WHOOP, There It Is: Lessons From WHOOP’s FDA Warning Letter

Blythe Karow [1] is a strategic management consultant and fractional executive with a biomedical engineering bachelor’s degree from Johns Hopkins University, an MBA from the UVA Darden School of Business, and over twenty years of experience leading, advising, and consulting as a medtech, digital health, wearables, and regulated healthtech expert. She is the founder of The Karow Advisory Group and author of The Device Files [2], a Substack where she shares strategy, insights, and practical tips for getting devices to market. She has covered the evolution of the WHOOP/US Food and Drug Administration (FDA) regulatory conflict since it began and shares her reflections here.

In July 2025, the fitness wearable company WHOOP received a warning letter from the FDA [3] for their “Blood Pressure Insights” (BPI) feature, noting that it was clearly a medical device requiring proper 510K clearance. For anyone following the wearables space, this wasn’t surprising. WHOOP, like many wearables companies, has slowly been evolving from performance optimization and wellness toward monitoring and diagnosing medical conditions [4].

The warning did not just kick off another regulatory spat. It raised important questions and considerations for the future of wearables and other medical devices, spurring debates across the medical device and wearables communities for 6 months, and culminating in the release of new FDA guidance on January 6, 2026 [5]. In this analysis, I review both the FDA’s and WHOOP’s original arguments around the regulatory status of the BPI feature, looking at the evolution of the conflict up until now.

Where the July 2025 FDA Warning Letter Arguments Fell Short

The "Inherent Association" Doctrine

The FDA’s original position hinged on “inherent association”—that blood pressure measurement is “inherently associated with the diagnosis of hypo- and hypertension” regardless of disclaimers or intended use [3].

In my view, this legal theory was always a bit of a stretch. If any biometric that can be used for diagnosis automatically becomes a medical device, then the wellness device exemption Congress created in the 21st Century Cures Act [6,7]—that software intended for general wellness and not medical diagnosis or treatment is not considered a medical device—becomes meaningless. By this logic, bathroom scales would be medical devices because weight is “inherently associated” with obesity diagnosis, but you can walk into any store and buy a scale without FDA oversight.

In my original analysis, I argued that the real conversation shouldn’t be whether all blood pressure measurements are inherently diagnostic, but rather how the FDA’s wellness guidelines could and should be revised to allow biomarker collection while providing clear guidance on handling detected extremes.

The Language Trap

The FDA found specific language from WHOOP that crossed into diagnostic territory, such as “higher blood pressure may be an indicator of poor sleep” and materials indicating that the feature was intended to identify “higher blood pressure” [3].

The distinction between “higher” and “high” blood pressure matters here. “Higher” describes a relative change from an individual’s baseline and should be acceptable for wellness devices. However, “high blood pressure” suggests comparison with clinical diagnostic thresholds. While WHOOP appears to have used “higher,” the FDA appeared to have interpreted this as “high blood pressure.”

The Color-Coding Absurdity

The FDA objected to WHOOP’s user insights interface, claiming the color-coded (green/yellow/orange) readings imply medical interpretation, but most fitness wearables use similar color-coding schemes: for example, Garmin shows heart rate zones in green, yellow, and red, and Apple Watch displays activity rings with traffic-light logic.

If color-coding implies medical interpretation, are we going to start requiring submissions from manufacturers of street lights? This may be a tongue-in-cheek comparison, but the question remains: when does color-coding imply diagnostic categorization?

The Misuse Argument

The FDA cited “evidence of individuals using BPI to monitor their hypertension” as a sign that WHOOP had overstepped the line. This original argument concerned me for two reasons.

First, using anecdotal misuse by some users to justify broad regulatory classification, especially when they provided no details about scale, frequency, or how this evidence was collected, would have set a concerning precedent. Second, people use fitness trackers for wellness purposes all the time, and those wellness issues often connect to more serious health conditions. Sleep quality can impact anxiety or cognitive health [8] and getting your 10,000 steps can help with overall cardiovascular wellness [9]. That shouldn’t make wellness device manufacturers liable for medical device indications.

While we want to be careful of products purposefully trying to skirt a medical device pathway, some off-label use is probably acceptable when it leads people to healthier lifestyles that could improve more serious conditions. And what’s the harm in someone with hypertension wanting to get an idea of their blood pressure, especially when the next step is probably to seek proper medical testing if they see warning signs?

Where WHOOP Might Have Been Wrong

WHOOP might have had legitimate grievances about the FDA’s approach to their BPI feature, but they also seemed to escalate the situation by (1) not adjusting their marketing or features claims early on when discussions started in May 2025, (2) continuing to leave up the “offensive” product features while arguing with the FDA, (3) making a buzzworthy end run to RFK Jr instead of working with the agency [10], and (4) having their CEO, Will Ahmed, making public statements arguing their “legal” case.

The Fatal Phrase

Buried in the FDA warning is language that likely sealed WHOOP’s fate: their website originally described the blood pressure feature as delivering “medical-grade health & performance insights” [4,11].*

That single term was regulatory poison. In the FDA’s world, “medical-grade insights” implies clinical accuracy, validation standards, and regulatory approval, whether intended or not.

My original argument: you can have a wellness device that collects medical-grade data—in fact, this is preferred, because algorithms perform best when data are high-quality [12-14]. The problem was that WHOOP had originally used the term in reference to providing medical-grade insights, implying diagnostic-level blood pressure measurement.

If WHOOP had proposed changing this language in May, the situation may have been resolved sooner. However, the back-and-forth, while refusing adjustments, seemed to have gotten the FDA’s ire up. Additionally, with Aktiia and Apple subsequently receiving clearance for blood pressure and hypertension claims [15,16], it likely became harder for the FDA to give leniency.

The Media Defense

Shortly after the FDA warning letter, WHOOP CEO Will Ahmed posted counterarguments on LinkedIn [17], making good points but ultimately overrelying on disclaimers to protect the company from oversight. In medtech, just telling consumers not to use a device a certain way often isn’t enough, especially if it contradicts other marketing claims.

There were also weaknesses in the arguments Ahmed made during his CNBC appearance at the end of August 2025 [18]:

1. He appeared to believe that wellness exemptions override the core intent of the FDA’s mission to protect patients and provide medical device oversight, stating that “Intended use is what matters—and the law agrees.” But once you make claims that your device does something a medical device does, you can’t just say, “Yeah, but we’re just here for wellness purposes,” because guess what? So are all medical devices!
2. He mentioned that their blood pressure feature requires calibration with a blood pressure cuff (a medical device), as though acknowledging reliance on a medical device made it clearer that WHOOP itself isn’t performing a medical function, but if you need a medical device to calibrate your “wellness” feature, that suggests you’re doing medical device work.
3. He claimed that WHOOP should set a new precedent because regulations could thwart tech innovation, blind to an entire medical device industry that has been innovating for decades while following the rules.
4. He claimed that WHOOP members “overwhelmingly support us fighting for [BPI].” This attempt to position himself as defending consumer access read as a deflection rather than acknowledging that the company had created a regulatory mess.

The Marketing Smoking Gun

Most damning to me when reviewing this debate is how WHOOP still structures subscription tiers, separating blood pressure insights from general “health monitoring” and bundling it specifically with FDA-cleared medical features in the highest tier [19]. They’re explicitly categorizing blood pressure insights alongside actual medical device features, telling consumers through product positioning that blood pressure monitoring belongs in the medical device category. It feels a bit like a magician’s misdirection—it implies medical device credibility to the consumer, while denying the need for medical device status to the FDA.

New Year, New Guidance

Ahmed’s claim that the FDA was “on the wrong side of the law” [18] was somewhat remarkable given the FDA’s enforcement position. WHOOP appealed the formal warning letter but continued to market much the same way throughout 2025. This could have brought additional serious legal trouble [20]; the FDA had multiple escalation options, including court orders to force WHOOP to disable blood pressure features while pursuing appeals.

I was fairly confident that WHOOP’s attempted lobbying to RFK Jr wouldn’t be effective in swaying the FDA, given the precedent set by the Aktiia and Apple clearances and additional pressure from public scrutiny. But I was wrong.

In the first week of 2026, the FDA responded with new guidance that very clearly states that they will allow blood pressure measurements via optical sensing to remain in the wellness category as long as companies make no claims to having “medical-grade” data or insights [5]. The new guidance seems an obvious win for WHOOP, and it also seems clear from current FDA Commissioner Dr Marty Makary’s comments during his January 6 interview on Fox Business News [21] that the FDA is moving to relax and clarify control and oversight in the wellness space. He stated, “We want to let companies know, with very clear guidance, that if their device or software is simply providing information, they can do that without FDA regulation.”

While the new guidance provides clear direction on whether WHOOP can market BPI, there remains a lack of clarity in a few areas. The guidance does not specifically address all of the concerns originally outlined in the warning letter (for example, it does not address whether you can use color coding in a user interface) and WHOOP does not seem to have adjusted their interface or marketing beyond specifically removing claims of “medical” or “clinical grade” in reference to BPI [4,11]. And, although multiple examples are provided on how to describe a product or its features without crossing into medical device territory, there is very little to guide developers on appropriate user interface and alerts, leaving other technologies with a great deal of gray area to navigate in the future.

Ultimately, this case has shone a spotlight on some of the weaker elements of the wellness carve out and will likely continue to play a major role in how the FDA decides to evolve in this new world of wearables, artificial intelligence, and the quantified self. We’re watching the real-time evolution of the wellness doctrine; while I expect some continued upheaval, a line appears to be forming around collecting versus interpreting user data as the new distinction between wellness and medical devices. Innovators would do well to keep a close eye on the wellness space as it continues to evolve.

*Note: Following the January 2026 FDA guidance, the WHOOP web pages were revised, and the original marketing language is no longer retrievable in the current versions.