Period underwear, also called period pants or period panties, looks and feels like ordinary underwear but has an absorbent gusset built in. You wear it instead of a pad or liner, or together with a menstrual cup as a back-up. This guide explains how period underwear works, how much it holds, how to choose the right size and how to wash it so it lasts.
Quick answer: Period underwear is reusable underwear with an absorbent gusset that you wear instead of a pad or liner. Lunette Period Panties hold up to one cup or three tampons' worth of blood, so they work on their own on light to medium days, or as back-up with a menstrual cup on heavier ones. Machine wash at 40 °C and hang to dry.
How does period underwear work?
Period underwear works in layers. In Lunette Period Panties:
- The layer next to your skin is breathable organic cotton. It feels soft against your vulva and wicks moisture away quickly, so you feel dry.
- The inner layers are highly absorbent and hold the blood or discharge.
- The outer layer is laminated polyester, which stops anything leaking through to your clothes.
A high gusset and a wide waist panel give full coverage, front and back. The main fabric is velvety, stretchy lyocell with a little elastane for a close fit, and the fabrics are Öko-Tex certified. Lunette Period Panties are made ethically in the EU.
How much does period underwear hold?
Lunette Period Panties hold up to one cup or three tampons' worth of blood. In practice that means:
- On light to medium days, you can wear them on their own.
- On heavy days, wear them together with your Lunette menstrual cup for extra security.
- On spotting days and the days around your period, they're a comfortable alternative to a panty liner.
How long you can wear one pair depends on your flow. Change them when they start to feel damp or heavy, just as you would change a pad.
| Period underwear | Menstrual cup | Disposable pads | |
|---|---|---|---|
| Worn | Like ordinary underwear | Inside, below the cervix | Stuck inside your underwear |
| Best for | Light to medium days, spotting, back-up | Any flow, sport and swimming | Any flow |
| How long | Change when it feels damp or heavy | Up to 12 hours (8 in France, Germany and Australia) | Change every few hours |
| Reusable | Yes, machine wash at 40 °C | Yes, up to 10 years with care | No |
Who is period underwear for?
Period underwear suits almost everyone who has periods:
- People who want less waste. You wash and wear them again instead of throwing pads away.
- Menstrual cup users, as a back-up while learning or on heavy nights.
- Teens and first periods, because they're simple to use and don't need to be inserted.
- Light days and discharge. You can wear them every day of your cycle, including for discharge between periods. Read more about brown discharge before your period and light periods.
- Light bladder leaks. Lunette Period Panties can also be worn for light incontinence.
Period underwear with a menstrual cup
Period underwear and a menstrual cup work well together.
- While you're learning to use a cup, period underwear catches any leaks while you get the fold and the seal right. A cup that's sitting right doesn't leak, and most people find their technique within two or three periods. If you're still getting leaks, read why your menstrual cup might be leaking.
- On heavy days and nights, the cup collects most of your flow and the underwear is your back-up.
- On light days, many people switch to period underwear alone.
How to choose your period underwear size
Lunette Period Panties come in sizes XXS to 5XL, based on your hip measurement.
- Measure around the widest point of your hips, just above your seat.
- Measure snugly, in centimetres.
- Find your size on the size chart on the product page.
They're designed to fit snugly, because a close fit is what keeps the gusset in place and protects against leaks. If you're between sizes or unsure, choose one size bigger than your usual.
Prefer a different cut? Lunette Period Panties are also available as a thong.
How to wash period underwear
Washing period underwear properly keeps it absorbent and leak-proof for longer.
- Rinse after wearing (optional). Many people rinse their pants in cold water first, until the water runs clear. Cold water helps prevent stains.
- Machine wash at 40 °C. An occasional 60 °C wash is fine. Wash them with similar colours.
- Skip fabric softener. Softeners can coat the fibres and make the absorbent layers less effective.
- Hang them to dry. Don't put them in the tumble dryer: heat can affect the laminated layer that stops leaks.
Store them like the rest of your underwear once they're completely dry.
How many pairs of period underwear do you need?
It depends on how you plan to use them. If you wear period underwear on its own through your period, most people want enough pairs for one or two days, plus the time it takes to wash and dry them. If you mainly use a cup and wear period underwear as a back-up or on light days, two or three pairs are often enough.
Why choose period underwear?
- Comfort. They feel like normal underwear, with nothing to insert.
- Less waste. Wear, wash and wear again.
- Confidence. The laminated layer keeps everything in.
- Flexibility. On their own on light days, with your cup on heavy days.
Ready to try them? Find your size on the Lunette Period Panties page.
Period underwear: frequently asked questions
How does period underwear work?
Period underwear has an absorbent gusset built into the pants. Lunette Period Panties have a breathable organic cotton layer next to the skin, highly absorbent inner layers that hold the moisture, and a laminated outer layer that stops it leaking through.
How much blood does period underwear hold?
Lunette Period Panties hold up to one cup or three tampons' worth of blood. That covers light to medium flow on their own; on heavier days, wear them with your Lunette cup.
How do you wash period underwear?
Machine wash Lunette Period Panties at 40 °C; an occasional 60 °C wash is fine. Hang them to dry and skip the tumble dryer, because heat can affect the laminated layer that stops leaks.
Can I wear period underwear with a menstrual cup?
Yes. Many people wear period underwear as a back-up on heavy days or while they learn to use a cup, and on their own on light days.
