How the menstrual cycle affects metabolism—and what that means for diabetes

The menstrual cycle isn’t just about periods—it’s a complex hormonal rhythm that influences almost every system in the body. Our cycles can affect how well we sleep, think, and recover; how our moods and energy fluctuate; and even how our bodies use energy or respond to medications (1-3). As new research emerges, we’re learning more about how these hormonal shifts shape everyday health.

The cycle and blood sugar 

The menstrual cycle may play a role in how the body regulates glucose (or blood sugar), which is our main source of energy (3-5). Insulin is the hormone that moves glucose from the bloodstream into cells, where it’s used for fuel. When the body becomes less responsive to insulin, glucose can stay in the blood instead of being used for energy (6). This can affect how we feel and how our body works.

Hormones and insulin response

The changing levels of reproductive hormones across the menstrual cycle can influence how the body responds to insulin. This means that the same meal or insulin dose might impact blood sugar differently depending on which cycle phase you are in (7). These shifts aren’t the same for everyone: some people need more insulin after ovulation, others need less, and some see little change at all (8). Even within one person, patterns can vary from cycle to cycle, making them difficult to predict.

For most people, the body adapts to these changes on its own. But for those with type 1 diabetes (T1D), whose bodies don’t naturally produce insulin and who rely on exact doses, hormonal shifts can make managing blood sugar harder. In one study, over 60% of participants with T1D noticed changes in their blood sugar related to their menstrual cycle—changes that can influence energy, mood, and overall stability. 

Why new research matters

This is why new research is so important. Larger, more detailed studies can help us understand how hormones affect insulin and blood sugar, and why these patterns are different for each person. With this clearer picture, people with T1D could notice changes earlier, reduce trial and error in treatment, and manage their condition more confidently.

Mapping how hormones shape insulin sensitivity

To help answer these important questions, Clue is supporting a groundbreaking new study: Trajectories in Insulin Sensitivity Across Menstrual Cycles in Women With Type 1 Diabetes (TIMES).

TIMES is led by Dr. Martina Rothenbühler, Scientific Program Manager at Diabetes Center Berne in Switzerland. The study is funded by Breakthrough T1D and the Leona M. and Harry B. Helmsley Charitable Trust, and supported by Clue. It will look at how insulin sensitivity, blood sugar patterns, and daily management habits change across the menstrual cycle in people with T1D. The study will also look at how hormonal birth control affects these patterns.

Across five countries—Switzerland, Germany, Denmark, the UK, and the US—the study brings together multiple real-world data sources, including:

• Continuous glucose monitoring and insulin dosing

• Physical activity from wearables 

• Cycle-tracking data from Clue

• Ovulation tests or information on hormonal birth control use

Over several months and across thousands of cycles, the research team will look for patterns of insulin sensitivity across different phases of the menstrual cycle. What they uncover could help make diabetes care more personalized, reduce unpredictable highs and lows, make daily management easier, and guide better treatment decisions for people with diabetes and their healthcare providers.

Clue’s role in powering cycle-aware science

One of the biggest barriers to better healthcare for women and people with cycles is the lack of high-quality data. For decades, women have been left out of many medical studies, and women’s health research has not received enough funding. Because of this, healthcare systems still treat the male body as the default, and the menstrual cycle is often overlooked.

That’s why Clue is partnering with research teams around the world to help close this gap. Our goal is to make it easier for scientists and clinicians to study women’s health by providing tools to track cycles and symptoms in a way that is simple, secure, and inclusive.

Clue’s new research enrollment feature

We’ve built a new research enrollment feature in the Clue app that makes it easy for study participants to connect their app to the research study they’re enrolled in. With their permission, participants can track their cycles and related experiences in Clue, and their consented data is securely shared with the study team for analysis.

The TIMES study is the first to use this new feature, making menstrual-cycle data collection easier than ever. It shows how digital tools can bridge the gap between everyday experiences and clinical research, helping enable discoveries that were once out of reach.

Looking ahead

Supporting studies like TIMES is part of Clue’s broader mission to close the gender data gap and advance our understanding of menstrual and reproductive health. As the #1 women-led period and cycle tracker, Clue partners with researchers to ensure that the next generation of medical evidence reflects the diversity of real bodies and lived experiences.

We’re excited to see what insights the TIMES study uncovers and how its findings will help shape more personalized, cycle-aware care in the future. Stay tuned for updates as the study progresses, and for more opportunities to take part in Clue-supported research.

To learn more:

If you live in one of the participating countries (Switzerland, Germany, Denmark, the UK, or the US), you can find full eligibility details and sign up for screening here.

If you’re a researcher interested in collaborating or learning how Clue can support your work, reach out to us at research@helloclue.com.

About Diabetes Center Berne:

Diabetes Center Berne (DCB) is a private, independent Swiss foundation aiming to make life with diabetes easier.

DCB supports ideas and projects in the field of diabetes technology worldwide by providing expertise, access to clinical research facilities, and its own laboratories. Their goal is to help new ideas move closer to real-world use through collaborative partnerships. DCB is a non-profit, and its work is focused on creating new insights, innovations in diabetes management, and building a strong community.