A menstrual cup is a small, flexible, funnel-shaped device that you insert into your vagina during your period to collect menstrual fluid. Unlike tampons and pads, which absorb blood, a cup catches and holds it. Most cups are reusable, lasting several years before needing replacement, which makes them significantly cheaper and less wasteful than disposable products over time.
How a Menstrual Cup Works
You fold the cup and insert it into the vaginal canal, where it opens up and forms a light vacuum seal against the vaginal walls. That seal prevents leaks and keeps the cup in place while you move, exercise, or sleep. When it’s time to empty, you pinch the base to release the seal, pull it out, pour the contents into the toilet, rinse it, and reinsert.
The capacity is one of the biggest practical differences between cups and tampons. A menstrual cup holds between 30 and 60 milliliters of fluid depending on the brand and size. A regular tampon holds about 5 milliliters, and a super tampon holds around 10. That means even a small cup collects several times more than a tampon, so most people can go longer between changes. Many manufacturers recommend emptying every 8 to 12 hours, though heavier flow days may require more frequent emptying.
What They’re Made Of
Most modern menstrual cups are made from medical-grade silicone, a material that’s biocompatible, meaning it won’t trigger a toxic or immune response in the body. The first modern cup, introduced in 2002 by the Moon Cup brand, used this type of silicone and it remains the most common material today.
Some people are allergic to silicone, though, so manufacturers also offer cups made from thermoplastic elastomer (TPE), which is latex-free. Older designs used natural rubber, but that material contains latex and causes allergic reactions in more users. If you have a known sensitivity to silicone or latex, the material will likely be the deciding factor in which cup you choose.
Finding the Right Size
Menstrual cups come in multiple sizes, and getting the right fit matters for both comfort and leak prevention. Most brands offer at least two sizes based on a few key factors: age, birth history, cervix height, and flow volume.
The smaller size is typically designed for people under 30 who haven’t had a vaginal delivery or full-term pregnancy. The larger size is for people over 30 or those who have given birth, because pregnancy and age can relax the pelvic floor muscles, making a slightly wider cup a better fit. That said, regular exercise can tighten pelvic floor muscles, so an active person over 30 may still do well with a smaller size.
Cervix height also plays a role. Your cervix position is essentially the length of your vaginal canal, and it can shift throughout your cycle. To check, insert a clean finger: if you reach your cervix at the first knuckle, it’s low; if your finger goes all the way in, it’s high. A low cervix calls for a shorter cup, while a high cervix can accommodate a longer one. Some brands, like MeLuna, offer shorter cups specifically designed for low cervixes, and others like Intimina make cups for higher cervixes or heavier flow.
Cleaning and Care
During your period, a simple rinse with water (and mild, unscented soap if available) between insertions is enough. At the end of each cycle, you’ll want to sterilize the cup by boiling it in water for a few minutes, up to 10 minutes maximum. Some brands sell microwave-safe sterilizing containers that let you boil the cup in 3 to 4 minutes without a stovetop.
Store the cup in a breathable cotton bag between cycles. Avoid airtight containers, which can trap moisture and encourage bacterial growth.
Safety and TSS Risk
Menstrual cups carry a low but real risk of toxic shock syndrome (TSS), the same rare bacterial infection associated with tampons. Any device left in the vagina for too long can create an environment where bacteria grow and release toxins into the bloodstream. The risk is lower than with highly absorbent tampons because cups collect fluid rather than absorbing it, but it’s not zero. Emptying your cup within the recommended timeframe and washing your hands before insertion are the most effective ways to reduce this risk.
Menstrual Cups and IUDs
If you use an IUD for birth control, this is worth paying attention to. A clinical trial published in the journal Contraception found that menstrual cup users had roughly three times the odds of IUD expulsion over 36 months compared to non-cup users, at least with certain smaller IUD models. The research team actually stopped recommending cup use partway through the study after observing the pattern. Cup users also experienced a higher rate of accidentally pulling their IUD out during cup removal.
The risk appears to vary by IUD type and may not apply equally to all models. But if you have an IUD, it’s worth discussing cup use with your provider, and always break the suction seal before pulling the cup out rather than tugging on it directly.
Cost and Environmental Impact
A single menstrual cup costs between $20 and $40 and lasts for several years. Over a full reproductive lifetime of roughly 40 years, the total cost of cups runs somewhere between $180 and $430, depending on how often you replace them. Compare that to buying pads or tampons every month for decades, and the savings are substantial.
The environmental case is similarly straightforward. A person who menstruates uses thousands of disposable products over their lifetime, each one containing plastic that takes centuries to break down in landfills. A reusable cup replaces all of them. For people motivated by either the financial or environmental angle, this is often the primary reason they switch.
The Learning Curve
Most people who try a menstrual cup for the first time find that insertion and removal take some practice. The cup needs to be folded for insertion (there are several folding techniques), and it can take a few cycles to figure out which fold works best, how to position the cup, and how to break the seal cleanly during removal. Leaks during the first cycle or two are common and don’t necessarily mean the cup is the wrong size.
Wearing a backup panty liner while you’re learning can take the pressure off. Most users report that by their second or third cycle, the process feels routine and takes no more time than using a tampon.