Key Hormones: Estrogen, Progesterone, Testosterone

Estrogen, progesterone, and testosterone are essential for reproductive health in all people, regardless of gender. These hormones work together to regulate ovulation, sperm production, and the overall environment needed for conception and pregnancy. Disruptions or imbalances can affect your chances of becoming pregnant or maintaining a healthy pregnancy, and may also impact sexual function and well-being.

In the United States, infertility affects about 1 in 8 couples, and hormone-related issues are a common cause. Estrogen and progesterone are crucial for preparing the uterus and supporting early pregnancy, while testosterone is vital for sperm production and sexual health in all bodies. Understanding your hormone levels and how they interact can empower you to make informed decisions about your fertility journey. You are not alone—many people face these challenges, and compassionate, evidence-based support is available.

Why are estrogen, progesterone, and testosterone called the “Big Three” fertility hormones?

Estrogen, particularly estradiol, is fundamental for the development and maintenance of reproductive organs, regulation of the menstrual cycle, and preparation of the endometrium for implantation. In ovaries, estrogen promotes follicular growth and triggers the luteinizing hormone (LH) surge necessary for ovulation. In males, estrogen is crucial for modulating libido, erectile function, and spermatogenesis, acting through estrogen receptors in the brain, testes, and reproductive tract. Disruptions in estrogen signaling can impair both female and male fertility. Follicle Growth Chart

Progesterone is indispensable for ovulation, endometrial receptivity, and the maintenance of early pregnancy. It transforms the endometrium into a receptive state for embryo implantation and supports gestation by modulating immune responses and uterine quiescence. Progesterone also acts as a precursor for other steroid hormones and is involved in feedback regulation of the hypothalamic-pituitary-gonadal axis. Imbalances in progesterone can lead to infertility, recurrent pregnancy loss, or gynecological disorders. Short Luteal Phase

Testosterone is essential for spermatogenesis, sexual differentiation, and libido in males, but also plays a significant role in female reproductive physiology. In ovaries, testosterone acts as a precursor for estrogen synthesis and directly influences follicular development and ovarian function. In both sexes, testosterone supports sexual function and overall reproductive health. Abnormal testosterone levels can result in impaired gamete production, sexual dysfunction, or polycystic ovary syndrome (PCOS) in females.

How do these hormones rise and fall during a typical menstrual cycle?

During the follicular phase, which begins on the first day of menstruation and lasts until ovulation, both estrogen and progesterone are at their lowest. As the phase progresses, estrogen (mainly estradiol) rises steadily, stimulating the growth of the uterine lining and the maturation of ovarian follicles. This rise in estrogen is gradual at first, then accelerates as ovulation approaches, peaking just before the release of the egg. Progesterone remains low throughout this phase, while testosterone shows a modest increase near ovulation, supporting libido and follicle development.

Ovulation marks the transition between the follicular and luteal phases. The surge in estrogen triggers a spike in luteinizing hormone (LH), which causes the mature follicle to release an egg. Around this time, estrogen reaches its highest level, and testosterone also peaks briefly. Progesterone begins to rise, but is still lower than estrogen at the moment of ovulation 1.

The luteal phase follows ovulation and is characterized by a sharp increase in progesterone, produced by the corpus luteum. Progesterone prepares the uterine lining for possible implantation and helps maintain early pregnancy if conception occurs. Estrogen remains moderately high but does not reach the pre-ovulatory peak. If pregnancy does not occur, both progesterone and estrogen levels fall rapidly in the late luteal phase, leading to the shedding of the uterine lining and the start of a new cycle. Testosterone levels remain relatively stable and low during this phase. Healthy Uterine Lining.

It’s important to note that while these patterns are typical, there is significant individual variability in the timing and magnitude of hormone changes, especially in the length of the follicular phase and the duration of elevated progesterone in the luteal phase.

What signs and lab markers point to a hormone imbalance?

Signs of hormone imbalance can show up as changes in your menstrual cycle (irregular, missed, or very heavy periods), unexplained weight changes, acne, hair loss or excess hair growth, mood swings, low energy, and changes in libido. You might also notice hot flashes, night sweats, breast tenderness, or trouble sleeping. In people with ovaries, symptoms like infertility, polycystic ovary syndrome (PCOS), or early menopause can signal hormone issues. In people with testes, low testosterone may cause fatigue, reduced muscle mass, or erectile dysfunction 3.

Lab markers help confirm hormone imbalances. Key tests include blood levels of estradiol (a form of estrogen), progesterone, and testosterone. Other important markers are follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which regulate the menstrual cycle and ovulation, and sex hormone-binding globulin (SHBG), which affects how much active hormone is available in your body. In some cases, thyroid hormones and prolactin are also checked, since thyroid or pituitary problems can mimic or cause reproductive hormone imbalances. For PCOS, elevated LH, FSH, insulin, and sometimes testosterone are common, along with increased oxidative stress markers. If you notice persistent symptoms, talk to your healthcare provider about targeted hormone testing to get a clear diagnosis and personalized care. Sperm Morphology Basics.

How do the Big Three shape male fertility?

Testosterone, estrogen, and progesterone each play distinct but interconnected roles in shaping male fertility. Testosterone is the primary driver of male reproductive health, essential for the development and maintenance of male reproductive organs, the initiation and maintenance of spermatogenesis (sperm production), and the regulation of libido and sexual function. High concentrations of testosterone within the testes are necessary for sperm development, acting through androgen receptors in Sertoli and Leydig cells; disruptions in testosterone signaling or androgen receptor function can lead to impaired sperm production and infertility.

Estrogen, mainly in the form of estradiol produced locally in the testes via the aromatization of testosterone, is also crucial for male fertility. It modulates libido, erectile function, and, importantly, spermatogenesis at multiple levels—from the hypothalamic-pituitary-gonadal axis to direct effects on testicular cells and sperm maturation. Estrogen receptors are widely distributed in the male reproductive tract, and both insufficient and excessive estrogen can disrupt sperm production and function. Knockout studies and clinical observations show that loss of estrogen signaling leads to abnormal sperm, impaired fluid reabsorption in the reproductive tract, and infertility.

Progesterone’s role in male fertility is less direct but still significant. While not a dominant hormone in males, progesterone and its metabolites can influence sperm function, particularly by activating the CatSper calcium channel, which is essential for sperm motility and the ability to fertilize an egg. Progesterone’s effects are most pronounced during the sperm’s journey in the female reproductive tract, where it helps trigger the hyperactivation needed for successful fertilization.

Together, these “Big Three” hormones interact in a finely tuned balance: testosterone supports sperm production, estrogen ensures proper sperm maturation and reproductive tract function, and progesterone fine-tunes sperm activity at the final stage. Disruption in any of these pathways, whether through hormonal imbalance, receptor dysfunction, or environmental factors, can compromise male fertility.

Which lifestyle changes best balance fertility hormones?

Balancing fertility hormones; estrogen, progesterone, and testosterone, relies on several key lifestyle changes that support overall reproductive health.

• Maintaining a healthy weight is crucial, as both obesity and being underweight can disrupt hormone production and ovulation or sperm quality; weight loss in those with obesity and weight gain in those who are underweight can restore hormonal balance and improve fertility outcomes.
• Adopting a Mediterranean-style diet rich in antioxidants, omega-3 fatty acids, fiber, plant-based proteins, and low-glycemic foods helps regulate insulin, reduce inflammation, and support hormone synthesis, while limiting trans fats, refined sugars, and processed foods is equally important.
• Regular moderate physical activity enhances hormone regulation, reduces stress, and improves ovulatory function, but excessive or intense exercise can have the opposite effect, so balance is key.
• Managing stress through techniques like mindfulness, yoga, or cognitive behavioral therapy is beneficial, as chronic stress can disrupt the hypothalamic-pituitary-gonadal axis and impair hormone balance.
• Adequate, consistent sleep is also essential, since poor sleep can alter reproductive hormone levels and menstrual regularity.
• Avoiding smoking, excessive alcohol, and recreational drugs is strongly recommended, as these substances are linked to hormonal disturbances and reduced fertility in all bodies.
• Reducing exposure to endocrine-disrupting chemicals such as those found in some plastics, pesticides, and personal care products can further protect hormone health.
• For some, supplementing with key nutrients like folic acid, vitamin D, and iodine may be necessary, especially if deficiencies are identified.

Integrating these lifestyle changes holistically, rather than focusing on a single factor, offers the best chance of restoring and maintaining balanced fertility hormones.

When are medical or supplement interventions needed—and which ones work?

Medical or supplement interventions are needed when lifestyle changes alone do not restore hormone balance or fertility, or when you have a diagnosed condition such as polycystic ovary syndrome (PCOS), low ovarian reserve, or unexplained infertility. You should seek medical evaluation if you have irregular cycles, no periods, persistent symptoms, or if you have tried to conceive for 12 months (or 6 months if over age 35) without success.

Medications:

• Clomiphene citrate and letrozole stimulate ovulation in people with ovaries.
• Gonadotropins (follicle-stimulating hormone [FSH], luteinizing hormone [LH]) are used in assisted reproductive technology (ART) for those who do not respond to oral agents.
• Selective estrogen receptor modulators (SERMs) like clomiphene and tamoxifen can improve sperm motility and hormone profiles in people with testes.
• Growth hormone supplementation may benefit those with poor ovarian response, improving live birth rates and embryo quality.

Supplements:

• Antioxidants (coenzyme Q10, vitamin E, vitamin C, selenium, zinc, folic acid, carnitines) can improve sperm quality and may support egg health.
• Inositol and vitamin D are sometimes used in PCOS to improve ovulation and metabolic health.
• Zinc sulfate and CoQ10 have shown positive effects on sperm concentration and testosterone levels. Pair with strategies in Strong Egg Mitochondria.

When to use:

• If you have a diagnosed hormone disorder (e.g., PCOS, hypogonadism, poor ovarian reserve).
• If you are undergoing ART or have failed to conceive after a year of trying.
• If lab tests show persistent hormone imbalances despite lifestyle changes.

A recent systematic review found that “all interventions had a significantly positive effect on male infertility,” with supplements, SERMs, and hormone therapies each improving different aspects of sperm health and hormone levels. “Medical and supplement interventions should be tailored to your unique diagnosis and fertility goals. Work closely with your reproductive endocrinologist to choose evidence-based options that maximize your chances of success.” — Serena H. Chen, MD, Director, Division of Reproductive Medicine, Saint Barnabas Medical Center.

If you are considering supplements, discuss them with your healthcare provider to ensure safety and effectiveness. Not all supplements are regulated, and some may interact with medications or underlying conditions.

How can you track and interpret your hormone data at home?

You can now track and interpret your hormone data at home using a range of user-friendly tools. At-home urine hormone monitors such as Mira, ClearBlue, and Inito—quantitatively measure key fertility hormones like luteinizing hormone (LH), estrone-3-glucuronide (E3G, an estrogen marker), and pregnanediol glucuronide (PdG, a progesterone marker). These devices use test strips and smartphone apps to display daily hormone levels and trends, helping you pinpoint ovulation, confirm fertile windows, and identify hormonal imbalances. Studies show these monitors are highly accurate, with strong correlations to laboratory blood tests and ultrasound-confirmed ovulation, even in people with irregular cycles or during life transitions like postpartum and perimenopause.

Wearable and noninvasive sensors are emerging, allowing continuous hormone tracking through sweat or saliva, and early research shows these methods closely match blood hormone levels. Most users find these technologies easy to use, low-stress, and helpful for understanding their cycles and reproductive health. To interpret your data, look for patterns: a mid-cycle LH surge signals ovulation, rising PdG confirms ovulation occurred, and E3G trends help map your fertile window. If your cycles are consistently irregular, or if you see abnormal hormone patterns, share your results with your healthcare provider for further evaluation.

According to a 2023 study in Scientific Reports, “at-home fertility monitors can accurately capture hormone trends and confirm ovulation, providing reliable fertility scores and supporting clinical decision-making”. Tracking your hormone data empowers you to make informed choices about your reproductive health and seek timely care when needed.

What emerging or overlooked factors can disrupt or enhance these hormones?

Emerging and often overlooked factors that can disrupt or enhance fertility hormones include circadian rhythm disruption, chronic stress, environmental exposures, and micronutrient status. Disrupted sleep patterns or shift work can alter the body’s circadian clock, leading to irregular hormone secretion and impaired fertility by affecting the hypothalamic-pituitary-gonadal axis and the timing of hormone release. Chronic psychological or physical stress raises cortisol, which can suppress reproductive hormones like luteinizing hormone (LH), estradiol, and progesterone, leading to irregular cycles and reduced fertility.

Exposure to endocrine-disrupting chemicals (EDCs) such as phthalates, bisphenol A (BPA), pesticides, and perfluoroalkyl substances (PFAS), is increasingly recognized as a major disruptor of estrogen, progesterone, and testosterone signaling in both men and women. These chemicals can mimic or block hormone action, alter hormone synthesis, and impair gamete quality, embryo development, and implantation, with higher EDC levels linked to subfertility and poor outcomes in assisted reproduction. Even low-level, chronic exposure to EDCs in daily life can have cumulative effects, and mixtures of chemicals may be more harmful than single exposures.

On the positive side, adequate intake of essential minerals such as selenium, zinc, and copper, supports hormone regulation, oocyte and sperm quality, and reduces oxidative stress, while toxic metals like cadmium and lead are harmful. Adopting a Mediterranean-style diet, maintaining a healthy weight, and minimizing exposure to pollutants and EDCs can enhance hormone balance and fertility. Addressing these emerging and overlooked factors is crucial for optimizing reproductive health in modern environments.

Rapid-fire answers to reader FAQs

Can hormonal birth control cause long-term imbalance?
Most people’s hormone levels return to baseline within a few months after stopping hormonal birth control. There is no strong evidence that combined hormonal contraceptives (pills, patch, ring) cause permanent hormone imbalance or infertility. They can, however, temporarily mask underlying cycle issues, which may become apparent after discontinuation. The American College of Obstetricians and Gynecologists (ACOG) confirms that fertility typically resumes quickly after stopping birth control.

Does dairy hurt or help estrogen?
Dairy contains small amounts of naturally occurring estrogens, but for most people, moderate dairy intake does not significantly alter estrogen levels or disrupt hormone balance. There is no conclusive evidence that dairy harms reproductive hormone health in humans. Maintaining a healthy body weight and balanced diet is more important for hormone regulation than dairy intake alone.

Can men take progesterone?
Progesterone is not routinely recommended for men. While it plays a role in male reproductive health, supplementing with progesterone can disrupt the balance of other hormones, potentially leading to side effects such as reduced libido, mood changes, or impaired fertility. Progesterone therapy in men is reserved for specific medical conditions and should only be used under medical supervision.

How soon after balancing hormones can I conceive?
Once your hormones are balanced—whether through lifestyle changes, medication, or both—many people can conceive within a few cycles. For some, conception may occur as soon as the first ovulatory cycle after balance is restored; for others, it may take several months, depending on age, underlying health, and other fertility factors.

Final Thoughts

The “big three” fertility hormones (follicle-stimulating hormone (FSH), luteinizing hormone (LH), and growth hormone (GH)) work together to regulate your reproductive health. FSH and LH, produced by the pituitary gland, are essential for egg and sperm development, ovulation, and hormone production in both women and men. Growth hormone, though less discussed, plays a key supporting role by enhancing the effects of FSH and LH, improving egg and embryo quality, and supporting ovarian and testicular function. Imbalances in any of these hormones can disrupt ovulation, sperm production, or implantation, making them central to both natural conception and assisted reproductive technologies.

Recent research highlights that optimizing these hormones through lifestyle, medical, or targeted supplement interventions can significantly improve fertility outcomes, especially for those with diminished ovarian reserve or poor response to treatment. Understanding and monitoring your hormone levels empowers you to make informed decisions and seek timely care. As one review notes, “the GH/IGF axis may directly regulate female and male gamete development, their quality, and ultimately competence for implantation”. Supporting the balance of FSH, LH, and GH is foundational for your reproductive journey.

Ready for the next step? Explore Boost Uterine Blood Flow or pinpoint your Implantation Window to keep momentum. Understanding your hormones today brings the relief—and results—you’ve been hoping for.

References

1. Quantitative Hormone Analysis Reveals Sources of Variability in the Menstrual Cycle. Women in Sport and Physical Activity Journal. https://doi.org/10.1123/wspaj.2023-0062

2. The effect of menstrual cycle phase changes on error scores in Sportive Movements in female athletes… The Physician and sportsmedicine. https://doi.org/10.1080/00913847.2025.2477977

3. The impact of endocrine disruptors on early pregnancy and clinical outcomes in IVF. Human Reproduction. https://doi.org/10.1093/humrep/dead093.110

4. Toward At-Home and Wearable Monitoring of Female Hormones: Emerging Nanotechnologies and Clinical Prospects… ACS sensors. https://doi.org/10.1021/acssensors.4c02877

5. A wearable aptamer nanobiosensor for non-invasive female hormone monitoring… Nature nanotechnology. https://doi.org/10.1038/s41565-023-01513-0

6. Effectiveness of Pharmacological Intervention Among Men with Infertility: A Systematic Review and Network Meta-Analysis. Frontiers in Pharmacology, 12. https://doi.org/10.3389/fphar.2021.638628

7. The effect of growth hormone supplementation in poor ovarian responders undergoing IVF or ICSI: a meta-analysis of randomized controlled trials. Reproductive Biology and Endocrinology : RB&E, 18. https://doi.org/10.1186/s12958-020-00632-w

8. Antioxidant Supplementation on Male Fertility—A Systematic Review. Antioxidants, 12. https://doi.org/10.3390/antiox12040836

9. Growth hormone in fertility and infertility: Mechanisms of action and clinical applications. Frontiers in Endocrinology, 13. https://doi.org/10.3389/fendo.2022.1040503

10. Growth hormone supplementation ameliorates blastocyst euploidy rates and improves pregnancy outcomes in women undergoing preimplantation genetic testing for aneuploidy cycles. Frontiers in Endocrinology, 14. https://doi.org/10.3389/fendo.2023.1117706

11. Dietary supplements in polycystic ovary syndrome–current evidence. Frontiers in Endocrinology, 15. https://doi.org/10.3389/fendo.2024.1456571

12. Effects of endocrine disrupting compounds on female fertility… Best practice & research. Clinical obstetrics & gynaecology, 102347. https://doi.org/10.1016/j.bpobgyn.2023.102347

13. Elevated serum malondialdehyde (MDA), insulin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid- stimulating hormone (TSH), and reduced antioxidant vitamins in polycystic ovarian syndrome patients. Narra J, 2. https://doi.org/10.52225/narra.v2i1.56

14. The crucial role of estrogen/androgen hormones and their receptors in male infertility risk. **, 1, 35-43. https://doi.org/10.22034/CAJMPSI.2021.01.06

15. Validation of urinary reproductive hormone measurements using a novel smartphone connected reader. Scientific Reports, 13. https://doi.org/10.1038/s41598-023-36539-w

16. Tip-Enhanced Sub-Femtomolar Steroid Immunosensing via Micropyramidal Flexible Conducting Polymer Electrodes for At-Home Monitoring of Salivary Sex Hormones… ACS nano. https://doi.org/10.1021/acsnano.3c08315

17. Survey Analysis of Quantitative and Qualitative Menstrual Cycle Tracking Technologies. Medicina, 59. https://doi.org/10.3390/medicina59091509