Renato Circi & Rafaël Michali

Tell us a little more about what you’re building at Sava

At Sava, we’ve developed a new technology that allows us to monitor molecules just below the skin in real time. You can think of it as a connected patch you wear on your arm, paired with your phone, collecting molecular data continuously.

Instead of relying on occasional blood tests or finger pricks, the device continuously tracks what’s happening inside the body and turns that data into real-time insights. The goal is to take something that has traditionally required lab visits and medical equipment and make it effortless, continuous and accessible in everyday life. 

What molecules are you tracking?

Glucose is the obvious first step because it’s already a proven and meaningful signal. But there are thousands of other molecules such as inflammatory markers, hormones and metabolic signals that can provide much deeper insight into what’s happening inside our bodies.

We’re really only at the beginning of a much larger movement towards molecular tracking, which we believe will enable a far more holistic understanding of health over time.

How is Sava revolutionising precision medicine? 

Continuous glucose monitors have been transformational, particularly in proving that glucose can be reliably measured in interstitial fluid. However, traditional CGMs still have real drawbacks around user experience, cost and architectures designed primarily for single-molecule detection.

We approached the problem differently. Instead of asking “Can we measure glucose?” we asked “What is the best possible way to do it?”

Our technology relies on tiny sensors that gently sit just under the skin, without the discomfort of traditional needles. This makes the device far more comfortable to wear and much easier to produce at scale.

By using multiple microsensors, we’ve built a modular platform that can support additional molecules over time, not just glucose. This allows us to go beyond today’s wearables, which focus mainly on peripheral metrics like heart rate, oxygen and sleep, and move towards a deeper, molecular-level understanding of health.

How did you get started?

We met while studying biomedical engineering at Imperial College London and shared a desire to build something tangible — technology that could leave the lab and actually reach people.

We were drawn to health because it’s still largely reactive, with insights coming from occasional lab tests rather than continuous understanding. At the same time, wearables were starting to show how powerful real-time data could be for things like sleep and activity but there was a clear gap when it came to understanding what was happening inside the body.

It was clear there was a huge opportunity here, and we really wanted to build technology that had a clear path to actually solving this challenge in the real world, rather than research that would remain purely academic. That conviction is what led us to molecular monitoring, starting with glucose.

Tell us about your experience getting early funding, and the key lessons you learnt?  

Our first round came from two angel investors we met through our networks. They were aligned with the vision, even though they weren’t specialists in medical devices. However, it wasn’t easy. As first-time founders trying to build something highly complex, we spoke to many people before getting that first yes. Once that happened, our confidence grew. From there, we joined a life sciences accelerator and began working with more technically focused investors.

We learnt that you need a lot of energy and resilience. For the kind of company we’re building, you face many rejections—there are only a small number of investors who are truly a fit. 

At the beginning, we thought we had to tailor our pitch to different investors, but we quickly realised that was a mistake. We were adapting to what we thought people wanted to hear instead of pitching what we believed was right. Eventually something clicked: if the most truthful version of what we’re building doesn’t resonate, that investor probably isn’t right for us. Once we pitched what we believed, conversations became easier and the right investor relationships formed faster.

What surprised you about building a medical device company? 

It’s much harder than we initially thought. Early on, we tried to downplay the complexity. Over time we realised the opposite: being upfront about the real challenges is part of where the value is. Transparency helps set expectations with investors and, crucially, with employees because setbacks can mean months, not weeks.

We’ve been fortunate to build an exceptional team with resilience, people who can move from failure to failure and keep building. At the same time, you still need aggressive timelines: the balance is being ambitious while acknowledging failure is part of the journey.

Where does Sava go in five to ten years?

We’ll start with glucose, and diabetes is a major area where we can make an impact, but we don’t see Sava as a diabetes company. There is so much opportunity beyond that. 

We’re at an inflection point for health monitoring. The biggest bottleneck today is data. Without continuous, high-frequency molecular data, the next generation of health services simply can’t exist.

Until recently, minimally invasive sensing was often treated as a future promise: powerful in theory, but unproven in practice. Our recent clinical results changed that. For the first time, we’ve shown that a far less invasive approach can reliably track glucose over multiple days, performing at a level comparable to existing solutions.

For us, that marks a real shift — from proving what’s possible to focusing on how this technology can scale. With that foundation in place, glucose is just the first step. Over time, continuous molecular monitoring can support many different applications, some we can already see, such as weight loss, performance and chronic care, and others we can’t yet imagine.

The analogy we often use is the smartphone: once the platform exists, entirely new services can be built on top of it.