Mobile App for the First Wearable for Active Nitric Oxide
Health, Wellness & Fitness Startup in Seattle, WA
Turning complex fitness science into a user-friendly mobile app
When NNOXX Co-Founder and CEO Justin Saul reached out about his vision for a groundbreaking wearable fitness device, we were immediately interested. The wearable measures active nitric oxide (PNO), which regulates of blood flow and oxygen delivery to muscles, and plays a critical, multifaceted role in brain health.
Unlike traditional fitness trackers, NNOXX’s unique focus on nitric oxide presents an educational challenge: many users may be unfamiliar with what it does, and how it is measured. To address this, the objective was to research, strategize, and design an intuitive MVP mobile experience that effectively engages users across varied age groups, fitness goals, and tech proficiency levels.
Screens from the app design process.
Guiding NNOXX from concept to wearable health MVP
Slide UX led the end-to-end design of the NNOXX mobile app MVP, guiding the product from early discovery through final delivery.
Strategy & Planning
Facilitated stakeholder workshops to align on goals and vision
Defined proto-personas and key user tasks to inform design decisions
Conducted a competitive review of similar products in the market
Interface Design & Usability Testing
Explored multiple visual directions to refine the app’s look and feel
Created wireframes, and built an interactive prototype for stakeholder and user feedback
Conducted usability testing with target users to validate the experience
Draft pixel-perfect, dev-ready designs for essential screens
Final Delivery
Iterated on designs based on test findings to improve usability
Delivered a comprehensive style guide and developer-ready assets for handoff
“Aha!” moments from our research
During usability testing, we learned that accommodating users of all age groups and experience levels meant that the mobile app needed to offer more flexibility and customization than originally anticipated.
We also learned just how unfamiliar users were with the role nitric oxide can play in gauging personal wellbeing. Our team adjusted the designs to provide even more education and guidance than originally planned.
Screens showing real-time feedback from the wearables during an exercise session.
“Our project was no easy task. From initial discussions to ongoing discussions to user feedback, the requirements constantly changed. Slide UX took a heavily scientific app, and made it easy. We were delighted! ”
Early successes for NNOXX
NNOXX is already seeing strong early traction. As of June 2025, NNOXX had already:
Launched the first wearable to non-invasively measure bioactive nitric oxide (NO), a vital molecule for oxygen delivery and vascular health.
Earned the trust of NFL, NBA, NHL, MLB, and Olympic teams, as well as CrossFit Games athletes and UFC fighters.
Integrated with lead fitness platforms including Oura, Garmin, Peloton, and Strava
Garnered third-party press coverage and video reviews from users
“NNOXX is easy to use.”
See how NNOXX delivers personalized health insights
Lessons learned about a smooth MVP launch
What drove the success of the NNOXX Mobile App project? Strong client collaboration, a focused MVP mindset, and a highly adaptable team.
Slide UX addressed minor challenges quickly so they didn’t impact delivery. The project strengthened both our client relationship and internal design processes, setting a strong foundation for future work in brain health, wellness, and wearable tech space.
Other reminders that came from this project:
Prioritize MVP Discipline
Continually questioning whether features belonged in the MVP scope helped the team stay focused and deliver a lean, high-value product.
Proactive Planning Pays Off
Establishing design systems and color/type early makes things faster in the later stages.
Client Collaboration is Critical
The client’s clear, fast feedback and team-based decision-making significantly contributed to the project's steady progress and ultimate success.
Adaptability Matters
Even with late-stage scope adjustments and overlapping project steps, our team’s ability to adjust quickly ensured a seamless delivery.
“Working with Slide UX was like a fluid conversation; our progress made the project a highlight of each week.”
For Slide UX, client experience is everything.
At Slide UX, we apply the same user-centered focus to our client experience as we apply to the end-user experience. Client satisfaction is key, and that’s why clients come back time after time.
Here’s how NNOXX rated their experience working with us.
NNOXX CEO and Co-Founder Justin Saul rated Slide UX 5 stars across the board in a third-party interview after the project.
Read the full review.