How to Sterilize a Menstrual Cup: Microwave, Pot or Tablets

Did you know you can sterilize your menstrual cup in just 3 minutes without having to watch a pot on the stove? Many people still boil their cup “by eye” in the same pot they cook with, when faster methods exist that are gentler on the silicone and perfect for when you’re traveling without a kitchen nearby. Here are the three real methods — microwave, pot, and tablets — explained step by step, with exact times and no myths.

Why you need to sterilize your menstrual cup (and when)

The menstrual cup doesn’t need sterilizing every time you empty it during the day: rinsing it with water and, if you have some, a bit of mild intimate soap is enough. Thorough sterilizing is reserved for two moments: at the start and end of each cycle. It’s a preventive hygiene step, not a daily requirement, and that’s exactly what manufacturer and healthcare professional usage guides say too.

The scientific evidence supports that a well-cared-for menstrual cup is a safe option: the systematic review and meta-analysis published in The Lancet Public Health (van Eijk et al., 2019), covering 43 studies and over 3,300 participants, concludes that the menstrual cup has an adequate safety profile and leakage rates equal to or lower than tampons and pads. That safety profile largely depends on keeping up proper hygiene: washing after each emptying and sterilizing between cycles.

Method 1: sterilizing a menstrual cup in the microwave

This is the fastest method if you have a foldable sterilizer like the Sileu Clean (€12.99) at home. Made from German Wacker silicone, certified ISO 10993 (surgical-medical grade), it handles microwave heat perfectly without warping. The process:

1. Fill the sterilizer with water until the cup is covered.
2. Place the menstrual cup inside, already washed with water and mild soap.
3. Close the lid without sealing it tightly (let steam escape) and put the sterilizer in the microwave.
4. Heat for 3-5 minutes at medium power (600-800W). The water should reach a boil inside the container.
5. Let it cool for a few minutes before taking the cup out: both the plastic and the silicone hold heat.

Never put the cup in the microwave alone, without water: the silicone can burn or degrade from direct contact with the metal of some turntable bases or from localized overheating. Always use a microwave-safe container with water, like the Sileu Clean sterilizer, designed exactly for this.

Method 2: sterilizing a menstrual cup by boiling it in a pot

It’s the most affordable method and requires buying nothing. You need a pot you set aside just for this (for hygiene, better not to use your regular cooking pot the same day) and enough water for the cup to be fully submerged without touching the bottom directly:

1. Fill the pot with enough water for the cup to float without touching the bottom (you can place it inside a metal strainer or a silicone egg holder).
2. Bring the water to a boil.
3. Add the cup and boil for 5-10 minutes from when the water returns to a boil.
4. Remove it with clean tongs, never reaching your fingers directly into the boiling water.
5. Let it air dry on a clean cloth before storing it.

Watch out for two common mistakes: letting the cup touch the bottom of the pot directly (it can burn at the contact point) and over-boiling “just in case.” More than 10-15 minutes adds no extra hygiene and just speeds up long-term silicone wear.

Method 3: sterilizing a menstrual cup with tablets, no hot water needed

When you have no access to a stove or microwave — camping, an overnight train, a shared office bathroom — Milton sterilizing tablets (€2.99) are the most practical alternative. They work through cold chemical disinfection:

1. Dissolve a Milton tablet in cold or lukewarm water (never hot: it would lose effectiveness), following the ratio stated on the package.
2. Submerge the already-washed cup in the solution for 15 minutes.
3. Take the cup out and rinse it with clean water before using it again.

It’s the ideal method for traveling with a menstrual cup, because a box of tablets takes up the same space as a regular pill blister and doesn’t depend on finding an outlet or an available kitchen.

Comparison: which method should you choose based on your situation?

	Microwave	Pot	Milton tablets
Time	3-5 min	5-10 min	15 min soaking
Cost	Sterilizer €12.99	€0 (just water)	€2.99 for the tablets
Best for	Home, quick routine	No sterilizer on hand	Travel, no stove or microwave
Requires	Microwave + sterilizer	Stove + dedicated pot	Just cold or lukewarm water

If we had to pick just one method for everyday use, it would be the microwave with the Sileu Clean: it’s the fastest and uses the least energy and water. But also packing Milton tablets in your travel bag is the lightest backup solution out there. In fact, this is exactly the combination included in the Sileu Travel Pack: cup, foldable sterilizer and pouch in one pack for €29.99.

Common mistakes when sterilizing a menstrual cup

After years answering customer questions, here are the mistakes that come up most often:

• Using bleach or alcohol. Both degrade medical-grade silicone and can leave irritating residue. There’s no need anyway: water, mild soap and heat (or specific tablets) are enough.
• Sterilizing too often. Doing it daily “just in case” wears out the silicone prematurely without any extra hygiene benefit over daily washing with water and soap.
• Not drying it properly before storing. Storing a damp cup in its cotton pouch traps moisture. Always let it air dry for a few minutes first.
• Confusing sterilizing with washing. What you do several times a day (rinsing) doesn’t replace start- and end-of-cycle sterilizing, and vice versa: you don’t need to boil the cup every time you empty it.

If you also use OEKO-TEX Standard 100 certified organic cotton period underwear (free from harmful substances), remember its hygiene routine is different: it’s machine washed, never boiled or put in the microwave.

What if you’re worried about an infection or toxic shock syndrome?

Proper sterilizing is also your first line of defense against concerns like toxic shock syndrome (TSS) associated with menstrual cup use, an extremely rare condition, but one whose warning signs (sudden high fever, rash, intense dizziness) are worth knowing so you can seek emergency care if they appear. Keeping the cup clean, sterilized at the start and end of each cycle, and not wearing it longer than the manufacturer’s recommended hours are the most effective preventive measures you can control yourself. For any symptom that worries you, see your gynecologist: this article doesn’t replace a medical evaluation.

Does heat or the tablets damage silicone in the long run?

It’s a reasonable question, especially if you’re used to disposable products where “heat” sounds like a bad idea. With medical-grade silicone, the opposite is true: it’s designed to withstand repeated sterilizing temperatures without losing elasticity or changing color, as long as you don’t expose it to direct heat without water (like setting it on a hot pan) or abrasive products. What does wear down any silicone over time, no matter how you sterilize it, is normal use: years of folding, inserting and washing. That’s why it’s recommended to check your cup’s condition every few cycles — a sticky texture, fine cracks, or a persistent change in odor are signs it’s time to replace it, not a failure of the sterilizing method.

Something similar happens with Milton tablets: they’re a low-concentration chlorine solution designed specifically for medical equipment and baby bottles, so they’re gentle on silicone as long as you follow the ratio on the package and rinse the cup well with clean water before use. The mistake isn’t in the method, it’s leaving the cup soaking for many hours “to be safe” or using a higher concentration than recommended.

Frequently asked questions about sterilizing a menstrual cup

If this is your first cup and you still have general questions about using it, start with our guide to choosing your first menstrual cup, and if you want to compare the different Sileu menstrual cup models before deciding, we have a full comparison. And if the daily cleaning process (not sterilizing) still raises questions, our guide on how to clean your menstrual cup explains it step by step.