Modibodi Basic Mid-Rise Brief Black
Waterproof period underwear; PFAS risk unknown, brand silent on treatment.
Modibodi's leak-proof brief likely uses a waterproof barrier coating to contain fluids, but the brand does not disclose whether PFAS-based water-repellent coating treatments were applied. No third-party testing or PFAS claims found.
The safe swap
Lola
The Lola High Waist Period Underwear
100/100 safety
Same rubric that flunked this product. The swap earned Excellent.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Organic cotton with waterproof leak-proof lining
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Waterproof / stain-resistant treatment
water-repellent coating treatments have historically used PFAS.
Category baseline
period care is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
PFAS
The polymer or coating layer is not disclosed; it may contain acrylate-based, polyurethane, or other synthetic chemicals that could leach into sensitive skin contact zones. Without brand transparency or testing, residual monomers or plasticizers cannot be ruled out.
Source: ATSDR ↗Microorganism growth if improperly dried
The waterproof barrier can trap moisture if the product is stored damp or laundered in high-heat dryers. This creates a microenvironment for bacterial or fungal growth on a product in direct contact with mucous membranes and open skin.
Coating degradation over repeated washing
Polymer or laminate waterproof linings degrade with age and heat exposure. As the coating fails, small particles or leachates may be released, and effectiveness diminishes, but safety data on coating breakdown byproducts is not published by the brand.
Contact dermatitis or skin irritation
Synthetic lining chemicals or undisclosed finish residues on organic cotton may trigger allergic contact dermatitis, particularly in individuals with sensitive skin or vulvovaginal sensitivity. No ingredient list for the waterproof layer is available to screen for known allergens.
What’s reassuring
Dye or finish residues on organic cotton
Organic cotton eliminates pesticide risk but does not guarantee absence of azo dyes or formaldehyde resins used in printing or dyeing. Modibodi does not publish dye safety standards or ISO 14001 certification for this product line.
The full breakdown
What it's made of and why it matters
Modibodi Basic briefs use organic cotton as the primary fabric, which eliminates pesticide residues from conventional cotton but does not guarantee safety of the waterproof lining layer. The leak-proof barrier is the critical component and its chemical composition (likely a polymer coating or laminate) is not disclosed by the brand. Waterproofing in period underwear typically relies on synthetic treatments, and the specific chemistry here is opaque, making independent assessment of non-PFAS chemical leaching difficult.
The brand's record and disclosure
Modibodi is silent on PFAS treatment and provides no published testing or third-party certification for chemical content in their waterproof layers. The brand does not disclose whether their lining uses PFC-free alternatives, traditional Teflon-type coating-based coatings, or other polymer barriers. No major recalls or safety controversies are on public record for this product line, but the lack of transparency on the lining chemistry is a red flag for informed purchasing.
How it compares in its category
Period underwear without disclosed waterproofing chemistry sits in a murky middle ground. Brands like Aisle and Knix have published commitments to PFAS-free materials and third-party testing; Modibodi does not. Versus disposable pads or tampons, reusable period underwear reduces plastic waste but shifts chemical risk to the durable coating. Organic cotton construction is a relative plus, but the barrier layer is where hazard concentration typically occurs.
If you buy it
Wash in cool water and dry flat; heat may accelerate degradation of the waterproof lining and increase leaching. Inspect the lining annually for cracking, peeling, or odor changes; replace if degradation is visible. Avoid prolonged storage in sealed plastic bags, as trapped moisture can promote microbial growth and chemical off-gassing. Consider requesting the brand's material safety data sheet (MSDS) for the lining before purchase if chemical sensitivity is a concern.
What we don’t know
- Basis
- Model estimate, 35% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Modibodi has made none
Formulations change between production runs, so check the current label. How we grade.
Safer alternatives in Period Underwear
Modibodi
Basic Mid-Rise Period Brief
organic cotton blend with water-resistant coating
Water-resistant coating degradation
Limited concern
Microbial growth and odor with improper care
Limited concern
Lower concern. MADE SAFE certified, PFAS-free claimed and tested.
✓Lab test found no PFAS
Lola
The Lola High Waist Period Underwear
organic cotton with water-resistant treatment
Water-resistant coating degradation and microplastic shedding
Limited concern
Allergen sensitivity to cotton or treatment additives
Limited concern
Lower concern; PFAS-free certified, organic cotton base.
✓Lab test found no PFAS
Lola
Organic Cotton Period Underwear
organic cotton with gusseted absorbent layer
Formaldehyde / VOCs
Limited concern
Azo dyes and color fastness
Limited concern
Microplastic shedding
Limited concern
Lower concern. Organic cotton core, no water-resistant treatment disclosed.
⚠Risky category by default
More period underwear 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.