How Long Can You Leave a Menstrual Cup In? Quick Answer
You can leave a Ruby Cup in for 8–12 hours at a time, depending on your flow. 12 hours is the maximum time between emptying and rinsing it, so on heavy-flow days you may need to empty it sooner.
- Overnight is fine as long as you empty and rinse your cup before bed and again when you wake up.
- 12 hours is a limit, not a target — empty your cup sooner if needed, especially on heavier-flow days.
- Tampons need changing more often: the FDA recommends changing them every 4 to 8 hours.
Are Menstrual Cups Safe?
Menstrual cups are safe when used correctly. There is a very small risk of infection if a menstrual cup is left in too long.
The Lancet, one of the most prestigious medical journals, published a review of all the research about menstrual cups and concluded that menstrual cups are an effective and safe alternative to other menstrual products.
Are reusable period cups approved by health organisations in the UK?
In the UK, menstrual cups are not classified as medical devices. This means they do not require approval or regulation by the Medicines and Healthcare products Regulatory Agency (MHRA), the NHS, or other health organisations.
Instead, menstrual cups are covered by the General Product Safety Regulations 2005, which require that only safe products are placed on the market. Manufacturers and distributors must:
-
Ensure products are safe for their normal or reasonably foreseeable use.
-
Provide consumers with clear safety information and instructions for proper use.
Many brands voluntarily follow international quality standards, such as those set by the International Organization for Standardization (ISO), to demonstrate quality and build consumer confidence. While this is not mandatory in the UK, it helps ensure the product is safe and reliable.
At Ruby Cup, we go beyond these requirements. Our cups undergo voluntary testing to guarantee high quality and safety:
-
All Ruby Cups are made from medical-grade silicone produced in strict accordance with European standards (UNI EN ISO 10993-1:2010).
-
Our silicone complies with EU regulations on volatile organic matter (VOM) in silicone products.
-
For our own quality assurance, we treat Ruby Cups as if they were a Class II medical device, performing tests for biocompatibility, cytotoxicity, irritation, and sensitisation.
The medical-grade silicone we use is resistant to bacteria and easy to sterilise. Silicone has a long history of use in medical devices and implants because it is safe, non-reactive, and unlikely to trigger allergic reactions, making it ideal for menstrual hygiene.
How Long Can You Wear a Menstrual Cup?
One of the greatest benefits of a menstrual cup is the number of hours it can be used, but how do you know how many hours to leave it in for?
Although cups have been around for many years, like many other period and menopause linked issues, there is a lack of data and studies about menstrual cups. Global standards on the material used and length of time cups can be left in are yet to be established.
At Ruby Cup, we take safety very seriously, we use a premium quality medical grade silicone for our cups and err on the side of caution by recommending that you wear your menstrual cup for no longer than 12 hours.
12 hours is the maximum recommended time between emptying and rinsing your Ruby Cup. Many period cup users need to empty their cup more frequently than this if they have a heavy flow or on heavier days of their cycle.
Related post: How to clean a menstrual cup in a public bathroom.
Menstrual Cup Wear Time at a Glance
The short answer: you can wear a Ruby Cup for up to 12 hours, and less on heavy days. Here is how that works in different situations.
| Situation | Wear time | What to know |
|---|---|---|
| Light to medium flow | Up to 12 hours | 12 hours is the maximum between emptying and rinsing, not a target. |
| Heavy flow | Less than 12 hours | Empty as often as you need to prevent leaks. The Ruby Cup Medium holds more. |
| Overnight | Up to 12 hours | Empty and rinse before bed and again when you wake up. |
| Longer than 12 hours | Not recommended | Bacteria can grow on a cup left in too long, which raises the risk of infection. |
| For comparison: tampons | 4 to 8 hours | Change each tampon every 4 to 8 hours, according to the FDA. |
Why Is There a Limit To How Long Can You Leave a Menstrual Cup In?
Bacteria can grow on a menstrual cup that is left in for too long, increasing the risk of infection. The same is true for tampons, the FDA recommends that users change each tampon every 4 to 8 hours.
Ruby Cups are made from 100% medical-grade silicone and unlike many tampons they are blissfully free from plastics, latex, toxins and bleaches.
How To Reduce The Risk Of Menstrual Cup Infection
You can reduce risk of infection by following these easy steps:
- Always wash your hands thoroughly with soap and water before handling your period cup
- Rinse your period cup with water before and after use.
- Do not leave your period cup in for longer than 12 hours before emptying and rinsing.
- Disinfect your period cup at end of cycle - either by boiling in a pan for 2-3 minutes or by using a Ruby Steriliser.
Can Menstrual Cups Cause TSS?
Toxic Shock Syndrome is a very rare but life-threatening condition where bacteria which usually live on the skin go deeper into the body. The risk of TSS associated with a menstrual cup is globally very low. Numbers vary between 0.8 and 3.4 of 100 000 people using menstrual cups compared to 6 to 12 people using high absorbency tampons in 1980.
TSS can be avoided by washing your hands thoroughly with soap and water before and after handling your cup, and emptying and rinsing your menstrual cup at least every 8-12h. Read more about TSS and how to avoid it here.
Can You Sleep With A Menstrual Cup In?
Yes. You can sleep with a menstrual cup in. A Ruby Cup can be worn overnight for up to 12 hours, so you don't need to wake up during the night just to empty it.
How to Use a Menstrual Cup Overnight
- Wash your hands with soap and water.
- Empty and rinse your cup just before bed, then reinsert it.
- Sleep as normal. Most people comfortably sleep 7 to 9 hours, which is well within the 12-hour limit.
- Empty and rinse your cup as soon as you wake up.
For example, if you insert your cup at 11pm, empty it by 11am at the latest. Many people will do it much earlier.
Tips for Heavier Nights
- If you have a heavy flow, you may need to empty your cup more often during the day so it starts the night as empty as possible.
- Choose the size that suits your flow. The Ruby Cup Medium holds more menstrual fluid. See our guide to finding your cup size.
- For extra protection, wear your cup together with period pants.
- If you are leaking, read why your menstrual cup might be leaking and how to fix it.
If You Sleep In or Forget to Empty Your Cup
If you realise you have gone past 12 hours, remove your cup, empty and rinse it. Don't skip this step just because nothing feels wrong. If you feel unwell afterwards, for example with a sudden high fever, dizziness or a rash, remove your cup and get medical help straight away. Read more in our guide to menstrual cups and toxic shock syndrome.
Does Size Affect How Long Can You Wear a Menstrual Cup?
At Ruby Cup we have two menstrual cup sizes – small and medium. There are two factors to consider when you’re working out which size Ruby Cup will work for you: the amount of blood you lose when you have your period (your menstrual flow) and the location of your cervix.
The Ruby Cup Medium can hold more menstrual fluid, making it a great choice if you have a heavy flow. It’s also a good fit if you have a high cervix. If you have a light flow and/or a low cervix, we recommend you choose the Ruby Cup Small.
Find out more about what size menstrual cup fits you best in our menstrual cup size chart.
Our 100% money-back guarantee not only gives you time to get used to using your new cup, but if you think you need to order a different size, we’ll exchange it for you – or give you your money back – with pleasure.
How Long Do Menstrual Cups Last?
Your Ruby Cup should last for ten years when properly cleaned and stored, however you should replace your cup if it gets any holes, cuts or is in bad condition.
You may notice slight discoloration over time, this is normal and will not affect the effectiveness or safety of the cup.
Related post: How to clean a menstrual cup
