Flex Reusable Menstrual Disc
Lower concern; silicone product with no known PFAS issues.
Flex Disc is made from medical-grade silicone, a material with lower inherent PFAS risk. Brand provides no PFAS statement, but silicone menstrual products have not been flagged in independent testing.
We flunk more products than we pass. This one earned its grade. How we grade
Material
medical-grade silicone
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What Flex Reusable Menstrual Disc is made of, ingredients and materials
The Flex Disc is manufactured from medical-grade silicone, a synthetic polymer that is inert at body temperature and does not degrade or leach chemicals during normal menstrual use. Medical-grade silicone undergoes rigorous biocompatibility testing (ISO 10993 standards) to ensure it does not release harmful substances into the bloodstream or mucous tissues. Unlike latex or lower-grade elastomers, this material does not contain natural rubber proteins, phthalates, or BPA. Silicone's chemical structure is stable and resistant to bacterial colonization, making it suitable for prolonged internal contact.
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Bacterial or fungal growth on surface
Silicone itself resists microbial colonization, but improper storage (in sealed wet environments) or infrequent washing may allow bacteria or mold to accumulate on the surface. This is a use-related hygiene issue, not a material defect, and is prevented by proper care.
Allergic reaction to silicone
Medical-grade silicone is biocompatible for most users, but individuals with documented silicone sensitivity (rare) may experience localized irritation. No widespread allergy reports specific to Flex discs are on record; sensitivity is typically tied to individual immune response rather than contamination.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Silicone degradation and leaching over time
Medical-grade silicone used in Flex discs is formulated to resist degradation during normal menstrual use. No reported cases of silicone breakdown or leaching from Flex or comparable medical-grade silicone discs have been documented in clinical literature or consumer complaints.
Fragrance allergens or additives in packaging or materials
Flex discs contain no added fragrances or dyes; the silicone is unfilled and unscented. The product does not include antimicrobial coatings, colorants, or accelerators that might trigger contact dermatitis.
Heavy metals
Medical-grade silicone must meet USP Class VI standards, which limit trace metals such as lead, cadmium, and arsenic. No heavy metal contamination has been reported in Flex discs or other FDA-cleared silicone menstrual devices.
Source, FDA ↗How is this PFAS grade calculated?
The brand's record and disclosure
Flex has published product safety documentation and material certifications on its website, including biocompatibility statements. The brand does not explicitly market PFAS-free status, but there are no public records of PFAS-related complaints or regulatory action against Flex menstrual discs. The product is FDA-cleared as a Class II medical device (510k pathway), which requires proof of substantial equivalence to existing menstrual cups and discs on the market. Flex's disclosure on materials and manufacturing is transparent compared to many period-care brands that provide minimal technical data.
How it compares in its category
Menstrual discs and cups in the reusable category typically use medical-grade silicone, latex, or thermoplastic elastomer (TPE). Silicone is the most commonly chosen material and carries no known contamination risks when sourced from reputable manufacturers. Flex's disc is comparable in material safety to brands like Lumma, Nixit, and Saalt; all use certified medical-grade silicone with similar biocompatibility profiles. The reusable disc category overall poses lower chemical exposure risk than disposable pads and tampons, which may contain bleach residues, dioxins from chlorination, or undisclosed fragrance allergens.
If you buy it
Wash the disc with unscented soap and warm water after each use; do not expose to prolonged high heat (dishwasher safe on low heat only, avoid boiling unless the manufacturer specifies it). Store in a breathable pouch or container to prevent mold growth; inspect the silicone annually for tears, discoloration, or sticky residue, which may indicate degradation. Replace the disc every 1-2 years if used regularly, or sooner if you notice tears, permanent discoloration, or odor that cleaning does not eliminate. Silicone can absorb fragrance and dyes over time, so avoid storing it near perfumed products or in direct sunlight for extended periods.
What is not known about PFAS in this product?
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Flex has made none
Formulations change between production runs, so check the current label. How we grade.
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