Most menstrual cup instructions say the same thing: rinse it during your period and sterilize it at the end. But how often is often enough? Do you need to boil it every time you empty it? And how long should you boil it without damaging the silicone? This guide answers all three, using what the research actually says.
If you are setting up your cup routine for the first time, the Pee Safe menstrual cup range has combos with a sterilizing container, so you have everything in one go.
Quick answer
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Is it necessary to sterilize a menstrual cup? Yes. Rinsing removes blood but does not kill all germs.
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How often? Before first use, and at the end of every period as a minimum. Many people also sterilize at the start of each period.
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Every time you empty it? No. During your period, rinse it with water and wash it with a mild cup wash. Sterilizing every few hours is not needed for most people.
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How long to boil it? 5 to 7 minutes in rolling boiling water for Pee Safe cups. Follow your brand's instructions for other cups.
Is it necessary to sterilize a menstrual cup?
Yes, and here is why. A menstrual cup is worn inside your body for up to 12 hours, then stored for three to four weeks between periods. Washing with water removes blood and residue, but it does not reliably remove bacteria.
A 2018 lab study published in Applied and Environmental Microbiology tested how Staphylococcus aureus, the bacterium behind toxic shock syndrome (TSS), grows on tampons and menstrual cups. The researchers found that a layer of the bacteria (a biofilm) stayed on the cups even after 8 hours and three washes with water. They suggested that users keep a second cup, so one can be sterilized by boiling while the other is in use.
That was a lab test, not a study of real users, and TSS from a cup is rare. A 2019 review in The Lancet Public Health found only five reported cases of TSS after cup use across all the studies and safety reports it reviewed. But the lab finding is a good reason not to skip sterilizing. Read more in menstrual cups and toxic shock syndrome.
How often should you sterilize your menstrual cup?
The standard routine (enough for most people)
|
When |
What to do |
Why |
|---|---|---|
|
Before the very first use |
Sterilize |
Removes anything from manufacturing and packing |
|
Every time you empty it (every 4–12 hours) |
Rinse in cold water, then wash with a mild, unscented cup wash |
Removes blood and residue before reinserting |
|
At the end of each period |
Sterilize, dry fully, store in a breathable pouch |
Kills germs before 3–4 weeks of storage |
|
At the start of the next period |
Sterilize again |
Clears anything picked up during storage |
This means about two sterilizing sessions a month, each taking a few minutes.
The extra-safe routine: two cups
If you want to follow the lab study's advice more closely, keep two cups. Wear one while the other is sterilized and dried, and swap them once a day (or each time you change). This also helps if:
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you have heavy periods and empty your cup often
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you have had thrush or bacterial vaginosis before
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you travel or use public toilets often, where washing is harder
A pack of two Pee Safe menstrual cups makes this routine easy and costs less per cup than buying them one at a time.
Do I have to boil my menstrual cup every time I empty it?
No. For most people, rinsing and washing between uses is enough, with full sterilizing at the start and end of each period. Sterilize mid-period too if:
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the cup falls on the floor or into the toilet
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you have had a vaginal infection during this period
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someone else has handled it
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it smells unusual after washing
How long should you boil a menstrual cup?
For Pee Safe cups: 5 to 7 minutes in rolling boiling water. Most 100% medical-grade silicone cups need a similar time. Always check your own cup's instructions.
How to boil a menstrual cup the right way
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Rinse the cup in cold water first. Hot water can set blood stains.
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Use a small pot kept only for your cup, not one you cook in.
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Bring the water to a rolling boil, with enough water to cover the cup fully.
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Put the cup in a steel whisk or tea strainer, or keep stirring, so it does not touch the bottom or sides of the pot and scorch.
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Boil for 5 to 7 minutes. Set a timer.
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Lift it out with clean tongs, let it cool, and air-dry it completely before storing.
Do not boil it for much longer than needed. Very long or very frequent boiling can make silicone dull, sticky or less springy over time, which shortens its life.
No stove? Use steam or the microwave
If boiling is not practical, a menstrual cup steam sterilizer does the job in 3 to 5 minutes and switches itself off. A foldable sterilizing container works in the microwave in 2 to 3 minutes. See our full guide on how to sterilize a menstrual cup without boiling.
Signs your cup needs replacing, not just sterilizing
Sterilizing keeps a cup safe for up to 5 years. Replace it sooner if it:
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has a crack, tear or hole
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feels sticky, tacky or powdery
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has become thin or lost its shape
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still smells after sterilizing
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has white or dark patches that do not wash off
Read menstrual cup odour explained if smell is the issue.
The simple rule
Rinse and wash every time you empty it. Sterilize at the start and end of every period. For extra peace of mind, keep two cups and sterilize one while you wear the other. A few minutes twice a month keeps your cup safe and fresh for up to 5 years.
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