The adoption of menstrual cups has grown significantly, driven by a desire for more sustainable and cost-effective alternatives to traditional period products. These reusable cups are typically made from either medical-grade silicone or Thermoplastic Elastomer (TPE). As more people consider making the switch, a central question arises about the safety and suitability of TPE for internal use. This material must withstand the body’s internal environment while remaining non-toxic and durable through repeated use and sterilization. Understanding TPE and how it compares to silicone is necessary for making an informed choice about menstrual cup material.
Understanding Thermoplastic Elastomers (TPE)
Thermoplastic Elastomer is not a single material but a broad class of copolymers that combine the processing ease of plastic with the functional properties of rubber. This unique duality means the material can be melted, molded, and reformed like a thermoplastic, while still maintaining the elasticity and flexibility of a thermoset rubber. TPE is often a physical mixture of polymers, typically a plastic and a rubber component, which gives it this hybrid functionality.
Manufacturers favor TPE for medical and consumer goods due to its efficiency in production. It can be processed using high-volume methods such as injection molding, which is often more cost-effective and requires less energy than manufacturing with silicone. TPE is melt-processable and can be re-purposed or recycled at the end of its life. The ability to formulate TPE with a wide range of hardness levels and colors allows for significant design flexibility.
TPE’s Health and Regulatory Safety Profile
TPE is generally considered safe for use in menstrual cups, provided the product utilizes a medical-grade formulation. These medical-grade compounds are specifically engineered to be biocompatible, meaning they can come into contact with human tissue and bodily fluids without causing adverse reactions. Reputable manufacturers ensure their TPE is free from known harmful substances, including latex, phthalates, and Bisphenol A (BPA).
For a TPE menstrual cup to be legally sold in the United States, it must be regulated as a Class II medical device and must achieve clearance from the Food and Drug Administration (FDA) through the 510(k) pathway. This regulatory clearance requires manufacturers to demonstrate that the material is substantially equivalent in safety and performance to an already legally marketed device. The material itself is often tested against international standards such as ISO 10993, which evaluates biocompatibility through tests for cytotoxicity, irritation, and systemic toxicity.
A significant safety advantage of TPE is its low potential for allergenicity, as it does not contain the latex proteins that can trigger allergic reactions in some individuals. Concerns about the leaching of chemicals are mitigated by the material’s inherent design, which aims for a high degree of purity and a low level of extractable compounds. Some research suggests that TPE cups may exhibit lower levels of Staphylococcus aureus colonization and toxin production compared to silicone cups. However, this does not eliminate the need for proper hygiene and adherence to the recommended wear time.
TPE Versus Medical-Grade Silicone: A Comparative Look
TPE and medical-grade silicone offer distinct user experiences due to their inherent material differences, despite both being safe options. TPE cups often feel softer or more “rubbery” to the touch, and they become slightly more pliable and conforming when warmed by body temperature after insertion. In contrast, silicone typically maintains a higher compressive strength, meaning it retains its original shape more rigidly, which some users prefer for easier insertion and reliable opening inside the body.
Durability and longevity represent a primary difference between the two materials. Medical-grade silicone cups are widely known for their extended lifespan, often recommended for use up to 10 years with proper care. TPE generally has a shorter recommended lifespan, typically ranging from three to five years. TPE also has a lower temperature resistance than silicone, which requires users to exercise greater care during the sterilization process.
Regarding maintenance, TPE can be more susceptible to staining and absorbing odors compared to silicone, which is generally more non-reactive. TPE also has a higher compression strength, meaning that over years of use, a TPE cup may be more likely to lose some of its original firmness or shape. Silicone is highly resistant to permanent deformation. This difference in material behavior can be a deciding factor for users prioritizing either long-term shape retention or a softer, more conforming feel.
Caring for and Maximizing the Lifespan of TPE Cups
Proper maintenance of a TPE cup is essential for maximizing its lifespan and ensuring continued hygienic use. TPE cups must be sterilized between cycles, typically by boiling, but users must be mindful of the material’s lower heat resistance. Boiling should be done in a dedicated pot for five to seven minutes, while ensuring the cup does not touch the hot metal to prevent scorching or melting.
During the cycle, the cup should be cleaned after each removal using clean water and a mild, unscented, and water-based soap. Harsh chemicals or oil-based cleansers should be avoided as they can degrade the material. For storage between cycles, a breathable fabric pouch is necessary to allow the material to air dry completely and prevent the growth of mold or bacteria. TPE should never be stored in an airtight container or exposed to direct sunlight, which can accelerate material breakdown.
Users should regularly inspect their TPE cup for signs of degradation that necessitate replacement, regardless of the cup’s age. Indicators that the cup’s integrity is compromised signal that it is time to retire the product. These signs include:
- A sticky or tacky feeling.
- A chalky or flaky surface texture.
- Visible cracks or micro-tears.
- A persistent odor that cannot be removed after thorough cleaning.
- A significant change in the cup’s color or shape.