Progesterone

Progesterone is a natural steroid hormone primarily produced by the ovaries, with smaller amounts secreted by the adrenal glands and placenta during pregnancy. It is one of the body’s most important reproductive hormones, working in balance with oestrogen to regulate the menstrual cycle, prepare the uterus for pregnancy, and maintain early gestation. Progesterone also helps control the secretion of luteinising hormone (LH) and follicle-stimulating hormone (FSH), supports endometrial development, and has significant effects on the brain, mood, and metabolism.

Progesterone levels normally change across different phases of the menstrual cycle and during perimenopause. The reference ranges below help interpret your progesterone result based on which phase of your cycle your blood test was taken.

Progesterone reference ranges in nmol/L:

Follicular phase: 1 - 3

Mid-cycle (ovulatory phase): 4 - 6

Luteal phase: >6

Perimenopausal: <3

Progesterone plays a key role in nearly every stage of a woman’s reproductive life. It prepares the uterine lining for implantation, maintains early pregnancy, and regulates menstrual bleeding. Beyond reproduction, it supports sleep, mood, and brain health, with studies showing that progesterone has neuroprotective and anti-anxiety effects in women.

Low progesterone levels are often associated with symptoms such as PMS, irregular or heavy bleeding, fertility challenges, anxiety, poor sleep, and hot flashes during perimenopause. On the other hand, excessive progesterone (often from hormone therapy or adrenal dysfunction) can cause fatigue, bloating, or low mood.

Progesterone naturally rises and falls throughout the menstrual cycle and life stages:

• Menstrual Cycle: Levels are low during the follicular phase, increase after ovulation during the luteal phase, and drop if pregnancy does not occur — triggering menstruation.

• Pregnancy: Progesterone levels rise dramatically to support pregnancy, maintaining the uterine lining and preventing premature contractions.

• Menopause: Levels decline sharply as ovarian function decreases, contributing to symptoms like mood changes, sleep disruption, and hot flashes.

Childhood and Puberty
Progesterone levels are minimal before puberty and increase once ovulatory cycles begin. Early cycles may be anovulatory, resulting in inconsistent progesterone production.

Reproductive Years
During the reproductive years, progesterone fluctuates predictably, peaking mid-luteal phase. It balances oestrogen and stabilises the endometrium — preventing excessive proliferation and promoting regular cycles. Low luteal progesterone can indicate anovulation, luteal phase defect, or adrenal fatigue.

Perimenopause
Progesterone is often the first hormone to decline in perimenopause, even while oestrogen remains relatively high. This imbalance — “oestrogen dominance” — can cause PMS-like symptoms, breast tenderness, anxiety, irritability, and irregular cycles.

Postmenopause
After menopause, ovarian progesterone production ceases almost entirely. The resulting low progesterone contributes to sleep problems, mood changes, hot flashes, and bone loss. Small amounts are still produced by the adrenal glands and can be supported nutritionally or, in some cases, via bioidentical hormone therapy.

If Your Progesterone Is High

High progesterone can indicate adrenal hyperactivity, thyroid dysfunction, or a side effect of certain medications.

Diet:

• Focus on whole foods and anti-inflammatory meals rich in vegetables, berries, olive oil, and lean proteins.

• Reduce alcohol, refined carbohydrates, and excess saturated fats that strain liver metabolism.

• Support liver detoxification with cruciferous vegetables (broccoli, kale, Brussels sprouts) to enhance hormone clearance.

Lifestyle:

• Prioritise stress management (yoga, meditation, nature walks).

• Maintain 7–9 hours of restorative sleep.

• Avoid anabolic steroids or unprescribed hormone therapy, which can disrupt progesterone feedback.

Supplements:

• Magnesium glycinate (200–400 mg/day) to support adrenal balance.

• Zinc (15–30 mg/day) for hormonal regulation.

• Omega-3 fatty acids (1–2 g/day) to support anti-inflammatory pathways.

Testing:

• Check cortisol (morning and evening), testosterone, and thyroid hormones to uncover root causes.

• Support liver function through hydration and, if needed, targeted detox support under medical supervision.

If Your Progesterone Is Low

Low progesterone is often linked to adrenal fatigue, chronic stress, or age-related decline. It can cause fatigue, low libido, and symptoms of oestrogen dominance.

Diet:

• Include healthy fats: avocados, olive oil, nuts, seeds, and pasture-raised eggs to provide the cholesterol backbone for hormone synthesis.

• Eat zinc- and magnesium-rich foods: oysters, pumpkin seeds, spinach, cacao, and legumes.

• Add vitamin B6 sources (salmon, chickpeas, potatoes) to support progesterone production.

Lifestyle:

• Reduce chronic stress and over-exercising; both suppress the hypothalamic-pituitary-gonadal axis.

• Engage in moderate resistance training (2–3× weekly).

• Maintain consistent sleep and meal timing to support adrenal rhythms.

Supplements (with guidance):

• DHEA (25–50 mg/day) may support hormone precursors but must be monitored by a clinician.

• Vitamin C (500–1000 mg/day) aids adrenal hormone synthesis.

• Ashwagandha (500 mg/day) may improve stress resilience and support hormonal balance.

Testing:

• Test cortisol patterns and adrenal function via salivary or urinary panels.

• Evaluate thyroid status, as hypothyroidism often coincides with low progesterone.

• Low progesterone: Fatigue, low libido, anxiety, poor sleep, mood swings, low testosterone.

• High progesterone: Brain fog, low energy, bloating, decreased libido, thyroid-like symptoms.

• Associated conditions: Hypogonadism, adrenal fatigue, thyroid disorders, chronic stress, or exposure to endocrine disruptors.

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2. Nagy, B., Szekeres-Barthó, J., Kovács, G. L., et al. (2021). Key to life: Physiological role and clinical implications of progesterone. International Journal of Molecular Sciences, 22(20), 11039. https://doi.org/10.3390/ijms222011039

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4. Caufriez, A., Leproult, R., & Copinschi, G. (2018). Circadian profiles of progesterone, gonadotropins, cortisol and corticotropin in cycling and postmenopausal women. Chronobiology International, 35(1), 72–79. https://doi.org/10.1080/07420528.2017.1381971

5. Sherman, B. M., & Korenman, S. G. (1975). Hormonal characteristics of the human menstrual cycle throughout reproductive life. The Journal of Clinical Investigation, 55(4), 699–706. https://doi.org/10.1172/JCI107979

6. Milewich, L., Gomez-Sanchez, C., Crowley, G., et al. (1977). Progesterone and 5α-pregnane-3,20-dione in peripheral blood of normal young women: Daily measurements throughout the menstrual cycle. The Journal of Clinical Endocrinology and Metabolism, 45(4), 617–622. https://doi.org/10.1210/jcem-45-4-617