Written by Taylor Woosley, Science Writer. Twice daily supplementation of 500 mg garlic powder (standardized to contain 2-3 mg of allicin) resulted in a significant reduction in weight (p<0.001), BMI (p=0.007), FBS (p<0.001), TG (p=0.002), LDL-C (p<0.001), TC (p<0.001), CRP (p<0.001), and improved quality of life questionnaire scores (p<0.05 for all subdomains) in women with PCOS.

Polycystic ovary syndrome (PCOS) is a common systemic endocrine, metabolic, and reproductive disorder in women, with a prevalence of 4%-20%¹. Clinical features of PCOS include hirsutism (excessive hair growth on certain parts of the body), irregular menstruation, and polycystic ovaries, along with symptoms such as depression, obesity, and metabolic disturbances². Roughly half of women diagnosed with PCOS will go on to develop insulin resistance, dyslipidemia, or type 2 diabetes, all markers of metabolic syndrome (MetS), before menopause³.

Garlic, a popular herb used for centuries, is renowned for its potent antioxidant and anti-inflammatory properties⁴. The therapeutic properties of garlic, namely the high content of organosulphur compounds such as alliin, allicin, diallyl disulphide, and ajoene, are thought to be responsible for its medicinal properties⁵. Research on the robust sulfur-containing bioactive compounds in garlic showcases the potential lipid-lowering and antihypertensive effects through its ability to alleviate oxidative stress and inflammation, while improving insulin resistance⁶.

Hesari et al. conducted a randomized, double-blind, placebo controlled clinical trial to investigate the effects of garlic supplementation on MetS components in women with PCOS. Subject inclusion consisted of PCOS and MetS diagnosis (based on the Rotterdam criteria and NCEP ATP III guidelines), non-pregnant, being of Iranian nationality, no self-reported chronic diseases, with a fasting blood glucose <126 mg/dl, who did not consume more than one clove of garlic per day. Demographic data was collected at the start of the study and included information on age, weight, education level, marital status, and occupation.

97 subjects were randomly allocated to either the garlic (n = 48; mean age 32.6 ± 6.47; mean weight 89.79 ± 9.96 kg) or placebo group (n = 49; mean age 31.67 ± 6.16 years; 88.05 ± 13.96 kg) for an 8-week intervention period. Those in the garlic group were instructed to consume one garlic tablet an hour before lunch and an hour before dinner. Each tablet contained 500 mg of garlic powder and was standardized to contain 2-3 mg of allicin.

Overnight fasted blood samples of participants were collected at both baseline and at week 8 to assess fasting blood glucose (FBS) levels, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Additionally, total testosterone (TT), sex hormone-binding globulin (SHBG), and C-reactive protein (CRP) levels were measured. Anthropometric measurements (weight, height, waist circumference (WC), hip circumference (HC)) and blood pressure levels were also obtained. A female sexual function index (FSFI) was utilized to assess sexual function over the last four weeks, with questions focused on 6 domains: desire, arousal, lubrication, orgasm, satisfaction, and pain. Subjects also completed the modified polycystic ovary syndrome health-related quality of life questionnaire (MPCOSQ).

Primary study outcomes included significant changes in mean values of MetS indices (FBS, TC, TT, and SHBG), along with CRP levels. Secondary study outcomes were increases in participants’ sexual function and quality of life scores based on questionnaire results. Data was assessed using ANCOVA and Multivariate Analysis of Covariance (MANCOVA). No significant differences were noted between the intervention and control group regarding demographic data or WC, HC, BMI, systolic blood pressure, and FBS, TG, HDL-C, LDL-C, TC, CRP, SHBG, and TT (all p>0.05). The only notable difference between groups was slightly higher diastolic blood pressure levels observed in the intervention group (p=0.04).

Significant findings of the 8-week intervention were as follows:

• 500 mg of garlic powder twice daily resulted in a significant reduction in weight (p<0.001), BMI (p=0.007), WC (p=0.02), HC (p<0.001), SBP (p<0.001), and DBP (p=0.001) compared to placebo.
• The garlic group exhibited statistically significant improvements in reductions in FBS (p<0.001), TG (p=0.002), LDL-C (p<0.001), TC (p<0.001), CRP (p<0.001), along with an increase in SHBG levels (p=0.005).
• ANCOVA test findings indicate a significant improvement in all six MPCOSQ subdomains in the garlic group, with significantly higher scores being reported at week 8 in the intervention group compared to placebo (p<0.05 for all subdomains).

Results of this 8-week randomized, double-blind, placebo-controlled study demonstrates the beneficial impact of 500mg standardized garlic powder supplementation on key factors of metabolic syndrome, namely improved anthropometric indices and significant reductions in fasting blood glucose, CRP levels, and lipid profiles in women with PCOS. Study limitations include the short follow-up period, lack of hormone testing, and absence of information regarding subjects’ diet, activity levels, and medication use. Longer term studies with larger sample sizes are needed to better comprehend the effects of garlic supplementation on MetS components in PCOS subjects.

Source: Hesari, Naiiere Gharagozloo, Shahideh Jahanian Sadatmahalleh, Parvin Mohebbi, Malihe Nasiri, and Ahmad Khosravi. “Efficacy of garlic (Allium sativum) on metabolic syndrome components in women with polycystic ovary syndrome: randomized controlled trial.” Journal of Health, Population and Nutrition 44, no. 1 (2025): 282.

© The Author(s) 2025. Open Access

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Posted January 8, 2026.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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