A tampon is a small, cylinder-shaped product designed to absorb menstrual blood from inside the vaginal canal during your period. It sits internally, which makes it invisible under clothing and allows you to swim, exercise, and go about your day without a visible pad. Tampons are one of the most common menstrual products worldwide, and they come in different sizes to match the heaviness of your flow.
How a Tampon Works
A tampon is made of compressed cotton, rayon, or a blend of both. When you insert it into your vaginal canal, the fibers expand as they absorb menstrual fluid, forming a soft barrier that prevents blood from leaving your body until you remove the tampon. A string attached to the base hangs outside your body so you can pull it out when it’s time to change it.
The vaginal canal has a natural slight curve toward your back, so the tampon is angled in that direction during insertion. When it’s positioned correctly, you shouldn’t feel it at all. If it’s uncomfortable, it’s usually just not far enough in, and you can use a clean finger to nudge it into place. The tampon can’t get lost inside you because the cervix (the narrow opening to your uterus) blocks it from going any further.
Most tampons come with a plastic or cardboard applicator that helps guide the tampon into place. Some are sold without an applicator, meaning you use your finger to push the tampon in directly.
Choosing the Right Absorbency
Tampons are labeled by how much fluid they can hold, and these labels are standardized by the FDA so they mean the same thing across every brand:
- Light: absorbs 6 grams or less
- Regular: absorbs 6 to 9 grams
- Super: absorbs 9 to 12 grams
- Super plus: absorbs 12 to 15 grams
- Ultra: absorbs 15 to 18 grams
Your flow changes throughout your period, so many people use a higher absorbency on heavier days (usually the first two or three) and switch to a lighter tampon toward the end. The general rule is to use the lowest absorbency that handles your flow without leaking. If a tampon is still mostly white when you remove it after several hours, you can drop down a size. If it’s saturated in under two hours, go up one.
Swimming and Exercise
One of the main reasons people choose tampons over pads is for activities where an external product would be impractical. Tampons work well for swimming because they absorb menstrual fluid internally before it leaves your body. Water pressure in a pool or ocean can slow your flow slightly, but it doesn’t stop it, so you still need internal protection. Pads are not an option in water because they simply absorb the surrounding water and fall apart.
A tampon may soak up a small amount of pool or ocean water, so it’s a good idea to change it shortly after you get out. This also keeps the tampon from sitting in your body longer than necessary.
For other physical activities like running, yoga, or cycling, tampons stay in place and move with your body. Exercise during your period can actually help with cramps. Research on women with regular period pain found that 30 minutes of aerobic exercise three times a week significantly reduced the severity of cramps after about eight weeks.
How Long You Can Wear One
Change your tampon every four to eight hours. On heavier days, you’ll likely need to change closer to the four-hour mark. On lighter days, you can go longer, but don’t exceed eight hours even if the tampon isn’t fully saturated. Wearing one overnight is fine as long as you insert a fresh tampon right before bed and remove it as soon as you wake up, staying within that eight-hour window.
Always wash your hands before inserting a new tampon and after removing the old one. Used tampons go in the trash, not the toilet, since they can clog plumbing.
Toxic Shock Syndrome
Toxic shock syndrome (TSS) is the risk most commonly associated with tampon use. It’s a rare but serious bacterial infection that can develop when a tampon is left in too long or when a higher-absorbency tampon than needed creates conditions for bacterial growth. The incidence has dropped dramatically since the 1980s, falling from 6 to 12 cases per 100,000 women of menstruating age in 1980 to roughly 0.5 per 100,000 in later surveillance data.
TSS comes on suddenly. Symptoms include a high fever, chills, nausea or vomiting, diarrhea, dizziness or fainting, a rash that looks like a sunburn, and redness in the eyes or throat. In later stages, the skin on your palms or the soles of your feet may peel. If you develop these symptoms while wearing a tampon, remove it immediately and seek emergency medical care. TSS progresses fast and needs treatment quickly.
The most effective way to lower your risk is to use the lowest absorbency tampon that works for your flow and to change it within the recommended timeframe. Some people alternate between tampons and pads throughout the day as an extra precaution.
Materials and Shelf Life
Tampons sold in the U.S. are regulated as medical devices by the FDA. They’re made from cotton, rayon, or a cotton-rayon blend. The bleaching process used on these fibers is free from elemental chlorine, which prevents dangerous levels of dioxin (an environmental pollutant) from remaining in the product.
Unopened tampons are good for about five years. After that, the fibers can start to break down or develop mold, especially if stored somewhere humid like a bathroom cabinet. An expired tampon might cause itchiness, irritation, or increased vaginal discharge. If you notice any visible mold on the absorbent core or the tampon looks discolored, throw it away. Storing tampons in a cool, dry place helps them last until their expiration date.