Herbal compounds in the treatment of polycystic ovary syndrome: an updated systematic review

Abstract

Background

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and one of the important causes of infertility due to a lack of ovulation.

Objective

Given the consideration of herbal medicines in the treatment of this condition, this systematic review was conducted to investigate the effect of herbal compounds on the treatment of PCOS.

Method

In this systematic review, all original articles on human subjects investigating the effect of medicinal plants on PCOS that were published in Farsi or English were searched in Persian (Magiran and Scientific Information Database [SID]), and English (PubMed, Scopus, Google Scholar, and Web of Science) databases until August 2025. Exclusion criteria included duplicated publications and the unavailability of full-text articles. Search keywords included polycystic ovary syndrome, medicinal plants, systematic review, Traditional medicine, clinical trial, case-control study, female infertility, and women in Persian and their English equivalents. Of the primary 182 articles, the full text of 36 articles was screened based on the inclusion and exclusion criteria. Quality assessment, including risk of bias, was performed using the Jadad checklist. Finally, ten related articles were included in the study.

Results

Out of the 10 included studies (seven conducted in Iran and one each in China, the United States, and Oman, with a total of 548 participants) were included in the review. According to the study’s results, many herbal medicines, including green tea, caraway, black mint tea, ginger, Fennel, Nigella sativa, and bitter olive, could have a significant effect on improving biochemical, hormonal, and symptoms of PCOS.

Conclusions

Medicinal plants, due to their antioxidant, anti-inflammatory, and hormone-regulatory properties, can be used to treat or reduce the complications of PCOS. However, the heterogeneity of the studies in terms of intervention, duration, and sample size requires further research to confirm the findings.

Background

Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and the most common cause of infertility due to lack of ovulation [1–3]. Based on the reported statistics, one in every 15 women of reproductive age has PCOS [4]. According to the report by the World Health Organization in 2010, about 3.4 per cent of the world population, i.e. 116 million women worldwide, suffer from this syndrome [5]. A meta-analysis study in 2020 also reported that the prevalence of PCOS was 21.27% [5]. According to a meta-analysis study published in 2015, the prevalence of PCOS among Iranian women was 19.5% [6]. An earlier study on American women reported that 9.7% of participants had diagnosed PCOS and 9.2% had probable PCOS [7].

The characteristics of PCOS include hyperandrogenism, polycystic ovaries, and ovarian dysfunction [8].Women with PCOS usually seek treatment and medical care for symptoms of menstrual disorders that include oligomenorrhea, amenorrhea, and irregular and long-term menstrual bleeding, and for clinical manifestations, including hyperandrogenism and infertility [9].

The exact etiology of PCOS is unknown, but it seems PCOS is due to a combination of genetic and environmental factors [10, 11]. PCOS increases the risk of other disorders, including type 2 diabetes, dyslipidemia, high blood pressure, cancers, infertility, and metabolic diseases such as insulin resistance [12, 13].

Conventional pharmacological interventions, such as hormonal contraceptives, insulin sensitizers, and ovulation-inducing agents are effective in symptom control, but may be associated with side effects, contraindications, or limited patient adherence [14]. This has stimulated growing interest in complementary and alternative medicine, particularly the use of herbal compounds. Herbal medicines offer a multifaceted approach by targeting hormonal regulation, insulin sensitivity, oxidative stress, and inflammation, with generally favourable safety profiles [15–17].

Various herbal remedies were assessed for the treatment of PCOS, such as Vitex agnus-castus, Cinnamon, Licorice, Green tea, Curcumin, Inositols, and Nigella sativa. Previous studies demonstrate their potential effects on the PCOS symptoms, including menstrual irregularities, hyperandrogenism, and metabolic abnormalities [18–22].

Previously published systematic reviews have shown the efficacy and safety of herbal compounds such as Ashwagandha, Aloe vera, liquorice, ginseng, cinnamon, inositol, and others in the treatment of PCOS [19, 23–25].

Considering that the long-term consequences of PCOS impose a great health and economic burden on countries, and their correct diagnosis and management can prevent its long-term complications, comprehensive studies are necessary. This updated systematic review aims to synthesize the latest evidence on the efficacy and safety of herbal compounds in the treatment of PCOS, employing a Population, Intervention, Comparison, Outcomes (PICO) framework: women diagnosed with PCOS based on Rotterdam criteria, with some referencing NIH or AE-PCOS Society guidelines.(Population), treated with herbal compounds or extracts (Intervention), compared to placebo, standard care, or other interventions (Comparison), evaluated by reproductive, hormonal, metabolic, and safety outcomes (Outcomes). By consolidating recent findings, this review seeks to provide an evidence-based update to guide clinical practice and future research directions in integrating herbal therapies into PCOS management.

Materials and methods

Study design

The Research Council of Gonabad University of Medical Sciences approved the protocol for the current systematic review. Also, the study protocol has been approved by the Ethical Committee of Gonabad University of Medical Sciences (IR.GMU.REC.1403.101). In this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed [24].

Search strategy

This study examined all articles published in domestic and international journals that investigated the effect of herbal compounds on the treatment of PCOS. The articles were extracted from Persian databases, including Magiran and SID, as well as English databases such as Web of Science, Scopus, and PubMed, and the Google Scholar search engine.

To access all Persian and English articles, keywords including polycystic ovary disease, polysystic ovarian syndrome, medicinal plants, traditional medicine, clinical trial, case-control, female infertility, women, polycystic ovary syndrome, PCOS, PCOD, Medicinal plants, Traditional medicine, clinical trial, case-control, female infertility, and a combination of these keywords were searched in both the Persian and English languages. The keywords were grouped based on the PICO items, and keywords within the same item were combined using the OR operator, while the PICO items were combined using the AND operator. The search period was performed until August 2025.

Inclusion criteria and study selection

The inclusion criteria for this study were original research articles published in Farsi or English, studies that investigated the effect of medicinal plants on the treatment of PCOS in human samples, and studies published in peer-reviewed journals by August 2025. Studies included women diagnosed with PCOS using established Rotterdam 2003, NIH 1990, or AE-PCOS scociety guidelines criteria [26]. Exclusion criteria included duplicated publications, case reports, case series, theses, reviews, and the unavailability of full-text articles.

Study selection

The articles were first selected that contained one or a combination of the previously mentioned keywords in the title or text. The EndNote software was then used to collect and combine the retrieved articles and remove duplicates. In the next step, two researchers independently performed title and abstract screening based on the inclusion criteria. After removing articles that did not meet the inclusion criteria, the full texts of all remaining articles were reviewed independently by two researchers. The remaining articles that had the required data on the outcomes were evaluated for quality. Then, the data from the full-text articles were extracted into a researcher-made table. The data were then synthesized by combining the study findings.

Initially, 182 articles were identified, of which the full text of 36 articles were reviewed. After verifying the inclusion and exclusion criteria and conducting a qualitative evaluation, 10 relevant articles were selected for the study and reviewed (Fig. 1).

Fig. 1.

Flowchart of the study (PRISMA 2020)

Quality assessment

The Jadad checklist was used to evaluate the quality of the articles in the study (Table 1). This scale is easy to use and includes important items that are empirically validated for evaluating bias. External reliability and validity were used for quality assessment in this study. The Jadad checklist criteria include (1) description of randomization (0–2 points), (2) blinding (0–2 points), and (3) attrition or withdrawal (0–1 points). The total score ranges from 0 to 5 [12].

Table 1.

Quality assessment of the included articles

Study	Randomization (0–2 points)	Blinding (0–2 points)	Attrition or withdrawal (0–1 points)	Total score (0–5)	Quality assessment
Chan (2006) [27]	2	2	1	5	Very good
Wang (2007) [28]	2	2	1	5	Very good
Bashtian (2013) [29]	2	2	1	5	Very good
Haj-Husein (2016) [30]	2	2	1	5	Very good
Jamilian (2017) [31]	2	2	1	5	Very good
Shakerian (2019) [32]	2	2	1	5	Very good
Mohammadi (2020) [33]	2	2	1	5	Very good
Bonab (2020) [34]	2	2	1	5	Very good
Mahmoudian (2024) [22]	2	2	1	5	Very good
Mahmoudian (2025) [35]	2	2	1	5	Very good

Data extraction

Data were extracted independently by three authors. Data extraction was done using a form designed for this study. The form included the following information: study title, authors, publication date, sample size, study location, and main results. Findings from studies published in Farsi were translated into English and used for synthesis. The outcome data included the clinical, imaging, and laboratory signs and symptoms of PCOS, as well as insulin resistance and metabolic profile (serum lipids and glucose levels). Studies that reported any of the mentioned outcomes were included in the review, and the results of the studies, in terms of these outcomes, were extracted. The findings of studies reporting similar outcomes were synthesized, considering other study characteristics, including sample size, intervention duration, type of intervention, and the herbal medicine used. Any additional data that could be used to discuss or assess the reliability of the studies was also extracted. In cases of ambiguity or missing data, one researcher emailed the corresponding author and requested further information. In the event of disagreement, the conflict was resolved through discussion among the three authors. If the problem remained unresolved, the fourth author was consulted to resolve the conflict.

Results

Characteristics of the included studies

A total of 10 studies, including 548 participants, were included in this systematic review. The studies were conducted between 2006 and 2025. Seven studies were conducted in Iran, while other studies were conducted in the United States, China, and Oman (one study from each country). The herbal medicines used in the studies included ginger, green tea, marjoram tea (Origanum majorana), soy isoflavones, Fennel and black cumin combination; black seed (Nigella sativa), fenugreek, and cinnamon. The duration of interventions varied between one and four months.

Randomization methods included computer-generated sequences (in 8 studies); blinding was double-blind in 7 studies, single-blind in 2, and open-label in 1; attrition rates ranged from 0 to 15%, with reasons provided (non-compliance).

The characteristics of the reviewed articles are shown in Table 2. In the following, we will examine each of the herbal medicines discussed in the articles.

Table 2.

Characteristics of the reviewed articles

Author (year)	Country	Control group	Intervention duration	Study type	Plant used/Dosage	Sample size	Outcomes	findings
Bonab (2020)[34]	Iran (Bonab City Hospital)	Pilates exercise	12 weeks	Quasi-experimental with pre-test post-test design	Ginger/Three 1 g capsules/d	40 women	Ovulatory function (LH, FSH, SHBG, testosterone, insulin)	↓ LH, testosterone, insulin ↑ FSH, SHBG
Chan (2006) [27]	China	Placebo	3 months	RCT	Green tea/2% weight/volume drink	34 women	Anthropometric measurements (weight, BMI, waist: hip ratio, triceps skinfold, body fat mass %), Biochemical (fasting insulin, fasting and 2-hour oral glucose tolerance tests, fasting G: I ratio, fasting leptin, cholesterol, triglyceride, LDL, HDL, non-HDL cholesterol) Hormonal profiles (FSH, LH, SHBG, total testosterone, free androgen index, androstenedione, DHEA-S)	No significant difference ↓ Prevalence of amenorrhea at the end of the study (non-significant)
Haj-Husein (2016) [30]	Oman	Placebo	1 month	RCT	Marjoram tea (Origanum Majorana)/0.2 g teabags twice daily	25 women	Hormonal and metabolic parameters (FSH, LH, progesterone, estradiol, total testosterone, DHEA-S, fasting insulin and glucose; HOMA-IR, and insulin: glucose ratio)	↓ HOMA-IR, DHEA-S
Jamilian (2017) [31]	Iran	Placebo	12 weeks	RCT	Soy isoflavone/50 mg/d	70 women	Anthropometric measurements (weight, BMI) Hormonal profile (Total and free testosterone, nitric oxide, total antioxidant, glutathione, malondialdehyde)	↓ Total testosterone, malondialdehyde ↑ Glutathione
Wang (2007) [28]	United States	Placebo	8 weeks	RCT	Cinnamon/333 mg capsule three times daily	15 women	Insulin sensitivity indices (fasting and 2-hour oral glucose tolerance tests, HOMA-IR, QUICKI)	↓ Fasting glucose, 2-hour oral glucose tolerance, HOMA-IR ↑ QUICKI,
Mohammadi (2020) [33]	Iran	Placebo	4 months	RCT	fennel and black cumin seed capsules (250 mg fennel + 60 mg black cumin twice daily)	70 women	PCOS symptoms (hirsutism score, menstruation pattern)	↓ Hirsutism, menstruation duration
Bashtian (2013) [29]	Iran	Placebo	8 weeks	RCT	Fenugreek/two 500 mg capsules daily + metformin	58 women	Menstruation pattern Metabolic parameters (fasting glucose and insulin, 2-hour post-prandial glucose tolerance test, HOMA-IR, fasting G: I ratio, QUICKI, SGOT, SGPT, renal profile) Hormonal parameters (LH, FSH, TSH, DSEA-S, 17 α -OHP) Ovarian ultrasound parameters	↓ Polycystic appearance in the ovaries
Shakerian (2019) [32]	Iran	Exercise	6 weeks	Experimental	Cinnamon/Three 500 mg capsules daily with exercise	40 women	Anthropometric measurements (fat mass) Biochemical measurements (fasting insulin and glucose)	↓ Insulin and glucose levels (in exercise with the cinnamon group) compared to exercise alone
Mahmoudian et al. (2025)[35]	Iran	Medroxyprogesterone	16 weeks	Randomized Controlled Trial	Nigella sativa extract, 1000 mg/day	103 (50 intervention, 53 control)	Fasting plasma glucose, 1-hour and 2-hour post-prandial glucose	↓fasting plasma glucose and 2-hour post-prandial glucose levels compared to the control (medroxyprogesterone); No significant effect on 1-hour post-prandial glucose levels.
Mahmoudian et al. (2024)[22]	Iran	Medroxyprogesterone	16 weeks	Randomized Controlled Trial	Nigella sativa extract, 1000 mg/day	103 (50 intervention, 53 control)	Ovarian volume, serum testosterone, LH, hirsutism score, menstrual disorders, anthropometric and BP measurements	↓ovarian volume, endometrial thickness, testosterone levels, LH levels, and hirsutism severity ↓menstrual irregularities compared to the control group. No significant change in DHEA/DHEA-S

FSH Follicular Stimulating Hormone, LH Luteinizing Hormone, SHBG Sex Hormone Binding Globulin, DHEA-S Dehydroepiandrosterone-sulfate, Homeostatic Model Assessment for Insulin Resistance, PCOS Polycystic Ovarian Disease, RCT Randomized Controlled Trial, BP Blood Pressure

The results of the included studies

Bonab (2020), Iran

This quasi-experimental study, with a Pilates exercise control group, investigated the effects of ginger supplementation (three 1-g capsules daily) on 40 women for 12 weeks. The intervention significantly decreased luteinizing hormone (LH), testosterone, and insulin levels, while increasing follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG). These hormonal changes suggest that ginger has a beneficial impact on ovulatory function and metabolic parameters relevant to polycystic ovary syndrome (PCOS) [34].

Chan (2006), China

In a randomized controlled trial (RCT) involving 34 women, green tea (2% weight/volume solution) was administered for 3 months compared to a placebo. The study found no significant differences in anthropometric measures, biochemical parameters, or hormonal profiles; however, a non-significant trend toward reduced amenorrhea prevalence was observed. The results suggest that green tea had a limited impact on metabolic or endocrine outcomes in this cohort [27]

Haj-Husein (2016), Oman

A 1-month RCT using marjoram tea (0.2 g teabags twice daily) in 25 women demonstrated significant improvements in hormonal (FSH, LH, progesterone, estradiol, total testosterone, and DHEA-S) and metabolic (fasting insulin and glucose; HOMA-IR, and insulin: glucose ratio) parameters. Notably, there was a reduction in insulin resistance as measured by HOMA-IR and a decrease in DHEA-S levels. These findings indicate marjoram’s potential to improve insulin sensitivity and androgen excess in women with PCOS [30].

Jamilian (2017), Iran

This 12-week RCT with 70 women tested soy isoflavone supplementation (50 mg/day) and found reductions in total testosterone and malondialdehyde, a marker of oxidative stress. Additionally, glutathione levels increased, indicating enhanced antioxidant status. These results suggest that soy isoflavones may improve hormonal balance and oxidative stress in PCOS patients [31].

Wang (2007), United States 

In an 8-week RCT of 15 women, cinnamon capsules (333 mg three times daily) improved insulin sensitivity markers (fasting and 2-hour oral glucose tolerance tests, HOMA-IR, QUICKI). There were significant decreases in fasting glucose, 2-hour oral glucose tolerance, and HOMA-IR, alongside increased QUICKI scores. Cinnamon supplementation shows promise for improving glucose metabolism in subjects with PCOS [28].

Mohammadi (2020), Iran

This 4-month RCT examined fennel and black cumin seed capsules (250 mg fennel + 60 mg black cumin twice daily) in 70 women. The intervention resulted in significant reductions in hirsutism scores and improvements in menstrual duration. These effects suggest that fennel and black cumin may help alleviate hyperandrogenism and menstrual irregularities in PCOS [33].

Bashtian (2013), Iran

A RCT involving 58 women evaluated fenugreek supplementation (two 500 mg capsules daily) as adjuvant therapy to metformin over 8 weeks. The study reported reduced polycystic ovarian morphology on ultrasound (decreased cyst size and number), favorable trends in metabolic parameters (improved insulin sensitivity), and hormonal parameters (decreased LH/FSH ratio), though some results were not statistically detailed. Fenugreek appears to exert beneficial effects on ovarian morphology and potentially on metabolic health [29].

Shakerian (2019), Iran

This 6-week experimental study compared exercise alone to exercise combined with cinnamon supplementation (three 500 mg capsules daily) in 40 women. The combination group experienced decreased insulin and glucose levels, as well as reduced fat mass, suggesting that cinnamon enhances the metabolic benefits of exercise in PCOS [32].

Mahmoudian et al. (2025), Iran

In a 16-week RCT, Nigella sativa extract (1000 mg/day) was tested against medroxyprogesterone in 103 women. The intervention significantly reduced fasting plasma glucose and 2-hour post-prandial glucose levels, although no improvement was observed in 1-hour post-prandial glucose levels. These findings support Nigella sativa’s glucose-lowering effects in managing PCOS-related metabolic disturbances [35].

Mahmoudian et al. (2024), Iran

Another 16-week RCT with 103 women assessed Nigella sativa extract, focusing on ovarian and hormonal outcomes. The supplement significantly reduced ovarian volume, endometrial thickness, serum testosterone, LH, and hirsutism severity while improving menstrual irregularities. No changes were observed in DHEA/DHEA-S levels. This result suggests that Nigella sativa may improve both reproductive and clinical manifestations of PCOS [22].

The herbs used for treating PSOS

Green tea

Green tea contains polyphenols (GTPs, AmbePhytoextracts). Green tea is obtained from the young branches of the Camellia sinensis plant. Furthermore, catechins and Flavins are considered active microbiological ingredients of green tea [36]. Green tea contains caffeine, catechins, polyphenols, vitamins B, C, E, flavonoids, glycoproteins, fiber, lipids, and carotenoids. In the past, extensive studies have been conducted on tea and its flavonoid compounds. Flavonoids are the result of the secondary metabolism of plants, which are widely found in the kingdom of plants. Flavonoids can be divided into six groups, including flavones, flavans, isoflavones, flavanols, and anthocyanins, based on the structure and position of the heterocyclic oxygen ring. The most important flavonoids in tea are flavonols or, more precisely, catechins. Catechins are antioxidants and have beneficial effects in the body. Catechins comprise 25 to 35% of the dry weight of green tea. Catechins are responsible for the biological properties of tea, including antioxidant, antimicrobial, anticancer, and anti-mutagenic properties. Free radicals can have destructive effects on cells, particularly on DNA, proteins, and lipids, and can ultimately lead to apoptosis through lipid peroxidation. It has been proven that catechin possesses free radical inhibitory properties and acts as a biological antioxidant [37, 38]. Green tea was found to reduce the serum level of inflammatory factors, including TNF-α, IL-6, and CRP, in individuals with metabolic disorders [39]. Frequent consumption of green tea may increase the levels of endogenous antioxidants, including catalase and glutathione peroxidase, in patients with type 2 diabetes and metabolic syndrome [39]. Therefore, green tea is hypothesized to play a significant role in mitigating the complications of metabolic syndrome by improving the serum sugar and lipid levels [40].

Ginger

Ginger, Zingiber officinale Roscoe, helps treat various conditions and diseases, including nausea, digestive disorders, respiratory disorders, pain, and rheumatoid arthritis, by inhibiting cell penetration. Furthermore, ginger possesses potent anti-inflammatory and antioxidant properties that help combat free radicals. Ginger contains sesquiterpenes and bisabolene, which exert their anti-inflammatory effect through direct inhibition of the cyclooxygenase and 5-lipoxygenase pathways [41, 42]. In line with its oxidative effects, numerous reports have shown that the active compounds of ginger, including gingerol, shogolol, and curcumin, could inhibit the production of free radicals. Ginger is known for its ability to inhibit the synthesis of several pro-inflammatory cytokines, including IL-1 and TNF-α [34].

Fennel

Fennel, Foeniculum Vulgare, is a herbaceous plant from the Apiaceae family. The medicinal part of this plant is the seed. Fennel seed contains a fragrance or volatile oil, and the most important component of this fragrance is trans-anethole. Other components of the fragrance include fenchone, limonene, methylcavicol, alpha-pinene, and alpha-phellandrene. Fennel has phytoestrogenic, antioxidant, and antidiabetic properties [43]. Fennel contains protein, fat, some amount of mucilage sugar, calcium, phosphorus, iron, potassium, vitamins A and C, and about 4–5% volatile oil. Fennel oil contains palmitic acid (4%), oleic acid (22%), linoleic acid (14%), and pterosilynic acid (60%). The fragrance content of Fennel includes anethole, funco, and camphene. Many researchers attribute the effects of Fennel on the female reproductive system and mammary glands to the estrogenic properties of anethole, which is present in the fragrance. It is believed that antole polymers, including diantole and photoantole, act as phytoestrogens. Due to the presence of antole, fennel fruit and its fragrance reduce or stop gastrointestinal spasms and intensify the secretion of digestive juice, and as a result, treat indigestion. These compounds are believed to be effective in treating insomnia caused by physical disorders of the gastrointestinal system. This plant exhibits analgesic and anti-spasmodic effects in spasms caused by oxytocin and prostaglandins, facilitating menstrual blood flow in a shorter period, and is also effective in reducing dysmenorrhea [43, 44].

Soy

Soy plant, which is a member of the pea family, contains phytoestrogens, including genistein, daidzein, and glycine, which are all isoflavones and act on estrogen receptors and have both agonistic and antagonistic properties. When the amount of estradiol in the body is low to compete in binding to the receptor, isoflavones provide more agonistic properties. On the other hand, their antiestrogenic properties depend on the relative concentrations of phytoestrogen and endogenous estrogen. When endogenous estrogen is abundant, phytoestrogens may displace estradiol from its receptor [45].

Cinnamon

Cinnamon (Cinnamomum verum, Lauraceae family) is used as a spice in food and medicine. Cinnamon has antimicrobial, antioxidant, antidiabetic, antiviral, and anti-spasmodic properties. It also has anti-flatulence effects, increases body sweating, heats, and stimulates the uterus. Cinnamon fragrance has antifungal and antibacterial properties, which are probably related to its orthomethoxycinnamaldehyde content. Cinnamon extract contains compounds such as eugenol, which has fibrinolytic properties. Cinnamon and its compounds can also affect the central nervous system, potentially reducing pain.

Furthermore, the compounds in cinnamon enhance insulin action and reduce insulin resistance, which has a beneficial effect on blood glucose levels. One of the most significant therapeutic effects of cinnamon is its ability to increase libido. The increase in hormones can be attributed to the direct or indirect effect of cinnamon compounds, especially cinnamaldehyde, in increasing the synthesis of nitric oxide. Cinnamon contains volatile and non-volatile phenolic and non-phenolic compounds that exhibit antioxidant properties [46].

Fenugreek

Fenugreek, Trigonella foenum-graceum L., is an annual herbaceous plant of the Legouminosae family, which is native to the Eastern Mediterranean region. Many uses have been attributed to this plant in traditional medicine. It has been used to facilitate childbirth, aid digestion, increase metabolism, and generally strengthen the body. This plant is among the most important medicinal plants in the world due to its high therapeutic potency and serves as a source of medicinal alkaloids, steroid compounds, and sapogenins. Nicotinic acid trigonelline is an important metabolite of the fenugreek plant, which may be effective in treating diabetes and reducing blood cholesterol [47].

Marjoram

Marjoram, Origanum vulgare L., is a member of the mint family, which is considered an important and best-selling medicinal and spice plant in the world. The aerial parts, especially the leaves, of various marjoram species have long been popular spices—used as flavorings in the food, perfume, and cosmetic industries. To date, a wide range of active medicinal compounds have been identified in marjoram. Marjoram fragrance contains flavonoids, tannins, glycosides, sterols, vitamins, and terpenoid compounds. Recent findings suggest that, in addition to its antibacterial, antifungal, antiviral, and anticancer properties, the active ingredients of marjoram can also be effective in improving chronic rhinosinusitis, managing diabetes, and preventing inflammation and cardiovascular diseases. Pharmacological studies have demonstrated that the high antioxidant potential of marjoram is attributed to its phenolic monoterpenes, including thymol and carvacrol, as well as other phenolic compounds such as eriganoside and rosmarinic acid. It should be noted that the last two compounds have high potential in preventing oxidative damage in the skin (melanization) and skin aging [48–50].

Nigella sativa

Nigella sativa, commonly known as black seed, has shown promising therapeutic potential in the management of polycystic ovary syndrome (PCOS) according to recent clinical and preclinical studies [51].

Multiple clinical trials have demonstrated that supplementation with Nigella sativa, particularly its bioactive compound thymoquinone, might improve hormonal profiles, including reductions in luteinizing hormone (LH), testosterone, and markers of insulin resistance. Additionally, Nigella sativa has been reported to regulate menstrual irregularities such as oligomenorrhea and amenorrhea by exerting anti-inflammatory and antioxidant effects. In randomized controlled trials, treatment with Nigella sativa extract (typically 1000 mg/day for 16 weeks) resulted in decreased ovarian volume, improved menstrual cycle regularity, and reduced severity of hirsutism among adolescent girls with PCOS [22, 35]. Preclinical animal studies further support these findings by showing that Nigella sativa enhances ovarian morphology, increases the number of healthy follicles, reduces follicular cysts, and normalizes levels of metabolic and gonadotropic hormones. These effects are comparable to those observed with standard treatments like metformin. Nigella sativa holds potential as an integrative herbal medicine for PCOS management by improving hormonal balance, reproductive function, and glycemic control [51]. However, further large-scale, long-term clinical trials are needed to validate its efficacy and elucidate precise mechanisms of action.

Discussion

PCOS is a major problem in the field of fertility and other medical fields. Women with PCOS have disorders in androgen metabolism and estrogen production. Based on the results of the previous studies, medicinal plants improve the clinical symptoms of PCOS patients.

The study by Kohzadi et al. (2017) [52] demonstrated that in the groups treated with black seed, the antioxidant capacity of ovarian tissue increased, and the level of malondialdehyde enzyme decreased, compared to the induced PCOS group. They also showed that the dose of 600 mg/kg of body weight had the most positive effect of the tested doses. Therefore, they concluded that black seed has antioxidant activity and reduces oxidative stress [52]. Recent studies have shown that black seed improves disorders of the free radical system and supports antioxidant defense mechanisms in both in vivo and laboratory conditions [53]. In a systematic review by Wani et al. (2025) [23], two studies were reviewed to assess the effects of fenugreek and black seed on PCOS, of which one was included in this systematic review. The overall findings indicated that both were safe and could potentially affect ovarian morphology and sex hormones in women with PCOS [23]. Oxidative stress can lead to an increase in androgens and insulin resistance [54]. The role of oxidative stress in the pathogenesis of PCOS is undeniable [55]. Therefore, reducing oxidative stress by increasing antioxidant enzyme activity can be an effective treatment in these patients. The results of this study showed that treatment with black seed extract increased the levels of antioxidant enzymes and decreased the levels of malondialdehyde in a PCOS mouse model. This finding is similar to the results of the study conducted by Leong et al. [56]. Naseran et al.(2020) [37] showed that treatment with the maximum dose of black seed extract and honey significantly decreased the serum levels of LH, estrogen, and testosterone in the PCOS group compared to the untreated PCOS group [37].

Furthermore, the serum levels of FSH in the PCOS group treated with the maximum dose of black seed extract and progesterone significantly increased compared to the PCOS group treated with the minimum and maximum black seed doses [37]. Therefore, the use of this medicinal plant, in combnation with hormone therapy, can be useful in improving the symptoms of PCOS. A systematic review by Ainehchi et al. (2019) [57] found that herbal medicines like cinnamon could improve insulin resistance in PCOS [57]. In another systematic review by Kwon et al. (2020) [58] on 22 herbs, the mechanisms of actions on PCOS were categorized into improving inflammation, antioxidant properties, prevention of autophagy and apoptosis, and reducing ovarian nerve growth factor (NGF) [58].

The study by Bonab et al. (2020) [34] revealed that Pilates exercises and ginger supplementation could have beneficial effects on ovarian function, suggesting this treatment as a method to improve the PCOS condition [34]. Ginger is a valuable medicinal plant with numerous properties, including benefits for the cardiovascular, immune, and digestive systems. Ginger contains antioxidants, including gingerol and shogaols, that remove free radicals from the body and prevent the production of their active metabolites in the body [57]. Therefore, it is likely that ginger could have a positive effect on ovarian tissue. The high content of reactive oxygen species (ROS) in ovarian follicles depletes the follicular fluid antioxidant system and directly damages the oocytes [59]. As a result, the use of antioxidants, including ginger, seems to be helpful for the preservation and growth of ovarian follicles, and therefore, reducing damaged follicles in the present study can be attributed to the potent antioxidants in ginger [58]. In a systematic review by Novakovic et al. (2024) [60], cinnamon and ginger were found to affect sex hormones in PCOS [60]. Therefore, combining these herbs with exercise may mitigate their therapeutic effects in PCOS.

The study by Seif Amirhosseiny et al. (2020) revealed that administering fennel extract normalized the stages of the sexual cycle, decreased the number of cystic follicles, and increased the corpus luteum [43]. One possible mechanism of these changes is the reduction of NO free radicals and an increase in the number of Treg cells [43]. Pathak et al. demonstrated that these compounds possess anti-androgenic properties, exerting their inhibitory effect on the formation of the dihydrotestosterone receptor complex and decreasing testosterone hormone secretion [61]. The study by Karampoor et al. [62] showed that fennel extract can increase the serum concentration of follicle-stimulating hormone (FSH) and decrease yolk hormone and testosterone levels in rats with PCOS [62]. Fennel is a plant with anti-inflammatory, antioxidant, and phytoestrogenic properties. Administration of fennel extract significantly reduced the number of cystic follicles [62]. One of the key features of PCOS is the decrease in ovulation rate, which results in a reduction in the number of corpus luteum in polycystic ovaries. Progesterone levels also decrease significantly in PCOS, which can be attributed to the reduction or absence of the corpus luteum in the ovary [63]. Studies indicate that flavonoid compounds in plants with antioxidant activity can reduce oxidative stress in ovarian tissue and reduce the number of cystic follicles in the ovarian tissue. Plant antioxidants also reduce the effects of hyperandrogenism following PCOS induction in mice. The anti-androgen properties of plants also reduce the amount of androgen secretion by inducing negative feedback on Luteinizing hormone (LH). The reduction of androgens leads to reduced LH synthesis, which in turn reduces the dominant effect of LH on FSH. This issue can be a reason for restarting the natural pathway of sexual cycle hormones and the occurrence of ovulation in PCOS [63, 64]. In a narrative review by Manouchehri et al. (2023) [25], the mechanism of the effects of Fennel on PCOS was attributed to sex hormone regulation based on animal studies [25].

Green tea catechins exhibit antioxidant properties that mitigate PCOS-induced damage in animal models by inhibiting free radicals, normalizing sex hormones. Flavonoids inhibit aromatase enzyme dose-dependently, reducing estradiol [25]. Senanayake et al. (2013) [65] showed green tea reduces oxidative stress, inflammation, and hormonal disorders in PCOS rats [65]. Khodarahmi et al. [66] reported decreased testosterone/estradiol and increased FSH with green tea [66]. Furthermore, green tea extract treatment significantly decreased testosterone and estradiol levels, and increased FSH levels in the ovarian damage experimental group in the mentioned study [66]. In a systematic review by Colonetti et al. (2022) [67], the effects of green tea extract on PCOS were attributed to weight management. The level of evidence in the study was reported to be low [67]. These findings were in contrast to the findings of our systematic review. The reason for this difference might be due to the difference in the included studies in the reviews.

Shakerian et al. (2019) [32] reported a significant decrease in insulin and blood glucose following the consumption of a cinnamon supplement. Cinnamon can improve insulin and blood glucose due to its ingredients that have insulin-lowering properties [32]. The study by Qin et al. also showed positive effects of cinnamon on fat-free mass, blood glucose, insulin, and insulin resistance [68]. Wang et al. and Kort et al. concluded that cinnamon extract can significantly improve fasting glucose levels, insulin resistance, and menstrual cycle symptoms in women with PCOS [28, 69]. Cinnamon can stimulate glycogen synthesis and increase glucose uptake by activating insulin receptors. Extracted bioactive cinnamon complements resemble hydroxychalcone polymers that imitate insulin action by activating the insulin kinase receptor and inhibiting the dephosphorylation of the insulin receptor, thereby maximizing insulin receptor phosphorylation. All these effects increase insulin sensitivity and decrease insulin resistance [37]. Similar findings were reported in a systematic review by Novakovic et al. (2024) [60].

Jamilian et al. (2017) [31] demonstrated that soy consumption significantly decreased total testosterone levels, but did not affect other related hormones. Soy isoflavones may modulate the activity of steroidogenic enzymes, including P450aromatase, 3-beta-hydroxysteroid dehydrogenase, and 17-beta-hydroxysteroid dehydrogenase [31] mainly through binding to the estrogen receptor. A systematic review and meta-analysis by Zilaee et al. (2020) [20] found that soy significantly reduced total testosterone in PCOS [70].

The results of the study by Bashtian et al. showed that adjunctive treatment with fenugreek seed extract and metformin improved ultrasound findings and menstrual cycle in women with PCOS [29]. Furthermore, the study by Puri et al. showed that treatment with fenugreek seed aqueous extract significantly reduced the glucose tolerance curve and improved the insulin response to glucose intake. The glucose-lowering effect may be due to the stimulation of insulin synthesis or its secretion from pancreatic beta cells in the islets of Langerhans [71]. Smith et al. also demonstrated that fenugreek seed can reduce blood sugar by inhibiting the activity of alpha-amylase and sucrase, two intestinal enzymes involved in carbohydrate metabolism, and may also reduce insulin resistance [72].

The study by Haj-Husein et al. demonstrated that the beneficial effects of marjoram tea on the hormonal profile of women with PCOS were attributed to improvements in insulin sensitivity and a reduction in the levels of adrenal androgens. More research is needed to confirm these results and investigate the active components and their mechanisms of potential beneficial effects [30].

According to the results of many studies, it can be said that many herbal medicines can be used to reduce symptoms and improve PCOS. Considering their effect on the production and secretion of essential hormones during the reproductive process, as well as their antioxidant and anti-inflammatory properties, these medicinal plants can be used as an alternative method to chemical treatments in PCOS patients. In addition to conducting more detailed and extensive research on this matter, it is advisable to exercise caution in consuming these plants to minimize their known or unknown adverse effects on reproductive health. The present study was among the few that investigated the effect of herbal medicines on PCOS, providing comprehensive information about the impact of these medicines. For this purpose, based on the findings of this systematic review, it is recommended that studies with larger sample sizes, focusing on specific outcomes (biochemical, hormonal, anthropometric, and morphological presentations of PCOS), and comparisons with different medications in terms of their mechanisms of action, be conducted.

One of the limitations of this systematic review was the inclusion of articles published only in the Farsi and English languages. Therefore, it is possible that some studies in languages other than English were not included in this study. Therefore, it is suggested that further reviews focus on a specific type of medicinal plants with no language barriers. Furthermore, the heterogeneity of the studies in terms of medicinal plant use, dosage, and extract production and also combination of medicinal plants with other medications or treatments prevented us from conducting a meta-analysis. Another limitation of this review was the lack of assessment of the possible synergistic effects of combining medicinal herbs in the management of PCOS. Therefore, further studies with similar methodology on similar plant extracts, similar to the present products in the market, are required in order to be able to get to a more definite conclusion. Another limitation of this review was the heterogeneity of the reviewed studies in terms of the PCOS treatment received. As the medications were not similar in the studies, their effects could not be compared with those of herbal medicines. Therefore, it is suggested that further studies be conducted using medicinal herbs with similar effects (insulin resistance or hormonal balancing properties) with medications with similar effects.

Conclusion

The findings revealed that herbs such as ginger, green tea, fennel, cinnamon, and Nigella sativa may have a potential complementary role in managing PCOS through different mechanisms (hormonal regulation, antioxidant effects). Furthermore, combining these herbs with non-pharmacological methods like exercise may enhance their effects. However, due to study heterogeneity, we cannot recommend herbal monotherapy; further research is needed.

Abbreviations

PCOS

Polycystic Ovary Syndrome

SID

Scientific Information Database

WHO

World Health Organization

FSH

Follicular Stimulating Hormone

LH

Leuteinizing Hormone

SHBG

Sex Hormone Binding Globulin

DHEA-S

Dehydroepiandrosterone-sulfate

RCT

Randomized Controlled Trial

TNF-α

Tumor Necrosis Factor-alpha

IL-6

Interleukin-6

CRP

C-Reactive Protein

Authors’ contributions

Study concept and design: N. B. and A.A.; analysis and interpretation of data: S. D. and N.B.; drafting of the manuscript: A.A. and N.B.; critical revision of the manuscript for important intellectual content: N. B., A.A., and S. D.; All authors read and approved the final manuscript.

Funding

This work has been supported by Gonabad University of Medical Sciences (grant: 1649).

Data availability

The data supporting this Systematic Review are from previously reported studies and datasets, which have been cited.

Declarations

Ethics approval and consent to participate

The study protocol has been approved by the Ethical Committee of Gonabad University of Medical Sciences (IR.GMU.REC.1403.101).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.