E is for Estrogen
Estrogen plays a vital role in the brain—and understanding its influence helps us make sense of our cyclical shifts in mood, energy, and coping.
As I often say to clients: “We can’t take the brain out of the menstrual cycle.” Women’s mental health is inherently connected to the monthly rhythm and fluctuations in ovarian hormones.
Now, to be clear—the menstrual cycle isn’t everything. Not all mental health challenges are cyclical. But some are. And we’re not doing nearly enough to recognize this or integrate it into how we understand and support mental health.
In this two-part blog series, I’ll explore how the key ovarian hormones—estrogen and progesterone—impact the brain and, in turn, influence both mental health challenges and strengths.
Let’s start with estrogen.
What Is Estrogen?
Estrogen refers to a group of hormones that play a central role in the development of female sex characteristics, including breast development, hip widening, and the menstrual cycle.
There are a few different types of estrogen, but for today’s post, we’ll focus on estradiol (E2)—the type produced in the ovaries, which has the most significant neurobiological impact in the brain of a menstruating person
Estrogen in the Brain
There are estrogen receptors throughout the entire brain, meaning this hormone plays a key role in cognitive, emotional, and behavioral functions. The prefrontal cortex—a region of the brain crucial for mental health—contains one of the highest concentrations of these receptors.
The prefrontal cortex is responsible for executive functions like:
Decision-making
Emotional regulation
Stress management
Planning and memory
When estrogen levels are higher (typically in the follicular and ovulatory phases), activity in the prefrontal cortex increases. This often translates into feeling more emotionally regulated, cognitively sharp, and better able to cope with stress.
Estrogen also supports the production and activity of neurotransmitters like serotonin and dopamine—the brain's “feel-good” chemicals. This is why we often experience improved mood and energy when estrogen is on the rise.
Pretty amazing, right? The menstrual cycle actively supports nervous system regulation.
What Happens When Estrogen Declines?
Of course, estrogen doesn’t stay elevated all month. As we move into the second half of the cycle (typically the luteal phase), estrogen begins to decline. As a result, we may notice:
Increased emotional sensitivity
Lower energy
Reduced stress tolerance
Shifts in mood or motivation
For those with a history of trauma or mood disorders, this dip in estrogen can also amplify underlying symptoms. (Stay tuned for an upcoming blog post on this very topic.)
But this doesn’t mean we become dysfunctional or incapable—it simply means our needs change. During this phase of the cycle, we may benefit from more rest, intentional pacing, and deeper self-care.
A Time of Insight and Power
Interestingly, this part of the cycle also invites us inward. It's often described as the “truth-telling” time—a phase where we become more attuned to what's not working in our lives, where boundaries feel sharper, and where our inner voice grows louder.
With awareness and support, this can be a time of clarity, agency, and growth.
Why This Matters for Therapy
Estrogen plays a vital role in the brain—and understanding its influence helps us make sense of our cyclical shifts in mood, energy, and coping.
This is why therapy should consider the cyclical nature of the nervous system. A cycle-informed approach helps clients understand themselves more fully, respond with compassion to shifting needs, and build tools that align with their body’s natural rhythms.
If you're curious about how cycle-aware therapy could support your mental health or well-being, I’d love to connect.
Let’s reclaim the menstrual cycle as a source of insight, power, and healing.
Written by MC Decker, Registered Psychologist
Edited with AI technology
