Flex · Menstrual Cups
Flex Reusable Menstrual Disc
Lower-concern choice; silicone is not a PFAS vector, but brand offers no transparency.
Flex Menstrual Discs are made from medical-grade silicone, which does not inherently require PFAS coatings or treatments. The brand does not publicly disclose PFAS practices or hold third-party certifications on this topic.
Shop Flex on Amazon →Material
medical-grade silicone
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Category baseline
period care is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
The full breakdown
What it's made of and why it matters
Flex Disc is constructed from medical-grade silicone, a synthetic polymer chosen for menstrual products because it resists degradation, does not leach estrogen-mimicking chemicals like BPA, and tolerates repeated sterilization. Medical-grade silicone has a higher purity standard than consumer-grade silicone and is inert at body temperature. The disc design (flat, crescent-shaped) differs from traditional cups but uses the same base material, eliminating material-specific hazard concerns that apply to latex or thermoplastic elastomers.
The brand's record and disclosure
Flex has not published ingredient certifications, manufacturing standards, or third-party testing results on their website or marketing materials. The company does not disclose PFAS testing data despite PFAS being found in some medical-grade silicone sourced from certain suppliers. No recalls, litigation, or formal safety complaints against Flex Disc have been documented in FDA or CPSC records. The brand's silence on manufacturing transparency and PFAS testing is notably less rigorous than competitors like Saalt or Lunette, which provide material certifications.
How it compares in its category
Menstrual discs and cups made from medical-grade silicone occupy the safest tier of reusable menstrual products, with no documented cases of toxic leaching in clinical or consumer data. Flex Disc sits midfield on transparency: it avoids the chemical concerns of latex or polyurethane alternatives but lags peer brands in certifications (e.g., ISO 10993 biocompatibility). Plastic applicators or storage cases sometimes introduce BPA or phthalate concerns; Flex's packaging includes minimal single-use plastic, reducing this secondary exposure.
If you buy it
Rinse with cool water after each cycle and store dry in a breathable pouch; avoid prolonged contact with heat above 65 degrees Celsius or bleach, which can degrade silicone elasticity over years. Replace every 2 years if the disc loses flexibility or develops visible wear. Do not use during pregnancy or with IUDs without consulting a gynecologist. Clean before first use and after heavy menstrual flow; silicone does not harbor bacterial growth as readily as porous materials, but neglected discs can develop odor.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Silicone degradation and leachates
Medical-grade silicone used in Flex Disc is stable under normal use conditions. No published studies document leaching of oligomers or other degradation products from silicone menstrual discs at body temperature or with common household cleaners.
Bacterial or fungal contamination
While silicone itself resists microbial biofilm better than latex, improper storage (damp conditions, airtight containers) or infrequent cleaning can allow odor-causing bacteria or yeast to proliferate; this is a use-and-care issue, not a material defect.
PFAS in manufacturing or coatings
Some medical-grade silicone suppliers may use PFAS in processing or as mold-release agents. Flex has not disclosed testing or supplier vetting for PFAS. Given the brand's silence and the known presence of PFAS in some silicone products, low-level PFAS exposure cannot be ruled out, though it remains unlikely to exceed regulatory limits.
Allergic reaction to silicone or additives
IgE-mediated silicone allergy is extremely rare in clinical literature. Flex Disc is not known to cause contact dermatitis or systemic allergic responses; however, the brand does not disclose colorants or curing additives that might trigger sensitive individuals.
Loss of elasticity and structural failure
Users report occasional cracking or loss of flexibility after 1-3 years of use, particularly with heat exposure or aggressive cleaning. This is a durability concern rather than a chemical safety hazard but can lead to discomfort or leakage if the disc becomes rigid.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Menstrual Cups
Aisle
DIVA Cup Model 2
Medical-grade silicone (body); no Teflon-type coating or Teflon-family coating coatings
Lower-concern menstrual cup; silicone construction and PFAS-free commitment make it a reasonable choice.
✓Verified PFAS-free by a third party
Ruby Cup
Steriliser
Stainless steel heating chamber with silicone/plastic components
Lower-concern menstrual cup sterilizer; stainless core typical for appliances, but silicone/plastic parts unspecified, contact brand for material detail.
⚠Risky category by default
Ruby Cup
Steriliser Purple
stainless steel steriliser/heating element
Lower PFAS concern; no high-risk coatings typical of this product category.
⚠Risky category by default
More menstrual cups grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.