How Often Should You Replace Mascara? A Safe Rule

How often should you replace mascara? For an opened tube used most days, three months is the best-supported practical limit. Replace it sooner after an eye infection, if someone else used it, or if its smell or texture changes. Follow any shorter date on the label. Never loosen dry mascara with water or saliva.

Why three months is the practical answer

A mascara wand touches your lashes, then returns to the same tube. That repeated contact can carry skin and lash microbes into the formula. Preservatives control growth, but they don't keep every opened tube sterile forever.

Pack and colleagues tested this process in a 2008 Optometry pilot study. Forty women aged 18 to 39 received one of two non-waterproof mascaras. They used it daily for three months, and 33 returned their tubes for culture. Researchers found microbial growth in 36.4% of them.

The organisms were mainly Staphylococcus epidermidis, Streptococcus species, or fungi. The team didn't count how much was present, and it didn't show that those microbes caused an infection. Only two formulas were tested. Still, it gives the three-month rule a real basis.

A larger UK study adds context. Bashir and Lambert cultured 467 donated, used cosmetics for the Journal of Applied Microbiology in 2020. Of the 93 mascaras, 79.6% grew bacteria on general nutrient agar. The researchers didn't assign people fresh tubes or standardise wear time, so this study cannot set an exact expiry date.

The US Food and Drug Administration's 2022 shelf-life guidance gives the usual manufacturer range as two to four months after purchase. Three months sits in the middle. It is a cautious deadline, not a claim that every tube becomes dangerous on day 91.

How to read the date on your mascara

First, look for an expiry date or an open-jar symbol. A mark such as “3M” means three months after first opening. UK government guidance updated in 2026 calls this the Period After Opening, or PAO. It covers the time the product should remain safe under normal use.

Write the opening date on the tube or set a phone reminder. A PAO clock starts at opening, while the FDA words its general range from purchase. If you bought a sealed backup, follow its printed expiry and storage directions. Once opened, use any shorter label limit.

A longer PAO does not cancel signs of contamination or a known exposure. A product-specific PAO reflects its formula and package. Yet the daily-use study only followed mascara for three months. It offers no evidence that occasional use makes six months safe.

If you cannot remember when you opened a tube, don't judge by smell alone. Microbial growth may not change its appearance. Replace it if you cannot place it confidently inside its safe window.

Keep it or toss it: a quick decision table

A practical mascara replacement check

What you notice	What it means	What to do	Limit
Opened less than three months ago, within its label period, with normal texture and smell	No obvious reason to shorten the window	Keep using it with clean hands and your own wand	This cannot prove the tube is sterile
Opened three months ago and used most days	It has reached the best-studied replacement point	Replace it	The evidence comes from 33 returned tubes and two formulas
Dry, clumpy, separated, or smells different	The formula has changed or degraded	Discard it now and do not add liquid	A normal-looking tube can still contain microbes
Used during an eye infection or inflamed eyelid episode	The wand may have picked up material from the affected area	Discard it and pause eye cosmetics until the area has healed	The mascara cannot tell you what caused the symptoms
Shared with another person or used as a shop tester	It has had contact with another person's microbes	Do not keep using it	Wiping the wand does not clean the product inside
Fresh tube that only smudges	This is usually a wear problem, not an expiry test	Check application, skin oils, and formula in the mascara smudging guide	Smudging alone does not show contamination

Five habits that reduce avoidable contamination

1. Wash and dry your hands before applying eye makeup. Keep the wand, cap, and tube opening clean.

2. Do not share mascara. Do not use a shop tester directly on your lashes, even if the product looks new.

3. Do not add water, saliva, oil, or remover to a drying tube. The FDA warns that water can introduce microbes and dilute preservatives. Saliva adds microbes from your mouth.

4. Keep mascara out of hot cars and direct heat. The FDA says heat can weaken preservatives and speed microbial growth.

5. Stop applying makeup in moving vehicles. One sudden stop can turn the wand into an eye injury.

Cleaning the visible wand cannot sanitise the formula inside an old tube. Replacing it on time is simpler.

What if mascara makes your eyes red or watery?

Stop using the product. Redness or watering can come from irritation, allergy, a scratch, or infection. The symptom alone does not identify the cause. Our guide to why makeup makes eyes water helps you check placement and likely irritants without guessing.

The FDA advises discarding eye cosmetics used when an infection occurred. Wait until the eye area has healed before using eye makeup again. If irritation persists, contact a healthcare professional.

Seek urgent eye care for severe pain, light sensitivity, vision changes, or severe redness. NHS guidance reviewed in 2025 lists those as urgent warning signs. Contact-lens wearers with a red, painful eye also need urgent assessment.

Does occasional use make mascara last longer?

We do not have a solid number. Pack's study tested daily use, while real products differ in preservatives, brushes, storage, and exposure. Less use may mean fewer contacts with your lashes, but it does not stop ageing after opening.

Use the printed PAO as the outside limit and replace sooner after contamination, heat, or formula changes. If the tube has no clear label, three months remains the cleanest rule. Buying a smaller tube can waste less product without stretching the safety window.