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Polyendocrine Metabolic Ovarian Syndrome (PMOS)


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Polyendocrine Metabolic Ovarian Syndrome (formerly known as PCOS) is one of the most common endocrine and metabolic disorders affecting girls and women worldwide. In 2026 the international consensus shifted away from the term “Polycystic Ovarian Syndrome” because the condition is not simply an ovarian disorder, nor is it defined by ovarian cysts alone. The name PMOS reflects what researchers and clinicians have increasingly recognised for years — this is a complex metabolic, hormonal, inflammatory and reproductive syndrome affecting the entire body.

In reality, many women diagnosed with the condition do not have ovarian cysts, while others with cystic ovaries may have no symptoms at all. The so-called “cysts” are usually immature follicles arrested in development because ovulation is not occurring normally.

PMOS is best understood as a syndrome of hormonal imbalance, insulin dysregulation, inflammation and oxidative stress, all of which interact with one another. One of the most significant yet overlooked features is insufficient progesterone production due to infrequent or absent ovulation.


What Happens in PMOS?

Women with PMOS commonly experience a cascade of interconnected hormonal and metabolic disturbances:

  • Irregular or absent ovulation
  • Low progesterone levels
  • Excess androgen production
  • Insulin resistance and elevated insulin
  • Blood sugar instability
  • Chronic inflammation
  • Oxidative stress
  • Weight gain and difficulty losing weight
  • Fertility problems
  • Skin and hair symptoms
  • Increased cardiovascular risk

When ovulation fails to occur, progesterone is not produced in adequate amounts because progesterone is primarily made after ovulation by the corpus luteum. This leaves oestrogen and androgens relatively unopposed, contributing to many of the symptoms associated with PMOS.

High insulin levels are another major driving factor. Excess insulin stimulates the ovaries to produce more androgens such as testosterone, while simultaneously suppressing normal follicular maturation and ovulation. This creates a vicious cycle:

High insulin → high androgens → anovulation → low progesterone → worsening hormonal imbalance.


Common Symptoms of PMOS

Symptoms vary greatly between women, and not every woman experiences all symptoms:

  • Irregular periods
  • Infrequent periods
  • Absent periods
  • Heavy bleeding or spotting
  • Anovulation
  • Infertility or difficulty conceiving
  • Miscarriage risk
  • Acne
  • Oily skin
  • Excess facial or body hair
  • Hair thinning or male-pattern hair loss
  • Deepening of the voice in severe cases
  • Weight gain
  • Difficulty losing weight
  • Cravings for sugar and carbohydrates
  • Fatigue
  • Blood sugar instability
  • Insulin resistance
  • Elevated triglycerides
  • Increased cardiovascular risk
  • Chronic pelvic pain
  • Elevated cortisol
  • High homocysteine
  • Oxidative stress
  • Inflammation
  • Mood disturbances
  • Sleep problems

PMOS is increasingly recognised as a systemic condition rather than a purely reproductive one. Many women also experience neurological, immune and inflammatory symptoms alongside the metabolic and ovarian dysfunction.


The Role of Progesterone

Low progesterone is one of the central hormonal problems in PMOS because ovulation is disrupted or absent.

Progesterone helps:

  • Stabilise blood sugar
  • Oppose excess oestrogen activity
  • Reduce androgen production
  • Support normal ovarian function
  • Calm the nervous system
  • Reduce inflammation
  • Inhibit 5-alpha reductase, an enzyme involved in androgen conversion

Progesterone deficiency can contribute to anxiety, insomnia, heavy bleeding, spotting, cravings, fluid retention and worsening androgen symptoms.

Using natural progesterone correctly can help restore balance while supporting ovarian recovery and reducing symptoms associated with androgen excess and insulin instability.


The Importance of Insulin Resistance

Insulin resistance is one of the key metabolic drivers behind PMOS.

When cells become resistant to insulin:

  • The body produces more insulin
  • High insulin stimulates androgen production
  • Ovarian function becomes suppressed
  • Ovulation becomes irregular
  • Progesterone levels decline further

This is why addressing insulin resistance is often essential before normal ovarian function can resume.

Reducing refined carbohydrates, sugars and highly processed foods can dramatically improve insulin signalling. Many women find that stabilising blood sugar is one of the most effective steps toward improving hormonal balance.


Nutritional and Lifestyle Support

Vitamin D 

Vitamin D deficiency is extremely common in women with PMOS and may contribute significantly to insulin resistance, inflammation and ovarian dysfunction. Adequate vitamin D levels appear essential for proper hormonal signalling and for progesterone to function effectively.

Inositol

Inositol has been widely studied for its ability to improve insulin sensitivity and ovarian function.

Amino Acids and Antioxidants

Oxidative stress plays a major role in PMOS. Nutrients that support antioxidant pathways may assist recovery, including:

  • N-acetyl cysteine (NAC)
  • L-arginine
  • Glycine
  • Taurine
  • Selenium
  • Zinc
  • Alpha lipoic acid
  • CoQ10

Gut and Metabolic Support

Probiotics, soluble fibre, and adequate protein intake may help support insulin regulation, inflammation and gut health.

Homocysteine

Elevated homocysteine is often overlooked in PMOS and may contribute to cardiovascular risk and inflammation. Nutrients such as vitamins B2, B6, B12, folate, zinc and trimethylglycine (TMG) may help normalise levels.


Using Progesterone in PMOS

Natural progesterone is typically used during the luteal phase — the last 12–14 days of the cycle following ovulation.

However, cycles in PMOS are often irregular or absent. In these cases, many women initially follow a regular 28-day cycle until normal ovarian rhythm begins to return.

In severe cases with significant symptoms or continuous bleeding, progesterone may sometimes be used daily for several months before cycling again. The goal is to help calm inflammation, stabilise the endometrium, reduce androgen dominance and support ovarian recovery.

Stress can sharply reduce progesterone levels, so symptoms frequently worsen during periods of emotional or physical stress.


For more information see our page on PCOS.


Research papers

The Lancet, 2026; May 12, 2026; Teede H, Khomami M, Morman R et al.

Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process

Endocrine Society press release; May 12,2026

Polyendocrine Metabolic Ovarian Syndrome: New name to improve diagnosis and care of condition affecting 170 million women worldwide

Biol Trace Elem Res. 2013 Apr;152(1):9-15
Altered trace mineral milieu might play an aetiological role in the pathogenesis of polycystic ovary syndrome

Eur Rev Med Pharmacol Sci. 2013 Feb;17(4):537-40
The Combined therapy myo-inositol plus D-Chiro-inositol, in a physiological ratio, reduces the cardiovascular risk by improving the lipid profile in PCOS patients

Gynecol Endocrinol. 2013 Apr;29(4):375-9
Endocrine and clinical effects of myo-inositol administration in polycystic ovary syndrome. A randomized study

Eur Rev Med Pharmacol Sci. 2011 Oct;15(10):1212-4
Bye-bye chiro-inositol - myo-inositol: true progress in the treatment of polycystic ovary syndrome and ovulation induction

Gynecol Endocrinol. 2012 Jul;28(7):509-15
Effects of myo-inositol in women with PCOS: a systematic review of randomized controlled trials

Minerva Ginecol. 2012 Dec;64(6):531-8
Evaluation of the treatment with D-chiroi-nositol on levels of oxidative stress in pcos patients

J Ovarian Res. 2012 May 15;5(1):14
Does ovary need D-chiro-inositol?

NIH Thursday, May 24, 2012
Progestin treatment for polycystic ovarian syndrome may reduce pregnancy chances

Clin Endocrinol (Oxf). 2012 May 10
Vitamin D in the etiology and management of polycystic ovary syndrome

Eur Rev Med Pharmacol Sci. 2012 May;16(5):575-81
The combined therapy with myo-inositol and D-chiro-inositol reduces the risk of metabolic disease in PCOS overweight patients compared to myo-inositol supplementation alone

Eur Rev Med Pharmacol Sci. 2011 Apr;15(4):452-7
Myo-inositol rather than D-chiro-inositol is able to improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial

Am J Clin Nutr 2011
Higher Protein Diet Helpful in PCOS

Fertil Steril. 2011;96:1128-1133
Metformin in Polycystic Ovarian Syndrome and Infertility

Gynecol Endocrinol. 2010 Apr;26(4):275-80
Insulin sensitiser agents alone and in co-treatment with r-FSH for ovulation induction in PCOS women

J Steroid Biochem Mol Biol. 2010 Oct;122(1-3):42-52
Insulin and hyperandrogenism in women with polycystic ovary syndrome

Human Reproduction 2009 24(11):2924-2930
Thyroid-stimulating hormone is associated with insulin resistance independently of body mass index and age in women with polycystic ovary syndrome

Gynecol Endocrinol. 2009 Aug;25(8):508-13
Efficacy of myo-inositol in the treatment of cutaneous disorders in young women with polycystic ovary syndrome

Fertil Steril. 2009 Jul;92(1):328-43
Melatonin and the ovary: physiological and pathophysiological implications

Rev Obstet Gynecol. 2009 Fall;2(4):232-9
Polycystic ovary syndrome: a major unrecognized cardiovascular risk factor in women

Gynecol Endocrinol. 2008 Mar;24(3):139-44
Myo-inositol administration positively affects hyperinsulinemia and hormonal parameters in overweight patients with polycystic ovary syndrome

Med Hypotheses. 2007;68(3):480-3
Polycystic ovary syndrome in men: Stein-Leventhal syndrome revisited

Endocr Pract. 2002 Nov-Dec;8(6):417-23.
Effects of d-chiro-inositol in lean women with the polycystic ovary syndrome

Biol Reprod. 1993 Oct;49(4):647-52
Pathologic effect of estradiol on the hypothalamus

Eur J Endocrinol. 2009 Oct;161(4):575-82. Epub 2009 Jul 23.
Association of hypovitaminosis D with metabolic disturbances in polycystic ovary syndrome

Endocrine Abstracts (2009)
Prolonged treatment with N-acetylcysteine and L-arginine restores gonadal function in patients with PCO syndrome

Med Hypotheses. 2009 Jun;72(6):647-51
Poor vitamin D status may contribute to high risk for insulin resistance, obesity, and cardiovascular disease in Asian Indians

Advances in Experimental Medicine and Biology 2009, Volume 643, Pages 353-358
Taurine Supplementation and Pancreatic Remodeling

Diabetes. 2008 Oct;57(10):2619-25
Baseline Serum 25-Hydroxy Vitamin D Is Predictive of Future Glycemic Status and Insulin Resistance

Diabetologia Issue Volume 51, Number 1 / January, 2008
Vitamin B12 and folate concentrations during pregnancy and insulin resistance in the offspring: the Pune Maternal Nutrition Study

Early Human Development Volume 83, Issue 10, October 2007, Pages 693-696
Neonatal taurine administration modifies metabolic programming in male mice

Human Reproduction 2007 22(12):3264
Calcium homeostasis and anovulatory infertility

Eur Rev Med Pharmacol Sci 2007; 11 (5) : 347-354
Randomized, double blind placebo-controlled trial: effects of Myo-inositol on ovarian function and metabolic factors in women with PCOS

The Journal of Clinical Endocrinology & Metabolism 2007, Vol. 92, No. 7 2726-2733
Insulin and Insulin-Like Growth Factor Stimulation of Vascular Endothelial Growth Factor Production by Luteinized Granulosa Cells: Comparison between Polycystic Ovarian Syndrome (PCOS) and Non-PCOS Women

Exp Clin Endocrinol Diabetes. 2006 Nov;114(10):577-83
Low serum 25-hydroxyvitamin D concentrations are associated with insulin resistance and obesity in women with polycystic ovary syndrome

European Journal of Endocrinology, 2006 Vol 154, Issue 1, 141-145
Metabolic syndrome in polycystic ovary syndrome (PCOS): lower prevalence in southern Italy than in the USA and the influence of criteria for the diagnosis of PCOS

Clinical Chemistry 51: 1691-1697, 2005
Serum Parathyroid Hormone Concentrations Are Increased in Women with Polycystic Ovary Syndrome

The Anatomical Record 2005 Volume 231, Issue 2 , Pages 185 - 192
Changes in ovarian morphology and serum hormones in the rat after treatment with dehydroepiandrosterone

American Journal of Clinical Nutrition, Vol. 79, No. 5, 820-825, May 2004
Hypovitaminosis D is associated with insulin resistance and cell dysfunction

The Journal of Clinical Endocrinology & Metabolism 2004, Vol. 89, No. 5 2160-2165
Increased C-Reactive Protein Levels in the Polycystic Ovary Syndrome: A Marker of Cardiovascular Disease

Clin Endocrinol 60(5):560-567, 2004
Plasma Homocysteine in Polycystic Ovary Syndrome: Does it Correlate With Insulin Resistance and Ethnicity?

Int J Mol Med. 2004 Aug;14(2):207-15
Induction of polycystic ovary by testosterone in immature female rats: Modulation of apoptosis and attenuation of glucose/insulin ratio

STEROIDS Volume 69, Issues 11-12 , October-November 2004, Pages 763-766
Licorice reduces serum testosterone in healthy women

Am Fam Physician. 2004 Jan 15;69(2):264-266
Use of Metformin Is a Cause of Vitamin B12 Deficiency

Am Fam Physician. 2003 Mar 1;67(5):979-986
Vitamin B12 deficiency

Comparative Biochemistry and Physiology Part A 136 (2003) 95
Hyperinsulinemic diseases of civilization: more than just Syndrome X

Clinical Diabetes October 2003 vol. 21 no. 4 186-187
Glucose, Advanced Glycation End Products, and Diabetes Complications: What Is New and What Works

J Intern Med. 2003 Nov;254(5):455-463.
Effects of short-term treatment with metformin on serum concentrations of homocysteine, folate and vitamin B12 in type 2 diabetes mellitus: a randomized, placebo-controlled trial.

J Clin Endocrinol Metab. 2003 Dec;88(12):5907-13.
Altered cortisol metabolism in polycystic ovary syndrome: insulin enhances 5alpha-reduction but not the elevated adrenal steroid production rates.

Human Reproduction, Vol. 17, No. 6, 1459-1463, June 2002
Luteal phase progesterone excretion in ovulatory women with polycystic ovaries

Gynecologic and Obstetric Investigation and Vol. 53, No. 3, 2002
The Plasma Homocysteine Levels Are Increased in Polycystic Ovary Syndrome

Human Reproduction, Vol. 16, No. 10, 2061-2065, October 2001
Effects of androstenedione, insulin and luteinizing hormone on steroidogenesis in human granulosa luteal cells.

Prim. Care Update Ob Gyns 2001 Jan;8(1):12-17
The low-carbohydrate diet in primary care OB/GYN.

The Journal of Clinical Endocrinology & Metabolism 2001, Vol. 86, No. 6 2453-2455
Low Grade Chronic Inflammation in Women with Polycystic Ovarian Syndrome

New England Journal of Medicine , 340(17), 1999, pages 1314-1320.
Ovulatory and Metabolic Effects of D-Chiro-Inositol in the Polycystic Ovary Syndrome

Steroids. 1999 Jun;64(6):430-5
Vitamin D and calcium dysregulation in the polycystic ovarian syndrome

Gynecol Endocrinol. 1998 Feb;12(1):29-34.
Effects of estradiol and an aromatase inhibitor on progesterone production in human cultured luteal cells.

Archives of Environmental Contamination and Toxicology Volume 3, Number 4 / December, 1975: 479-490
Prolonged ingestion of commercial DDT and PCB; effects on progesterone levels and reproduction in the mature female rat.

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