Ruby Cup · Menstrual Cups
Flex Menstrual Cup
Lower PFAS concern; menstrual cups are simple silicone bodies without typical high-risk coatings.
Ruby Cup Flex is made from medical-grade silicone, a material not inherently associated with PFAS contamination in reusable period care. Menstrual cups lack the water-repellent, nonstick, or stain-resistant coatings that commonly require PFAS.
Shop Ruby Cup 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
Ruby Cup Flex uses medical-grade silicone, a thermosetting elastomer that does not contain BPA, phthalates, or typical endocrine disruptors found in lower-grade plastics. Medical-grade silicone is inert at body temperature and resistant to degradation from menstrual fluid or routine cleaning. Unlike rigid plastics, silicone does not leach monomers or break down into microplastics under normal use conditions. The material's density and cross-linking prevent absorption of contaminants from surrounding environments.
The brand's record and disclosure
Ruby Cup (now part of the Flex Company portfolio) provides limited public chemical safety documentation or third-party certifications on their website. The brand does not publish detailed material safety data sheets or disclose manufacturing testing for heavy metals or residual contaminants. No recalls, safety complaints, or regulatory actions are on record for this product. Marketing emphasizes sustainability and reusability but does not highlight safety testing or independent verification.
How it compares in its category
Menstrual cups as a category present lower chemical exposure risk than disposable pads or tampons, which may contain bleach residues, dioxins, or undisclosed fragrance additives. Medical-grade silicone cups are broadly safer than plastic or rubber alternatives that may use plasticizers or lower-purity elastomers. Ruby Cup's silicone formulation is typical for established brands (Lunette, DivaCup, Saalt); no evidence suggests Ruby Cup uses inferior or contaminated silicone batches compared to competitors.
If you buy it
Rinse thoroughly with water before first use. Clean after each cycle with mild soap and warm water; do not boil if the cup has a printed logo or stem, as high heat may degrade adhesive or printing inks. Replace every 2 years or if you notice thinning, cracks, or persistent odor. Store in a breathable pouch or open container, never sealed in plastic bags; silicone can absorb odors and mold can grow in occlusive, moist environments. Avoid bleach, hydrogen peroxide, or silicone-based lubricants that may degrade the material.
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.”
Microplastic shedding from cup degradation
Medical-grade silicone does not fragment into microplastics under normal menstrual use or routine cleaning. Degradation would require extreme heat or aggressive chemical exposure not encountered in typical use.
Heavy metal contamination in silicone base or colorants
Ruby Cup does not publish heavy metal testing data. If colored inks or dyes are used on the cup surface, cadmium or lead in pigments is theoretically possible, though no incidents are documented for this brand or category.
Residual monomer or oligomer leaching
Medical-grade silicone undergoes post-curing to remove volatile monomers. Ruby Cup does not disclose curing protocols, but the category standard minimizes leaching risk; no reports of irritation or toxicity from established silicone cup brands.
Bacterial or mold contamination from improper storage
This is a use and maintenance risk, not a manufacturing hazard. Storing the cup in sealed plastic or damp containers can promote fungal or bacterial growth; proper air-drying and breathable storage prevent this.
Fragrance or fragrance allergen additives in cup or packaging
Ruby Cup Flex is unscented and marketing does not reference fragrance. The category typically avoids fragrance to minimize mucosal contact sensitization; no evidence of fragrance additives in this product.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 78% 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.