How do hormones affect your mood across your cycle?

Your mood can shift across your cycle because estrogen and progesterone rise and fall, and both may affect serotonin, a brain chemical that helps regulate mood. Many women feel brighter in the follicular phase and more sensitive or irritable in the pre-menstrual days. It varies from person to person, so your own pattern matters most.

If your mood seems to follow a rhythm, you are not imagining it, and it is not a flaw in you. It is also not the same for everyone. Some women notice very little. Others notice a lot, and it can change from one year to the next.

What do estrogen, progesterone and serotonin have to do with your mood?

Estrogen and progesterone are the two main hormones that rise and fall across your cycle. Both act well beyond your uterus, including on the parts of your brain involved in mood. You can read more in our guides to estrogen, progesterone and serotonin.

Serotonin is a brain chemical that helps regulate mood. Changes in serotonin may play a part in pre-menstrual symptoms such as low mood, irritability and trouble sleeping.¹

Experts do not know exactly why some women are affected more than others.³ The NHS notes that a high sensitivity to normal hormone changes may be involved in the most severe form of pre-menstrual mood symptoms.² In other words, it is often less about having the wrong amount of a hormone and more about how your brain responds to the change.

How can your mood change in each phase of your cycle?

These are common patterns, not rules. Your cycle may look different, especially if it is irregular.

Bleed. Estrogen and progesterone are both low as your period starts. For many women, pre-menstrual symptoms ease within a few days of bleeding starting.¹ You may still feel tired or low on the first day or two, or you may feel relief.

Follicular phase. Estrogen rises as your body builds toward ovulation. Many women find their mood, energy and motivation often lift in this stretch, and that they feel steadier.

Luteal phase. After ovulation, progesterone rises. For some women this brings a quieter, more inward mood. You may feel more tired or more sensitive than you did a week earlier.

Pre-menstrual days. Estrogen and progesterone both fall in the days before your period. That drop after ovulation may trigger symptoms in some women.³ Common ones include mood swings, irritability, anxiety, low mood, crying spells and trouble concentrating.¹,² This is what many people call PMS. For many women it follows a predictable monthly pattern.¹

Why can your mood shift more in your late 30s and 40s?

Perimenopause, the run-up to menopause, can begin as early as your mid-30s, though it more often starts in the mid-40s.⁴ During it, hormone levels do not simply fall. They can rise and fall unpredictably, which Cleveland Clinic describes as going up and down like a rollercoaster.⁴ That can make your mood feel less predictable than it used to, and a pattern you knew well may stop following the calendar.

Irritability, mood swings, anxiety and low mood are common in perimenopause.⁴ A 2016 meta-analysis found that women were more prone to depressive symptoms during perimenopause than before it, and that hot flashes and night sweats may be linked to low mood in this stage.⁵ Poor sleep can add to how you feel. None of this means you are coping badly. It is part of how this transition works for many women. Our guide to perimenopause mood swings and anxiety goes further.

When should you talk to a doctor about your mood?

Mood changes that ease once your period starts are common. It is worth talking to a healthcare provider if:

• Your mood changes affect your daily life or relationships, or lifestyle changes have not helped.¹,²

• Your symptoms before a period feel severe each month, such as extreme irritability, anxiety or depression. This can be a sign of PMDD, a more serious form of PMS that a provider can assess. Read more in our guide to PMDD.³

• Your low mood does not lift, at any point in your cycle. Some women with severe pre-menstrual symptoms also have depression, which is worth checking.¹

• You have thoughts of harming yourself or ending your life. In the US, call or text 988, the Suicide and Crisis Lifeline, or call your local emergency number.³

Only a healthcare provider can tell you what is behind a change in your mood. Asking is never an overreaction.

How can tracking your mood help?

Tracking cannot change your hormones, and it cannot diagnose anything. What it can do is show you your own pattern, which is hard to see from memory alone. The NHS suggests keeping a symptom diary for at least two menstrual cycles before you see a doctor about pre-menstrual symptoms.²

Moody is a cycle and hormone companion, not a diagnostic tool. With Moody you can:

• Log your mood, sleep and symptoms in a few taps.

• See your daily hormone forecast: a short read on what your hormones are likely doing today, and what tends to help.

• See your patterns over time, and compare how you feel with last cycle.

• Bring a clearer picture of what is changing to your doctor.

Moody works with regular, irregular and changing cycles, including perimenopause, so your mood pattern can still show up when your cycle does not follow a calendar. Your forecast is a pattern, not a prediction about your health.