The materials used to make menstrual cups are of great importance. We have therefore summarised our knowledge on this subject to enable you to make an informed choice.
What are menstrual cups made of?
As far as we know, there are 3 materials for the manufacture of menstrual cups:
- Most of them are made of medical silicone: we will develop this material further below as there is a lot to say about it
- Some menstrual cups are made of medical TPE (TPE = thermoplastic elastomer). This is a petroleum-based material that has been tested for biocompatibility and complies with high medical standards (it is used for catheters, medical membranes, etc.). The major drawback of menstrual cups is that they are not very resistant to high temperatures: most TPEs are guaranteed to be stable below 125°C. However, when you boil your menstrual cup in water, it is already at 100°C, it must not remain in contact with the bottom of the pan, otherwise it will lose its physical and chemical properties.
- Finally, we know of a natural rubber cup sold in the USA. However, rubber is still highly allergenic.
But let's develop the most common material: medical silicone.
What is silicone?
Silicon is a polymer composed mainly of silicon and oxygen. Silicon is the second most abundant chemical element on Earth (just after oxygen), accounting for 1/4 of its mass.
Silicone is therefore not a plastic in the common sense of the word, as it is not produced by the petrochemical industry.
Silicon does not contain oil and is closer to glass in that its raw material is silicon, which is found mainly in sand.
Silicone has a multitude of applications: there is conventional silicone, food grade silicone, medical silicone. Each has its own set of regulatory requirements, and obviously, for menstrual cups, medical silicone is used.
It also has a wide variety of consistencies: liquid, gel, gum, hard... We will come back to this.
The different types of medical silicones
For our purposes, medical silicone is used in wound care gels, orthopaedic products, disposable syringe seals, medical tubing, anaesthetic masks... and menstrual cups!
But if all these applications are health-related, they do not require the same level of purity. There are internal and external uses, single use and long term use...
Therefore, all silicone menstrual cups are made from medical silicone. To obtain the necessary consistency for the manufacture of a menstrual cup, it is necessary to add a catalyst to the silicone, which will harden the material to the desired "shore" (the hardness or flexibility of a silicone is measured by a number of shore). And this catalyst is very important...
Peroxide-catalysed silicone.
It is the 1st generation of medical silicones.
Peroxide is a chemical active composed essentially of oxygen and carbon.
It is a very powerful oxidant (it is what turns hair blonde, for example), naturally unstable (especially under the effect of heat), and is known to be harmful to the body in certain quantities and for certain periods of time.
The reaction to peroxide leaves an acidic residue on the surface which must absolutely be cured by a cooking process after the menstrual cup has been moulded
This silicone is cheap, but it can transfer volatile organic compounds, especially when heated. It has a higher surface tackiness, which can lead to it becoming dirty more quickly. It is mainly used for single-use products.
And unfortunately, it is also used in a large number of menstrual cups. Because it remains "medical silicone", the "medical silicone" argument reassures on the box. And as the regulations are light on the manufacture of menstrual cups, there is nothing legally preventing the use of this type of silicone. But now you know.
Platinum-catalyzed silicone.
Platinum is a rare and valuable (and expensive) natural chemical element that is particularly stable and heat resistant.
It is mixed in minute proportions with the silicone to cure it, and no by-products are released during the reaction.
Platinum-catalysed silicones therefore have a higher level of purity and do not transfer residues.
Platinum medical silicone is considerably more expensive than its cousin peroxide medical silicone, but it is completely non-toxic, stable, odourless, non-stick, hydrophobic and sterilisable: it has the best biocompatibility. It is also bacteriostatic, meaning that bacteria do not grow on its surface.
This is obviously the one we chose to make La Cup Luneale.
What about antimicrobial silicone?
You may have heard of antimicrobial silicone menstrual cups. And you may think it's an asset to limit microbes in the vagina.
In fact, we looked into the matter when choosing the ideal material for La Cup Luneale: we wanted the best.
But microbes is actually a common name for a set of 3 things: fungi, viruses and bacteria.
Antimicrobial silicone is actually a silicone that has been treated with silver ions after being moulded. Silver ions are nanoparticles, which, depending on their size, can pass through the skin barrier and whose effects on both health and the environment are still too unclear. The French National Agency for Food, Environmental and Occupational Health Safety (ANSES) issued an opinion on 5 March 2015 in which it"emphasises the research efforts on the potential health and environmental effects of silver nanoparticles, but notes that these remain insufficient to allow an assessment of the health risks". The Agency therefore recommends limiting the marketing of products to applications where their usefulness has been clearly demonstrated.
In short, we don't know much about it yet. What we do know is that the vaginal flora is made up of bacteria. GOOD bacteria, which are necessary for intimate balance and protect against most infections. So weighing up the potential benefits and risks, we have ruled out this type of silicone for our cups, as the usefulness of silver treatment has not been proven for this application. Especially since platinum silicone is bacteriostatic.
The special case of silicone prostheses.
The breast prostheses consist of a medical silicone shell, which is filled with a liquid medical silicone gel. In the vast majority of cases, everything is OK and very controlled.
The scandal that took place several years ago was due to an unscrupulous company of swindlers who filled medical silicone envelopes with industrial silicone gel (which is used to lubricate machine tools etc.), which is obviously much cheaper.
And when some of the envelopes were punctured, industrial gel leaked into the bodies of the victims, causing severe damage.
We hope that this information has enlightened you, and that you will be wary of cheap cups. It is better to invest a little more, but be completely confident about the quality of the material.
Asian manufacturers regularly offer to make the Luneale Cup for us. For an absolutely crazy price, which does not even correspond to the price of the raw material we have chosen. Of course, we don't follow up on this, because we believe in the importance of the made in France and quality. We will never make concessions on health.
Feel free to ask us your questions in comments!
