Period Products Explained: Pads, Tampons, Cups, Discs and Period Underwear

Any of them is a fine place to start, and that is the NHS's position rather than this page's. Its advice for someone whose periods have just started names tampons, menstrual cups, disposable or reusable pads and period underwear as safe and suitable — four kinds, no order, no age you have to reach first. The one property anybody has actually measured is how much each one holds. A 2023 review in Obstetrics & Gynecology estimates a fully saturated super pad at about 5ml and a nighttime pad at up to 15ml, puts menstrual cup basins at 8ml to 37ml measured to the suction-release holes, and menstrual disc basins at 30ml to 79ml. The NHS says a whole period is about 20 to 90ml, roughly 1 to 5 tablespoons. Those two facts together are enough to do your own arithmetic, and they are very nearly everything anyone has counted.

This page is for someone deciding what to put in a bag for the first time, or for a parent doing it with her. It compares kinds of product, never brands, and only on things that have been measured.

The five, described the way the NHS describes them

Pads are strips of padding with a sticky side that you attach to your underwear. They come in many sizes, so you can pick one to suit how heavy or light your period is. Pantyliners are the NHS's name for a smaller, thinner pad for days when a period is very light. Reusable washable pads exist too.

Tampons are small tubes of cotton wool that you insert into your vagina to soak up the blood, and they come in two types: with an applicator and without. The NHS also settles the rumour in one line — it is not possible for a tampon to get lost inside you, because your vagina holds it firmly in place. The step-by-step version, and the safety part told straight, is in how to use a tampon.

Menstrual cups collect the blood rather than absorb it, and unlike tampons and most pads they can be washed and used again. Period underwear are pants made from absorbent fabric that soak up blood in the same way a pad does, and they are made to be washed and reused.

That is four. The fifth, the menstrual disc, is the odd one out here: the only thing quoted about it on this page is the basin measurement from that 2023 review, because the NHS's list of what is safe and suitable for someone who has just started does not name it. That is not a warning — it means this page has one number and no description it is willing to stand on, and it would rather say so than fill the gap in.

Capacity is the one thing anybody has counted

Set those numbers next to the NHS's 20 to 90ml for an entire period and something obvious falls out: a period is not very much liquid, and each of these products is built for a fraction of it at a time. So "how many will I need" is a number you work out from your own days rather than one anybody can hand you.

Two cautions about the numbers, though. The 20 to 90ml is a whole period and it does not arrive in equal instalments — the NHS says the blood is red when a period is at its heaviest and may be pink or brown on lighter days, which is the same thing said another way. And a stated capacity is a ceiling rather than a schedule: a cup basin that holds 37ml to the suction-release holes tells you what the object can contain, not how long it may stay in. That is a different question with a different answer, two sections down.

What nobody has measured

This is the part other pages fill with confidence. Comfort has not been measured. Ease of use has not been measured. Which product is "best for beginners" has not been measured, by anyone, for anybody. The phrase is an opinion, not a finding, and the NHS's own line is simply that tampons, cups, disposable or reusable pads and period underwear are all safe and suitable if you have just started.

Period underwear deserves a sentence of its own here, because the gap is unusually stark. The 2023 review states plainly that no regulations exist regarding period underwear content or capacity. So a pair advertised as holding some number of tampons' worth is making a claim nobody is checking. What that means in practice, and what the one randomised trial found, is in period underwear, honestly.

One trial has put figures on the reusables. A 2025 randomised study in BMJ Sexual & Reproductive Health followed 20 adults with heavy menstrual bleeding across two cycles: participants changed disposable products a mean of 5.5 times a day, menstrual cups 3.3 times and period underwear 3.5 times, and the underwear held 22 plus or minus 18g of menstrual fluid against 48 plus or minus 30g with disposables. Its authors are careful about their own work — the sample size was chosen for feasibility because no earlier study existed to power it, and eight of the ten cup users had never used a cup before. Twenty people is twenty people, and it is still more measurement than most of this subject has.

Cost is unmeasured here too, because it depends on how much you bleed and what you buy, and nothing on this site quotes shop prices. That the reusable products can be washed and used again is the only structural fact about it anybody here can state — how much does a period cost takes it as far as the evidence goes and stops.

How long can you wear one? The box knows and this page does not

This is the question that gets answered most confidently online and it has no citable number here. What the NHS publishes is a rule rather than a figure: follow the instructions when using tampons and menstrual cups, and do not leave them in longer than needed or recommended. The leaflet in the packet is what "recommended" refers to, and it is specific to the product you actually bought.

So the instruction is the dull one: read the leaflet once and photograph it. A page that hands you a number instead has substituted its own guess for the manufacturer's testing, and you would have no way of knowing which product it had in mind.

The reason the rule exists at all is toxic shock syndrome, which the NHS describes as rare but life-threatening and says can happen when using a tampon or a menstrual cup. Both halves of that sentence are true at once, and the numbers that make sense of it — including a measured rate from population surveillance — are set out in how to use a tampon rather than repeated here.

What is known about cups, with the sample sizes attached

Cups have had more research than the rest of this list put together, which still is not much. A 2019 systematic review and meta-analysis in The Lancet Public Health gathered 43 eligible studies with 3319 participants — and notes that only three of those studies were of moderate-to-high quality, which is the number to keep in mind while reading the rest.

What it found: in the four studies that compared them directly, leakage with a cup was similar to or lower than with disposable pads or tampons. A pooled 73% of participants, with a confidence interval running from 59% to 84%, said they wished to carry on using one. Across the entire review the reported adverse events were five women with severe pain or vaginal wounds, six reports of allergies or rashes, nine urinary tract complaints, five cases of toxic shock syndrome and 13 dislodgements of an intrauterine device.

Those last figures are counts from a whole body of research rather than rates you can apply to yourself, and they are printed for the same reason the 73% is: a page that shows only the encouraging half of a review has edited it. The longer version is in menstrual cups, honestly.

When the product is telling you something worth an appointment

How fast you go through anything is information, and the NHS treats it as such. Its signs of heavy periods include needing to change a pad or tampon every 1 to 2 hours, needing to empty a menstrual cup more often than is recommended, needing to use 2 types of period product together, periods lasting more than 7 days, passing blood clots larger than about 2.5cm, bleeding through to your clothes or bedding, and avoiding daily activities because of your periods. It also says many women have heavy periods and they may be normal for you — both sentences are the NHS's, and they belong together.

There is a wrinkle the 2025 trial points at directly. Its authors conclude that the frequency of changing or emptying underwear and cups is not equivalent to the frequency of changing pads or tampons, and that reusable products may therefore result in missed diagnoses of heavy menstrual bleeding. In plain terms: the NHS's "every 1 to 2 hours" test was written around a disposable product, and if you have switched, the test is quieter than it used to be. Worth saying out loud at an appointment. And leaking through is a signal rather than an embarrassment — period leaks deals with the practical and the emotional half of that.

Starting, in about five minutes

Pick one thing and put it in a bag. The first period kit checklist lists what goes in and nothing else, and if you are ever caught out at school the NHS's own advice is to ask a teacher or the school nurse — an ordinary request that people are used to.

Then write the dates down, because every useful number about your own periods is built from them. The printable period tracker is one sheet for that and stores nothing anywhere, and the printable symptom tracker has room for how many products you got through on your heaviest day — the number that turns "it feels like a lot" into something a doctor can work with.

Talking to somebody first is the NHS's advice rather than an add-on: it suggests talking to your parent or another adult you trust about what to expect before it happens. Whoever is easiest.