Hormones 101 support

Hormones 101 support

Hormones are your body's chemical messengers. Small signals with wide reach. They shape your energy, sleep, mood, skin, cycle, and much more.

For women, the conversation becomes more layered in perimenopause — the transitional years that often begin in the late 30s or 40s, when these messengers start to shift in new and sometimes unpredictable ways. Knowing their names is the first step toward understanding what your body is telling you.

– Pt.1 The Core Reproductive Hormones
– Pt.2 The Conductors of the Cycle
– Pt.3 The Stress & Energy Hormones
– Pt.4 The Thyroid Family
– Pt.5 The Mood & Wellbeing Messengers
– Pt.6 Key terms to know

Pt. 1 — The Core Reproductive Hormones

These hormones drive the menstrual cycle, fertility, and many of the shifts women notice during perimenopause and menopause.

Estrogen
Is a group of hormones. The three main forms are estradiol, estrone, and estriol.

Estradiol (E2) is the dominant estrogen during the reproductive years and is produced primarily by the ovaries.
Estrone (E1) becomes more prominent after menopause and is produced mainly through conversion of adrenal hormones in fat tissue.
Estriol (E3) rises significantly during pregnancy and is produced primarily by the placenta.

Estrogen affects many systems across the body, including bone density, skin, vaginal and urinary tissues, the cardiovascular system, and the brain.

Progesterone
Progesterone is made mainly after ovulation. It helps regulate the menstrual cycle, supports sleep, and prepares the uterus for pregnancy. In early perimenopause, ovulation becomes less consistent, so progesterone production can drop while estrogen continues to fluctuate. Lower progesterone exposure may contribute to shorter or irregular cycles, heavier bleeding, disrupted sleep, and mood changes.

Testosterone
Women produce testosterone in the ovaries, adrenal glands, and other tissues. Levels are lower than in men, but testosterone still contributes to sexual desire, muscle maintenance, bone health, and general wellbeing. Levels decline gradually with age. Some women notice shifts in libido, energy, or motivation during midlife.

DHEA (Dehydroepiandrosterone)
DHEA is produced mainly by the adrenal glands and acts as a precursor to estrogen and testosterone. Levels peak in early adulthood and decline with age. After menopause, adrenal-derived hormones and peripheral hormone conversion take on a larger role as ovarian production decreases.

Graph showing the menstrual cycle with hormone levels over time

Pt. 2 — The Conductors of the Cycle

These hormones come from the brain and coordinate the conversation with the ovaries.

FSH (Follicle-Stimulating Hormone)
This hormone is made by the pituitary gland (a pea-sized endocrine organ located at the base of the brain) and prompts ovarian follicles to mature. As ovarian reserve and responsiveness decline with age, FSH often rises. The brain has to send stronger signals to get a response from the ovaries. FSH levels can fluctuate noticeably during perimenopause.

LH (Luteinizing Hormone)
LH triggers ovulation mid-cycle. Levels may also rise during reproductive aging as ovarian feedback shifts.

GnRH (Gonadotropin-Releasing Hormone)
GnRH is released by the hypothalamus (a small, almond-sized structure deep within the brain that acts as your body's control center). It tells the pituitary gland to release FSH and LH, keeping the reproductive hormone system in sync.

AMH (Anti-Müllerian Hormone)
AMH reflects ovarian reserve and declines with age. AMH testing offers information about reproductive aging, but it cannot predict fertility or the exact timing of menopause for any one woman.

Pt. 3 — The Stress & Energy Hormones

These hormones interact closely with the reproductive system and shape sleep, metabolism, and stress in midlife.

Cortisol
The body’s main stress hormone, produced by the adrenal glands (small, triangular-shaped endocrine glands located on top of both kidneys). It follows a daily rhythm — higher in the morning, lower at night — and helps regulate metabolism, blood sugar, immune function, and inflammation. Hormonal shifts during perimenopause may change stress sensitivity, sleep quality, and mood.

Adrenaline & Noradrenaline
These fast-acting fight-or-flight hormones shape the body’s stress response and temperature regulation. Changes in norepinephrine signalling are thought to play a role in hot flashes and night sweats.

Insulin
Insulin moves glucose from the blood into cells. During and after menopause, changes in estrogen, body composition, and age can lower insulin sensitivity and raise the risk of central weight gain and type 2 diabetes.

Pt. 4 — The Thyroid Family

Thyroid hormones regulate metabolism, body temperature, energy use, mood, and many other functions. Thyroid disorders are common in women and often overlap with perimenopausal symptoms.

TSH (Thyroid-Stimulating Hormone)
TSH is produced by the pituitary gland and tells the thyroid to make thyroid hormones. It is the most common screening test for thyroid function.

T4 (Thyroxine) & T3 (Triiodothyronine)
T4 is the main hormone released by the thyroid and works largely as a precursor to T3, the more biologically active form. Low thyroid hormone levels can contribute to fatigue, weight gain, cold intolerance, hair thinning, constipation, and low mood.

Pt. 5 — The Mood & Wellbeing Messengers

These brain chemicals work alongside the endocrine system and shape mood, motivation, sleep, and emotional life.

Serotonin
It is a neurotransmitter involved in mood, appetite, and sleep. Estrogen interacts with serotonin pathways, so hormonal shifts during perimenopause may affect mood for some women.

Dopamine
Dopamine shapes motivation, reward, pleasure, and goal-directed behaviour. Estrogen and testosterone both influence dopamine signalling, which can affect energy, libido, and motivation during hormonal transitions.

Melatonin
Melatonin is made by the pineal gland and helps regulate sleep and circadian rhythms. Production declines with age. Sleep disruption during perimenopause is also shaped by night sweats and hormonal fluctuations.

Oxytocin
Oxytocin is involved in childbirth, breastfeeding, social bonding, and emotional connection. It also plays a role in stress regulation and social behaviour.

Pt. 6 — Key Terms to Know

Perimenopause
The transitional years before menopause, when hormone levels fluctuate and cycles become less predictable. Perimenopause often begins in the 40s, though some women notice changes in their late 30s. It can last several years. Read more: The stages of menopause

Menopause
Menopause is defined as 12 consecutive months without a menstrual period. The average age of menopause in the United States is around 51.

Postmenopause
The years after menopause. Hormone levels generally settle at lower levels than during the reproductive years.

Relative Estrogen-Progesterone Imbalance
In early perimenopause, ovulation can become less consistent. Progesterone exposure drops while estrogen continues to fluctuate. This pattern may contribute to heavier bleeding, breast tenderness, bloating, and mood changes.

HPA Axis
The hypothalamic-pituitary-adrenal (HPA) axis regulates the stress response and works closely with the reproductive hormone system.

Endocrine System
The endocrine system is the network of glands and organs that produce hormones, including the ovaries, adrenal glands, thyroid, pituitary gland, and pancreas. These systems communicate through hormonal feedback loops that regulate metabolism, reproduction, stress, sleep, and more.

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While this Hormone 101 Support is carefully written and references peer-reviewed sources. It is for informational purposes only and is not medical advice.

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