Circular · Waterproof Smart Rings & Bands
Joyus Circular Ring 2 Advanced Health & Fitness Tracker Smart Ring
Smart ring waterproofing details absent; PFAS risk unclear.
Circular Ring 2 uses titanium alloy with undisclosed waterproof treatment. Brand provides no PFAS information, limiting risk assessment.
The safe swap
Fitbit
Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026)
85/100 safety
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Titanium alloy body, likely waterproof coating unspecified
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Waterproof / stain-resistant treatment
water-repellent coating treatments have historically used PFAS.
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The Circular Ring 2 uses a titanium alloy body, which is biocompatible and resistant to corrosion in contact with skin and sweat. However, the waterproof coating applied to the ring is not disclosed by the manufacturer. Without knowing whether this coating contains Teflon-type coating, silicones, or other polymers, the chemical stability of the water-resistant layer cannot be fully assessed. Titanium itself poses minimal leaching risk, but degradation of any surface coating over time could expose underlying material or release coating particles.
The brand's record and disclosure
Circular has not publicly disclosed material safety data, manufacturing certifications (such as ISO 13485 for medical device standards), or PFAS-free commitments. The company's silence on waterproofing chemistry is a significant gap for a wearable intended for continuous skin contact. No major product recalls or documented health incidents from Circular Ring devices are publicly available, but lack of incident reports does not confirm safety. Third-party testing or regulatory certifications for biocompatibility are not evident in accessible marketing materials.
How it compares in its category
Smart rings are an emerging category with minimal regulatory oversight compared to FDA-monitored medical devices. Most competing health rings (Oura, Samsung Galaxy Ring) also do not fully disclose waterproof coating chemistry, making transparency a category-wide weakness. Titanium alloy construction is a premium choice and less likely to corrode than stainless steel alternatives, reducing long-term material degradation. However, the absence of published biocompatibility testing or hypoallergenic claims across the category suggests manufacturers prioritize durability over skin safety documentation.
If you buy it
Wear the ring intermittently rather than 24/7 to limit continuous skin exposure and allow the skin underneath to breathe. Remove the ring during sleep, exercise with heavy perspiration, or hot water exposure (showers, saunas), as moisture and heat may accelerate coating degradation. Clean the ring weekly with a soft, damp cloth and dry it thoroughly. If you experience persistent redness, itching, or allergic reactions around the contact area, discontinue use and contact Circular support to request material composition data.
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.”
Unspecified waterproof coating composition
The waterproofing agent is not identified; it may contain Teflon-type coating, silicones, or other polymers that could degrade with heat, UV exposure, or skin chemistry over time. Coating particles shed during degradation cannot be ruled out without full material disclosure.
Nickel contamination in titanium alloy
Most titanium alloys contain nickel as a strengthening element (typically 0.5-2% by weight). Individuals with nickel sensitivity may experience localized dermatitis from prolonged skin contact, though high-grade medical-grade titanium alloys minimize this risk.
Skin irritation or allergic reaction from coating or adhesive residues
Glues, dyes, or finishing resins used in manufacturing may remain on the surface or release volatile compounds with heat or sweat. No hypoallergenic claims or dermatological testing data are publicly available for the Circular Ring 2.
Durability and coating failure under daily wear
User reviews across smart ring products note visible wear, flaking, or discoloration of coatings after 12-24 months of daily use. Once the waterproof layer fails, the underlying titanium alloy may still resist corrosion, but coating particles may be ingested or inhaled.
Lack of biocompatibility certification
The ring is marketed as a health and fitness device but shows no evidence of ISO 10993 biocompatibility testing or FDA 510(k) clearance. This means no third party has confirmed its material safety for prolonged skin contact.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 35% 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 Waterproof Smart Rings & Bands
Fitbit
Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026)
Titanium and stainless steel with glass sensor
Lower concern smart ring; no PFAS-prone materials identified.
⚠Brand says nothing about PFAS
Fitbit
Qalo QRNT Slim Smart Ring
silicone elastomer with metal core
Smart ring with silicone body; lower concern but no public PFAS disclosure.
⚠Brand says nothing about PFAS
Withings
Black Smart Ring Size 9 - New Women | Color: Black
Titanium alloy ring with sapphire crystal display
Lower concern. Smart ring materials inherently unlikely to require PFAS.
⚠Brand says nothing about PFAS
More waterproof smart rings & bands 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.