From WHOOP to DiGA: Where the Wellness Line Becomes a Regulatory Minefield

What Sparked the WHOOP FDA Warning, and Why Does it Matter?

The recent FDA Warning Letter issued to WHOOP over its Blood Pressure Insights (BPI) feature has triggered widespread debate across the digital health and wearables community. For some, it’s a sign of regulatory overreach. For others, it’s a textbook example of why even the best-intentioned consumer health technologies must still respect the line between wellness and medical device claims.

But for those of us working in that grey zone, whether through the lens of U.S. FDA regulations or Germany’s DiGA Fast Track, this case is less about confrontation and more about clarity. The question is no longer “Is blood pressure a medical claim?” The answer is yes. The real question is: How can innovators, investors, and regulators work together to ensure promising tools don’t fall between systems?

When Does a Wellness Feature Become a Regulated Medical Device?

WHOOP’s misstep wasn’t in building a feature that estimated blood pressure. Many wearable technology companies are exploring passive BP tracking using photoplethysmography (PPG) and machine learning. The problem was the combination of:

• Displaying systolic/diastolic values in mmHg.

• Using a colour-coded interface to imply healthy vs. abnormal ranges.

• Promoting the feature as part of their “medical-grade insights” suite.

While WHOOP pointed to disclaimers stating that the feature was not for clinical use, the FDA made its position clear: intended use is defined by function, not disclaimers. Under 21 CFR §801.4 and Section 201(h) of the FDCA, a product’s intended use is based on design, function, and how the average user would interpret its outputs.

In short: if your wearable health tracker walks, talks, and graphs like a diagnostic device – it probably is one.

How Does the DiGA Fast Track Handle Grey Areas in Digital Health?

In Germany, the DiGA framework (Digitale Gesundheitsanwendungen) provides a clearer, but stricter path. To qualify for the BfArM DiGA directory, developers must demonstrate:

• A medical device classification (typically Class I or IIa under MDR).

• Evidence of positive healthcare effect (either medical benefit or patient relevant procedural improvement).

• Transparent documentation on risk, interoperability, data protection, and intended use.

If a digital product claims to estimate or trend blood pressure, it would not qualify as a non-medical wellness app. Nor can it bypass scrutiny just by using “passive tracking” language. BP sits in the same high-alert zone as glucose, ECG, and pulse oximetry — biomarkers that even when used for general insight, cross into clinical decision territory.

In fact, several DiGA submissions in recent years have been rejected precisely for walking this line – providing health-related data without demonstrating the evidentiary burden expected for regulated medical devices. 

Is the FDA’s ‘Inherent Association’ Rule Overreaching, or Necessary?

WHOOP and some of its defenders have criticised the FDA’s use of the “inherent association” doctrine – the idea that certain metrics (like BP) are so tightly linked to diagnosis and clinical thresholds that any estimation of them constitutes a medical function.

While the legal theory deserves rigorous scrutiny, it’s important to note: blood pressure is not just a wellness metric, or a risk factor – it is a diagnosis.

Unlike weight or BMI, which are often cited in wellness tools but do not by themselves trigger ICD codes, systolic and diastolic BP thresholds define hypertension, inform medication decisions, and carry direct billing and safety implications. 

That’s why blood pressure monitors fall under 21 CFR 870.1130, and why mmHg-estimating tools – even as “trends” – cannot fall under the FDA’s 2016 Wellness Device Guidance or Germany’s “Gesundheits-Apps ohne Zweckbestimmung” (non-MDR wellness apps). 

What Can Digital Health Startups Learn from the WHOOP Case?

WHOOP’s case is unlikely to be an isolated one. As more digital health tools increasingly blur the line between self-optimisation and clinical relevance, companies must recognise that language, interface, and data presentation carry regulatory weight.

We need:

• Clearer international harmonisation on what counts as a medical claim.

• Pre-market advisory pathways for wellness-focused products.

• A way for companies to seek early regulatory input without triggering full medical device classification prematurely.

Germany’s BfArM has made progress with transparent DiGA guidance, but even there, borderline apps often fail due to vague claims or insufficient evidence. Likewise, the FDA’s Wellness Guidance – now almost a decade old – may need updating to reflect the reality of AI-driven biosensor consumer tools. 

How Do We Balance Innovation and Responsibility in Wearables?

WHOOP’s case isn’t just about wearable device. It highlights the growing tension between consumer empowerment and regulatory oversight. If the industry is serious about using data to help people take charge of their health, it must also be serious about regulatory responsibility. 

The DiGA model offers some valuable lessons, but only if startups, funders, and regulators stop treating “wellness” as a loophole and start treating it as a legitimate health category with real-world implications.

References

• FDA Warning Letter to WHOOP, Inc. (CMS #709755) – U.S. Food and Drug Administration. July 14, 2025.
• Federal Food, Drug, and Cosmetic Act (FDCA), Section 201(h) – 21 U.S.C. §321(h)
• 21 CFR §801.4 – Intended Use Definition
• 21 CFR 870.1130 – Non-invasive Blood Pressure Measurement System
• FDA General Wellness: Policy for Low Risk Devices – Guidance Document, January 2016
• Digitale Gesundheitsanwendungen (DiGA) Fast-Track Process – BfArM Guidance (English)
• Medical Device Regulation (EU) 2017/745 – Official Journal of the European Union

Disclaimer. The views and opinions expressed in this article are solely those of the author and do not necessarily reflect the official policy or position of Test Labs Limited. The content provided is for informational purposes only and is not intended to constitute legal or professional advice. Test Labs assumes no responsibility for any errors or omissions in the content of this article, nor for any actions taken in reliance thereon.