MAUDE Adverse Event Report: WHOOP, INC. WHOOP 4.0; ELECTROCARDIOGRAPH SOFTWARE FOR OVER-THE-COUNTER USE

Catalog Number	W//4C2814134
Health Effect - Clinical Codes	Erythema (1840); Discomfort (2330); Skin Inflammation/ Irritation (4545)
Date of Event	10/07/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
Subject: report of skin irritation caused by whoop 4.0 fitness band dear sir/madam, i am writing to formally report a health-related issue i experienced while using the whoop 4.0 fitness band, which i purchased through flipkart india (an authorized marketplace).Within 3¿4 days of initial use, i developed skin irritation, redness, and discomfort at the site where the device was worn.Despite adhering strictly to the manufacturer's care instructions--including regular cleaning, ensuring the band was completely dry before wearing, and subsequently avoiding its use during bathing¿the irritation persisted and progressively worsened.However, based on my experience, the symptoms are consistent with a contact reaction to the material or coating of the band or sensor base.The condition has caused significant skin discomfort and raises a potential health and safety concern for other users who may experience similar reactions.I am providing this information so that it may be appropriately reviewed as a possible product-related dermatological adverse event.Please let me know if any additional details, photographs, or documentation are required to support this report.Sincerely, (b)(6).No test done but images are there.

• Brand Name: WHOOP 4.0
• Common Device Name: ELECTROCARDIOGRAPH SOFTWARE FOR OVER-THE-COUNTER USE
• Manufacturer (Section D): WHOOP, INC.
• MDR Report Key: 23342636
• Report Number: MW5177669
• Device Sequence Number: 9452209
• Product Code: QDA
• Combination Product (Y/N): N
• Initial Reporter Country: IN
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Voluntary
• Initial Reporter Occupation: Patient
• Type of Report: Initial
• Report Date (Section B): 10/15/2025

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Operator of Device: Lay User/Patient
• Device Catalogue Number: W//4C2814134
• Was Device Available for Evaluation?: Yes
• Initial Date Received by Manufacturer: Not provided
• Initial Report FDA Received Date: 10/20/2025
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Life Threatening; Required Intervention
• Patient Age: 34 YR
• Patient Sex: Male
• Patient Weight: 92 KG
• Patient Race: Asian