Changes in Blood Sugar Across the Menstrual Cycle

Changes in Blood Sugar Across the Menstrual Cycle

The menstrual cycle is a complex interplay of hormones and physiological changes that women experience each month. Beyond its impact on reproductive health, the menstrual cycle also influences various aspects of overall well-being, including blood sugar levels and energy metabolism.

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Follicular Phase:

The menstrual cycle begins with the follicular phase, which spans from the first day of menstruation to ovulation. During this phase, the hormone estrogen takes center stage. Estrogen plays a crucial role in preparing the body for potential pregnancy, and its influence extends to blood sugar regulation.

Estrogen has been shown to enhance insulin sensitivity, which means that the body’s cells become more responsive to insulin. This increased sensitivity promotes efficient glucose uptake by cells, helping to maintain stable blood sugar levels. As a result, many women experience improved blood sugar control during the follicular phase. Carbohydrate intake is better tolerated during this phase and longer fasting windows are also generally better tolerated during this time. Read my article on intermittent fasting in the menstrual cycle here

Luteal Phase:

Following ovulation, the luteal phase takes over. This phase lasts from ovulation to the onset of menstruation. During the luteal phase, progesterone becomes the dominant hormone, and its effects on blood sugar differ from those of estrogen.

Progesterone tends to decrease insulin sensitivity, leading to reduced glucose uptake by cells and a state of increased insulin resistance. This may result in slightly elevated blood sugar levels and potentially increased cravings for carbohydrates. Some women might notice that their blood sugar levels are less stable during this phase, leading to feelings of irritability or fatigue. Blood sugar imbalances can potentially contribute to symptoms of PMS. PMS and blood sugar are both further aggravated by stress or cortisol.

Blood Sugar Management

While estrogen and progesterone have contrasting effects on blood sugar regulation, the body’s intricate systems work to maintain balance throughout the menstrual cycle. These hormonal shifts influence insulin sensitivity, glucose metabolism, and the body’s energy needs. The key to navigating these changes is awareness and adopting strategies that promote stable blood sugar levels:

Balanced Diet: Prioritise a balanced diet rich in complex carbohydrates, adequate protein, healthy fats, and fibre. This can help mitigate blood sugar fluctuations and prevent sudden spikes or crashes.

Regular Meals: Aim for regular, well-spaced meals to provide a steady supply of energy to your body. This approach can help prevent extreme drops or spikes in blood sugar.

Physical Activity: Engage in regular physical activity.  Exercise helps improve insulin sensitivity and overall blood sugar control. Tailor your workout intensity to your energy levels during different phases of your cycle. For best results, its best to exercise in a fed state. This ensures the body has enough fuel and reduces the amount of cortisol needed to get through a workout. Exercising after meals also helps move glucose out of the blood and into the cells where it belongs. Rest for 15 mins following meals to allow for digestion and then exercise.

Calorie Needs and the Menstrual Cycle: Aside from blood sugar fluctuations, the menstrual cycle can also impact calorie needs. During the luteal phase calorie needs increase by up to 300 calories. Providing the body with the extra calories it needs during the luteal phase helps ensure meals last long enough to prevent blood sugar drops.

Read my article on 12 tips for blood sugar management here


Understanding how the menstrual cycle influences blood sugar levels and energy metabolism is crucial for women’s overall health and well-being. The fluctuating levels of estrogen and progesterone throughout the follicular and luteal phases play a significant role in blood sugar regulation. By being mindful of these hormonal changes and adopting a balanced approach to nutrition and lifestyle, women can manage their blood sugar levels more effectively and support their bodies throughout the entire menstrual cycle. As always, individual experiences may vary especially in cases of low hormones, so it’s important to listen to your body and consult with a healthcare professional if you have concerns about your blood sugar or dietary needs.


MacGregor, K. A., Gallagher, I. J., & Moran, C. N. (2021). Relationship Between Insulin Sensitivity and Menstrual Cycle Is Modified by BMI, Fitness, and Physical Activity in NHANES. The Journal of clinical endocrinology and metabolism106(10), 2979–2990.

Widom, B., Diamond, M. P., & Simonson, D. C. (1992). Alterations in glucose metabolism during menstrual cycle in women with IDDM. Diabetes care15(2), 213–220.

Zarei, S., Mosalanejad, L., & Ghobadifar, M. A. (2013). Blood glucose levels, insulin concentrations, and insulin resistance in healthy women and women with premenstrual syndrome: a comparative study. Clinical and experimental reproductive medicine40(2), 76–82.

MacGregor, K. A., Gallagher, I. J., & Moran, C. N. (2021). Relationship Between Insulin Sensitivity and Menstrual Cycle Is Modified by BMI, Fitness, and Physical Activity in NHANES. The Journal of clinical endocrinology and metabolism106(10), 2979–2990.


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