How Your Menstrual Cycle May Affect Your Insulin Needs

For menstruating people with Type 1 diabetes, managing blood sugar is already complex. A new study published in Diabetes Care examined whether menstrual cycle hormones add another layer to that complexity—and found that they do.

Researchers wanted to know whether the hormonal shifts that happen naturally across the menstrual cycle affect how your body uses insulin, even when you're using an automated insulin delivery (AID) system like a hybrid closed-loop pump.

Seventy-seven individuals contributed real-world data from 380 menstrual cycles. Researchers analyzed continuous glucose monitor readings, insulin delivery records, food intake, and menstrual cycle information to spot patterns.

The results showed clear differences between cycle phases. During the luteal phase (roughly the second half of your cycle), people needed more total daily insulin and tended to eat more carbohydrates. Their blood sugar also ran higher during this phase, and they spent less time in their target glucose range.

In the early follicular phase (the first part of your cycle), the opposite pattern emerged: insulin sensitivity was higher, meaning bodies used insulin more efficiently. The research team estimated a 2.6% increase in insulin sensitivity in the early follicular phase compared to the midluteal phase.

While the population-level trends were clear, individual experiences varied. About 85% of study participants showed patterns matching the overall findings. This means that while cycle-related changes in insulin sensitivity are real and measurable for most people, some individuals may experience different patterns or less dramatic shifts.

This variation underscores an important point: if you track your own glucose patterns and notice cycle-related changes, that's valuable information about your individual body—and it's worth discussing with your diabetes care team.

This study provides scientific confirmation of something many menstruating people with Type 1 diabetes have observed: hormonal changes do influence blood sugar management. The findings apply to people using modern automated insulin delivery systems, which adjust insulin doses automatically based on CGM readings.

If you're interested in exploring whether your menstrual cycle affects your glucose patterns, keeping a record of both your cycle phase and your glucose data may help you and your care team identify personal trends. Some people find this information helpful for adjusting carbohydrate intake, insulin settings, or simply managing expectations during certain cycle phases.

The researchers emphasize that this is observational research describing what happens, not prescriptive guidance on what you should do. Any changes to your diabetes management should be discussed with your healthcare provider.

Source: Diabetes care. Evidence type: PubMed indexed literature. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.