Vitamin K2 has Beneficial Effects on Insulin Resistance Type PCOS

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Vitamin K2 supplementation has beneficial effects on insulin resistance type PCOS

Beneficial health effects of Menaquinone‐7 on body composition, glycemic indices, lipid profile, and endocrine markers in polycystic ovary syndrome patients


Vitamins K1 and K2 have recently attracted attention as potential micronutrients beneficial in the management of diseases associated with insulin resistance.

A previous unrelated study found that vitamin K altered glucose metabolism by improving insulin sensitivity and β-cell function.

To date studies of vitamin K supplementation, in women with PCOS, has always been combined with vitamin D preventing any individual interpretation of the results.


Women aged 18 – 40 years old with PCOS, according to the Rotterdam criteria, were recruited from the Infertility Clinic of Ghadir Mother & Child Hospital for this randomized, double-blind placebo-controlled trial.

Any women with thyroid disorders, congenital adrenal hyperplasia, Cushing syndrome, diabetes mellitus, hypertension, pregnant or lactating, on antibiotics, anticoagulants or other medication likely to interfere with the results, including specific diets or exercise plans, were automatically excluded from the study.

Following initial assessment 84 women, who satisfied the inclusion exclusion criteria, were randomly allocated to the 2 groups (treatment or control).In the treatment group, 42 women were given 90µg of Menaquinone‐7 (Vitamin K2), to take daily for 8 weeks, while the other 42 women in the control group received a placebo, identical in colour, smell, size and weight to take similarly.

The women were asked not to alter their diet or physical activity levels. Dietary intake was recorded for a 3-day period at the start and end of the trial while physical activity was measured using the validated International Physical Activity Questionnaire (IPAQ). Hirsutism and acne questionnaires were also completed pre- and post-trial to capture any changes.

Similarly, insulin resistance, lipid profile, endocrine markers (LH, FSH, TT, SHBG, DHEAS, DHT) and body composition of participants were all measured, pre- and post-trial, following a 12 hour fast on the 3rd day of the follicular cycle.


Five women withdrew from the study during the trial resulting in final group sizes of 40 and 39, in the treatment and control groups respectively

Baseline (pre-trial) characteristics showed no significant differences between the 2 groups in age, anthropometric measurements, biochemical parameters or hirsutism scores.

After 8 weeks, initial analysis confirmed that serum levels of vitamin K was significantly increased (450.20 vs. 436.95 ng/ml) in the treatment group and no changes in macro- or micronutrient intake of participants occurred during the trial.

Next analysis of anthropometric and clinical parameters showed that vitamin K2 supplementation significantly decreased waist circumference (86.25 vs. 87.00 cm) and fat mass (22.97 vs. 24.08 kg) while simultaneously increasing skeletal muscle mass (24.60 vs. 24.22 kg).

Analysis of endocrine parameters, lipid profile and glycemic indices showed that vitamin K supplementation caused significant improvements across various markers;

  • decreasing triglycerides (125.52 vs. 128.55 mg/dl)
  • decreasing fasting insulin (7.40 vs. 8.05 µIU/ml)
  • decreasing HOMA -IR (1.47 vs. 1.71)
  • decreasing HOMA-β (5.59 vs. 6.00)
  • decreasing Free Androgen Index (0.05 vs. 0.05)
  • decreasing DHT (253.70 vs. 266.9 pg/ml)
  • increasing SHBG (55.1 vs. 50.2 nmol/L)
  • increasing QUICKI (quantitative insulin sensitivity check index)

Interestingly no significant effects were seen on endocrine parameters (LH, FSH, TT, DHEAS) or other lipid markers (LDL, HDL).

Finally no adverse side effects were reported during the course of this study.


This randomized double-blinded placebo control trial, in women with PCOS, found that 90µg of Vitamin K2 daily for 8 weeks, significantly increased Sex hormone-binding globulin levels and reduced Dihydrotestosterone, resulting in lower Free Androgen Index scores and improved insulin sensitivity.


  1. Inflammatory markers or adiponectin was not measured
  2. Failed to measure carboxylated and undercarboxylated osteocalcin isoforms to assist with interpretation of the results

Similar studies

Karamali M, et al. (2017). The effects of calcium, vitamins D and K co‐supplementation on markers of insulin metabolism and lipid profiles in vitamin D‐deficient women with polycystic ovary syndrome.

Razavi M, et al. (2016). The effects of vitamin D‐K‐calcium co‐supplementation on endocrine, inflammation, and oxidative stress biomarkers in vitamin D‐deficient women with polycystic ovary syndrome: A randomized, double‐blind, placebo‐controlled trial.


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