What Does the ‘R’ On Tampons Mean?

On September 2, 2019, a group of women took to Twitter with a challenge: Ask your boyfriend or partner what they think the little “R” marking on tampons means.

They were referring to the little letter, either “L,” “R,” or “S,” in a circle on the wrapper.

The results were comical, to say the least.

“My girlfriend left a tampon at my apartment and idk where the left one is,” joked Twitter user Evan J Worthen as he guessed that the “R” stands for “right.” On a more serious note, Worthen later told Bored Panda that “the gap in male knowledge of women’s health is huge but there are also a lot of women and girls who don’t receive adequate knowledge of their own bodies.”

Whether you’re one of those clueless boyfriends or a person who actually has to deal with periods first-hand, you may not know what those letters actually mean.

Put simply, those letters represent tampon absorbencies, meaning how much blood a tampon can hold in an eight-hour period without leaking. Understanding what these markings stand for — and how tampon absorbencies affect health — can help women have healthier, safer and more worry-free periods.

What Do the Letters on Tampons Mean?

Tampons are thin and compact wads of cotton that, when inserted into the vagina, staunch the flow of menstrual blood. Like all absorbent materials, they can only hold so much fluid at a time. The letters on tampons reflect these standard absorbencies: L means light, R means regular, and S means super.

There are federal standards that govern how much blood each category of tampon holds. Light tampons can hold up to six grams of fluid, regular tampons can hold between six and nine grams, and super tampons can hold between nine and 12. There are larger tampon sizes for people with extremely heavy flows, including super plus, which hold up to 15 grams of menstrual blood, and ultra absorbency, which hold between 15 and 18 grams.

Scientists test absorbencies in laboratories using a device called a “syngyna,” or synthetic vagina. These devices are meant to mimic the moistness and body temperature of a human vagina, but they use saline solutions rather than blood to test absorbency.

The exact meaning of the letters is ultimately less important than the precise fluid each tampon is able to hold. The important thing, according to Jennifer Conti, MD, MS, a professor at Stanford University’s School of Medicine and co-host of The V Word Podcast, is to determine your personal absorbency needs.

“The names are arbitrary, but the differentiation helps determine the right absorbency for you depending on where you are in your cycle,” Conti said.

Why Are Absorbency Ratings Important?

Knowing the right absorbency for your menstrual flow is important because using larger than necessary tampons, or leaving tampons in the vagina for too long, can be bad for your health.

Inappropriate tampon absorbency is associated with Toxic Shock Syndrome (TSS), a dangerous and potentially fatal infection. While tampons aren’t the only cause of TSS, they have historically been a major culprit of the disease in menstruating women.

There’s no need to panic about TSS risk. You just need to follow some basic guidelines.

Toxic Shock Syndrome (TSS)

In 1980, the Centers for Disease Control and Prevention (CDC) noticed an uptick in unusual cases of acute, sometimes fatal, infections among menstruating women. Symptoms included high fever, low blood pressure, a sunburn-like rash and damage to multiple organ systems. In the early 1980s, up to 5% of women who contracted this illness, which scientists dubbed Toxic Shock Syndrome (TSS), had died.

Scientists soon discovered a common thread in these infections: Many of the women who had TSS were using tampons, particularly with the brand Rely, a highly absorbent variety that mixed synthetics with the traditional cotton for longer use.

The mix of synthetic materials and long-term wear provided a perfect home for Staphylococcus aureus, a bacterium that normally lives in some people’s vaginas. While S. aureus is harmless when its population is controlled by natural microbiomes, high-absorbency tampons — particularly those that incorporate synthetics — provide a perfect “petri dish” for these bacteria to multiply.

Tampons aren’t the only objects that can cause TSS. Menstrual cups, which stay in the body for up to 12 hours at a time, can also provide the perfect conditions for harmful S. aureus to grow.

This is why choosing menstrual products with the right absorbency for your flow, changing tampons regularly, and alternating insertable products like tampons and menstrual cups with sanitary napkins is so important.

“The reason we don’t recommend using the biggest available tampon, even if it buys you more time before changing it, is because of the risk of toxic shock syndrome,” Conti said.

Vaginal Irritation and Discomfort

Tampons don’t just absorb menstrual blood, they also absorb natural discharge. This fluid regulates vaginal pH to keep a healthy balance and prevent the complications that arise when vaginal pH gets too acidic, like bacterial vaginosis.

During menstruation, vaginal pH often rises, and tampons can exacerbate these effects. This increase can lead to vaginal drying, and can also cause slight vaginal tearing or irritation.

Tampons can be physically uncomfortable for some users, and others may find them difficult to insert. These risks all increase with larger absorbencies, so some users may be more comfortable using tampon sizes with smaller absorbency.

How Can I Tell What Absorbency is Right for Me?

To minimize TSS and irritation risk, you should choose as low an absorbency as possible to match your flow.

“The right fit happens when your tampon lasts a couple of hours before needing to be changed,” Conti said. “If you’re soaking through Regular size tampons every hour, you might need to size up to a Super, and alternatively if your Super tampon is lasting 6 hours, you likely need to size down to a Regular.”

If you’re still worried, you can choose alternate period products or limit tampon use. Because menstrual cups are insertive, they still come with some TSS risk, though they do address other issues related to tampons, such as reducing waste. You can choose to forgo tampons altogether and choose non-insertive menstrual products, like pads, sanitary napkins, or period underpants, to limit TSS risk.

Using non-insertive methods of menstrual protection can also help eliminate vaginal discomfort and dryness associated with tampons. You should also avoid products that use synthetic materials, and scented tampons, which can also cause irritation and throw off vaginal pH.

How Worried Should I Be?

TSS risk might sound scary, but it’s not as prevalent as you may think. To put it into perspective, only 1 in 100,000 people who menstruate will contract the disease.

So, as long as you’re matching your flow with the correct absorbency, changing tampons regularly, and avoiding products with synthetics, you have nothing to fear from tampons. Have a happy — as much as possible, anyway — period!