A tube of gloss is a small jar of oils and polymer with a wand that goes from the mouth to the tube and back several times a day. Everything on the lips, from coffee to the bacteria that live around the mouth, ends up in the formula. The preservative system copes with this for a fixed time, printed on the pack, and then it does not.
The rules on that time, the way to read the symbol, what a 2019 laboratory study found in used lip glosses, and the signs that a tube has gone off are set out with their sources. The short version is 12 to 24 months once opened, no sharing, and a bin for anything that smells different.
Does lip gloss expire?
Yes. A gloss has two lives, one sealed and one open. Under the EU cosmetics regulation, a product that keeps for more than 30 months unopened does not print a best-before date. It prints the period after opening (PAO), the length of time the product is safe to use once the seal is broken, next to an open-jar symbol (Regulation (EC) 1223/2009, Article 19). A product that keeps for less than 30 months prints a best-before date instead.
Most glosses print 12 M or 24 M. The number is the manufacturer's own limit for the preservative system, the oils and the applicator once air and mouth bacteria are in the tube. Unopened and kept cool and dry, a gloss keeps for two to three years, according to Kaja Beauty, and the brand advises binning an opened gloss after 12 to 18 months.
The United States has no equivalent rule. The US Food and Drug Administration (FDA) states that no US law requires cosmetics to state shelf lives or expiration dates, and defines shelf life as the time a product can be expected to look and act as expected and stay safe. A gloss bought from a US brand may show no date at all, so the open date has to be your own.
How do you read the open-jar symbol?
The open-jar symbol is a small drawing of a jar with its lid lifted, with a number and the letter M inside or beside it. The M is months. 12 M means the gloss is safe for twelve months after the first use. The symbol is set out in Annex VII of the EU regulation, and it appears on the tube, the box or both.
The clock starts at first opening, not at purchase, so the useful habit is to write the month you opened it on the base of the tube with a fine marker. A gloss opened in September 2026 with a 12 M symbol is finished in September 2027. Three other marks on the pack help: the batch number, which every EU cosmetic must show so a product can be traced, the ingredient list in the international nomenclature of cosmetic ingredients (INCI), and, on shorter-life products, the hourglass symbol with a best-before date.
Why does the applicator matter so much?
A doe-foot wand is a small sponge on a stick that touches the lips, then goes back into the formula, then touches the lips again. Every cycle moves bacteria from the mouth into the tube. The FDA notes that applicators which return to the container pick up bacteria with each use, and that preservatives break down over time, so an old gloss is both more contaminated and less protected than a new one.
Researchers at Aston University measured this. A 2019 study in the Journal of Applied Microbiology tested used lipsticks, lip glosses, eyeliners, mascaras and makeup sponges and found that 79 to 90% of all used products were contaminated with bacteria, including Staphylococcus aureus and Escherichia coli, with fungi and Enterobacteriaceae found in every product type (Aston University). The authors concluded that the pathogens found pose a potential risk to health, most of all when products are used near the eyes, the mouth or broken skin.
The practical answer is a squeeze tube, a stick gloss or a wand that is wiped. A squeeze tube with a slanted tip never returns product to the reservoir. A wand can be wiped with a clean tissue before it goes back in the tube. Neither habit makes a gloss last beyond its PAO, but both slow the build-up.
Can you share lip gloss?
No. The FDA advises against sharing makeup at all, on the grounds that sharing a product can mean sharing an infection. For lip products the specific risk is the cold sore virus, herpes simplex. The NHS states that cold sores are contagious from the moment of the first tingle until the sore has fully healed, and that they spread easily to other people. A gloss wand used on a lip with an early cold sore moves the virus into the tube, where it can reach the next user.
Shop testers follow the same rule. Use a disposable applicator, or ask for a clean spatula and take gloss from the tube onto the back of the hand. Never apply a tester wand to the lips. If you have a cold sore, keep a separate gloss for the duration and bin it when the sore has healed, because the wand has been dipping into a live infection for a week or more.
The NHS advises seeing a pharmacist for cold sore creams and patches, and a GP if a sore has not started to heal within 10 days, is very large or painful, or keeps returning.
How do you tell a lip gloss has gone off?
The PAO is a maximum. Heat, sunlight, a dirty wand or a cheap preservative system can finish a gloss earlier. The senses catch it before the date does.
| Sign | What it means | What to do |
|---|---|---|
| Smell has changed, crayon-like or sour | Plant oils have oxidised (gone rancid) | Bin it |
| A clear oil layer on top, or the gloss looks split | The emulsion or oil blend has separated | Bin it; shaking does not fix the chemistry |
| Gritty or lumpy on the lips | Pigment or pearl has clumped, or the base has thickened | Bin it |
| Colour has darkened or faded | Pigment and oils have reacted with light and air | Bin it |
| Stringy, thick or dried at the neck | Volatile parts have evaporated; the tube has been open too long | Bin it |
| New tingling, stinging or a rash | Irritation from a degraded formula or contamination | Stop use; see a GP if the rash lasts |
| Past the PAO but looks and smells fine | The preservative can no longer be relied on | Bin it |
Glosses built on natural plant oils go rancid sooner than those built on polybutene and synthetic esters, because unsaturated oils oxidise. A rosehip or raspberry seed oil gloss is one to open and finish, not to keep in a drawer.
How do you store lip gloss to make it last?
Storage decides whether a gloss reaches its PAO. The FDA lists heat, sunlight and exposure to air as the causes of changes in colour, texture and smell, and names a hot car as the place to avoid. Oils oxidise faster when warm, and pearl and pigment settle when a tube is left on its side in the sun.
Four habits
- Keep gloss in a drawer or a bag, away from the bathroom windowsill and the car.
- Close the cap fully after each use. Air at the neck dries the gloss and lets the wand pick up dust.
- Wipe the wand on a clean tissue before it goes back in, and wipe the neck of the tube once a week.
- Never add water or saliva to a dried gloss to loosen it. The FDA gives this warning for mascara, and the reason is the same: it introduces bacteria into a formula that is already tired.
A fridge is not needed and can make polybutene glosses too thick to spread. Cool room temperature, out of the light, is enough. With these habits a 24 M gloss stays usable for its two years, and a 12 M gloss for its one. A similar routine keeps nail polish usable, set out in how to store nail polish.
“Consumers' poor hygiene practices when it comes to using make-up, especially beauty blenders, is very worrying”
Dr Amreen Bashir, School of Life and Health Sciences, Aston University, quoted by ScienceDaily
- EU law puts a period-after-opening symbol on any gloss that keeps more than 30 months unopened; most glosses print 12 M or 24 M.
- A 2019 Aston University study found 79 to 90% of used lip and eye products contaminated with bacteria, including Staphylococcus aureus and E. coli.
- A wand that goes from lips to tube moves mouth bacteria into the formula, so wipe it and never share a gloss.
- Cold sores are contagious from the first tingle until healed, so keep a separate gloss during an outbreak and bin it afterwards.
- A changed smell, a separated oil layer, grit or a new sting means the gloss is finished, whatever the date.
Questions people ask
How long does lip gloss last after opening?
Twelve to twenty-four months for most glosses, shown by the open-jar symbol with 12 M or 24 M on the pack. Write the opening month on the tube. A gloss that smells or looks different before then is finished early.
Can you use expired lip gloss?
It is not worth it. After the period after opening the preservative can no longer be relied on, and the oils may have oxidised. An old gloss can cause irritation, spots around the mouth or a rash. A gloss that has also changed smell or texture should go straight in the bin.
Is it safe to share lip gloss?
No. The FDA advises against sharing any makeup, and the NHS notes cold sores are contagious from the first tingle until fully healed. Use a disposable applicator on testers and keep your own gloss to yourself.
What does 12M on lip gloss mean?
It is the period after opening, shown inside or beside an open-jar symbol. 12 M means the product is safe for twelve months from the day you first open it, when stored as intended. It is required in the EU for products that keep more than 30 months unopened.
How do you know if lip gloss has gone bad?
The smell changes first, often to a crayon or sour note as the oils oxidise. A clear layer of separated oil, grit on the lips, a darker colour, a stringy texture or a new tingle are the other signs. Any one of them means the tube should go.
- Regulation (EC) No 1223/2009 on cosmetic products, Article 19 and Annex VII
- US Food and Drug Administration, Shelf life and expiration dating of cosmetics
- Aston University, Microbiological study of used cosmetic products (Journal of Applied Microbiology, 2019)
- ScienceDaily, The deadly superbugs lurking in more than nine in ten make-up bags
- NHS, Cold sores
- Kaja Beauty, How long does lip gloss last?