea. Stop wearing liner on the waterline until the eye is checked.
“When you're putting products on your waterline, you're basically blocking those glands.”
Dr Alexa Hecht, Optometrist, quoted in Coveteur
- The PAO symbol on eyeliner says 6 to 12 months; eye-care professionals say 3 months, and 3 at most for anything used on the waterline.
- Pencils last longest because they contain no water and the tip can be sharpened away; liquids and open gel pots are the most vulnerable.
- Sharpen a pencil before every waterline use with a sharpener cleaned in alcohol, and wipe the tip of a retractable before and after.
- Cap liquids straight away, store felt tips horizontally or tip down, and never add water to a drying pen.
- Never share liner, remove it fully every night, and throw all eye make-up away after an eye infection.
Questions people ask
How long does eyeliner last once opened?
By the PAO symbol, 6 to 12 months for liquids and gel pots and 12 months or more for pencils. Optometry sources advise 3 months for liquid and pencil liner, and 3 months at most for anything used on the waterline. Replace it sooner if the tip frays, the smell changes or the formula thickens.
Does eyeliner expire if unopened?
Slowly. A sealed product with a PAO symbol has a minimum durability of more than 30 months under EU rules, so an unopened pencil or liquid kept cool and out of sunlight is fine for two years or more. The PAO clock starts on the day you open it.
Can you sharpen a retractable eyeliner?
No. A retractable has a fixed core that twists up and down. Wipe the exposed tip with a clean tissue before and after each use, and replace the pencil after 3 months if it has been on the waterline.
How do you know if eyeliner has gone bad?
A pencil grows a white film, goes hard or drags. A liquid skips, thickens or smells different. A gel pot cracks or dries on top. Any of these means the product has changed, and it goes in the bin.
Can old eyeliner cause an eye infection?
Yes. Bacteria from the skin and the waterline live on the tip and in the tube, and each use moves them back to the eye. Conjunctivitis and styes are the usual results. After any eye infection, throw away every eye product you used and start again.
- Vision Care Ottawa, Eye makeup lifespans and your ocular health
- EUR-Lex, Regulation (EC) No 1223/2009 on cosmetic products
- Specialty Vision, Dangers of applying eyeliner to the waterline
- Coveteur, What eye makeup is doing to your eye health, with optometrist Dr Alexa Hecht
- Optometry Times, 7 tips for safer lens wear with cosmetics, by Brittany Mitchell OD
- Ophthalmology Advisor, Improper eyelid cosmetic hygiene can lead to ocular surface disease and infections