The menstrual cup is a pretty amazing feat of engineering and design. If cups and vaginas weren’t so varied we would be out of a job! This article and video aims to explain how menstrual cup firmness works and why it matters when selecting and using your cup.
What does cup firmness even mean?
When we talk about the firmness of a menstrual cup we are talking about the amount of resistance the cup exerts when squeezed and squished. As you squish a cup with your hands it will either collapse easily without giving up a fight and bounce back with the same lazy amount of force, or the cup will give you more of a fight and when you release the cup it rebounds immediately and with a POP!
The cup that didn’t give up a fight is one we would consider “soft” and the cup that forcibly popped back open is one we would consider “firm.”
Menstrual cups have varying levels of firmness and this comes into play in multiple ways in how the cup works, leaks or doesn’t, is comfortable or isn’t, stays in place or doesn’t.
For our purposes we use a rating system from 1-5 where 1 is very soft and 5 is very firm. Cups rating a 2-3 are somewhere in the “average” category with 3 being what we consider “firm average” and 2 being “soft average.”
Silicone or TPE or Rubber
Silicone and TPE also have different properties, but it’s safe to say a silicone cup in your hands is a 2 and also a 2 in your vagina, while a TPE cup does actually soften with warmth so it may feel quite firm in your hands but while being worn may feel less firm.
Shore Scores vs PACII Firmness Scale
And while there are brands or websites that like to use a “shore score” which is basically the measurement of the silicone thickness using a durometer, this method of rating how firm or soft a cup is doesn’t work well. The thickness certainly plays a huge role in how firm a cup is, but the rim and shape are just as important. A cup with a soft body and low shore score can still feel and act like a firm cup if the rim itself is firm.
In order to quantify firmness in menstrual cups we reluctantly decided to devise our own firmness ratings. Using a 1-5 scale, with 1 being the softest, we hand “test” firmness of cups. Each cup is thoroughly squished and we compare cups to one another with The Diva Cup being the “center” point at a very solid “3” on our scale. As unscientific as our method of squishing and comparing cups is, it’s a better overall indicator of how the cup FEELS and is more accurate than a shore rating when it comes to how to cup acts on insertion and feels to the wearer. It’s not perfect and our scores are hotly debated by people who swear they think brand of cup X is firmer or softer than we say, and this is why we repeat that our scores are not definitive and firmness is subjective. It is, however, the best we can do and still better than a shore score.
Related: PACII Menstrual Cup Firmness Chart
On the topic of “Squish Testing”
While there are many people who will compare cup firmnesses by squeezing two cups together (a menstrual cup squish test) one stacked atop the other, this method is visually satisfying because it appears clear who is firmer and softer, but this also isn’t a perfect method. These squish test comparisons are usually done to compare two brands but the bottom cup will always collapse more than the top, plus it depends on the angle of your hands and so on. It’s useful in comparing but not as thorough as true hand to hand, side to side, comparison testing that we do to determine overall firmness.
Softer Cups (1-2): Pros and Cons
- More comfortable to wear- they don’t apply outward pressure than can make the user feel the presence or the cup, or in some cases, feel the urge to urinate or inability to urinate fully or partially.
- Softer cups don’t open as easily and may be more prone to leaks unless the user manually assists the cup to open at insertion.
- Can’t be pushed up higher into position from the base since it collapses.
- May slip for some wearers during physical activity or be “crushed” and leak.
Firmer Cups (4-5): Pros and Cons
- Less chance of leaking because the cup opens easier inside the wearer, better for new cup users.
- Stays in place against muscle movement so great for more active wearers
- Can apply more outward pressure against the urethra or bladder giving the wearer the feeling of having to urinate, or making urine exit slower or blocking urine.
- Can apply more pressure that affects bowel movements, making them more difficult to pass in some cases
- Pressure can also mean the cup is felt inside even if it’s not painful or uncomfortable, can be distracting.
Let’s meet in the middle with Average Cups (2-4)
To alleviate the cons and gain the benefits of each type of cup, soft or firm, we like to point users to cups somewhere in the middle. Average firmness cups in the 2-4 range are best for new users and in most cases, feel great without the cons.
If you try an average cup and find you have those cons then you probably want to swing a bit higher or lower on the scale. For example, if you still feel your cup during wear and have slight pressure, a softer cup may be more comfortable. Or if the cup slips down during activity, a firmer cup may be the solution. Firmness related issues are the biggest unknown when people switch to a cup because cups act unlike any other product in this way and it’s hard to tell, before ever trying a cup, what firmness level is going to feel best for you.
If you start with an average cup you will likely end up with a cup that works well, and feel pretty good.
This is why our menstrual cup quiz points users to cups in that range most often, with the Saalt Soft, Lena Sensitive, Sustain being popular results in the Average soft outcome, and the Lena, Saalt, and Lunette regular being popular in the Average Firm outcome. One tip for those who don’t know where to start is to choose the brand you try if it’s recommended through our quiz that has a Satisfaction Guarantee of some sort. These brands will often send you another cup size or firmness level to try if the first isn’t successful. Click the “compare your results” link in your quiz results to see which brands offer this, or browse brands on our Shop and Compare tool.
You’ve grown soft on me…
One more thing to mention about firmness- cups can soften over months or years of use, and/or from frequent boiling. A cup that started out working well that begins slipping down or maybe leaking, might be softer after many years of use.
Have something to add? Let us know in the comments!