Plenty of herbal teas and other natural remedies have been recommended for centuries to improve symptoms of PCOS. But is green tea good for PCOS? Green tea is a staple beverage in many homes around the world. But can it impact symptoms of PCOS like inflammation and insulin resistance? Let’s evaluate the evidence.
What is PCOS?
Polycystic ovary syndrome (PCOS) is a hormonal disorder common among people assigned female at birth (AFAB) of reproductive age, affecting approximately 6% to 20% of this population. People with PCOS may experience a range of symptoms due to an imbalance of reproductive hormones. These symptoms include irregular or extended menstrual periods, excess hair growth, acne and skin tags.
PCOS is a complex disorder and is thought to be caused by environmental factors, metabolic dysfunction, genetic factors and more. Insulin resistance, inflammation, and hormonal imbalances, particularly elevated androgen levels, are central to the condition.
Management of PCOS symptoms and improving quality of life is the usual treatment plan for those living with PCOS. PCOS cannot be cured but instead, medication, dietary supplements, nutrition changes, regular movement, stress management and sleep hygiene can be used to manage the syndrome.
What is green tea?
Green tea is a type of tea made from the leaves and buds of the plant Camellia sinensis that has not undergone the same withering and oxidation processes used to make other teas such as black tea and oolong tea. The history of green tea traces back to China around 2737 BC, making it one of the oldest beverages consumed by humans. It is believed to have been a part of Chinese culture for over 3000 years.
The production of green tea is distinctive because it involves the application of heat to the fresh, unrolled, and unoxidized leaves, stopping the oxidation process that would otherwise turn the leaves into black tea. This step is critical and what defines the character of green tea. The bioactive compounds in green tea leaves, such as catechins and polyphenols, are responsible for many of its health benefits, including antioxidant properties that can reduce the production of free radicals in the body, which play a role in ageing and various diseases.
In regards to preparation and consumption, green tea is best brewed with water at a mild temperature of 180°-185° F (approximately 82.2°-85° C) and steeped for about 3 minutes to avoid releasing too many tannins, which can make the tea taste astringent. High-quality green teas can be steeped multiple times before the flavour starts to degrade. The gentle flavour and perceived health benefits contribute to its popularity and it is thought that green tea production will continue to rise to meet global demand.
Does green tea have benefits for PCOS?
There are several studies on green tea and its potential benefits for PCOS. A recent study published in 2021 reviewed studies from 1960 to January 2021 and found that green tea and its derivatives might help alleviate some symptoms of PCOS, particularly in relation to anti-inflammatory effects, reduction of testosterone levels, and improvements in insulin resistance status. However, the review noted inconsistencies across various clinical trials and animal studies and suggested that more research is needed. Let’s take a deeper look at more studies below.
PCOS is a multifaceted disorder but one contributor and symptom of PCOS is chronic low-grade inflammation. People with PCOS often exhibit elevated levels of inflammatory biomarkers such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNF-α).
A 2014 study investigated the effect of green tea on inflammatory markers in a PCOS model using adult Wistar rats. After the induction of PCOS, the rats were divided into control and experimental groups, with the experimental groups receiving daily intraperitoneal injections of green tea extract. There was a significant reduction in the levels of IL-6 and CRP in the rats treated with green tea extract compared to the control group, indicating the anti-inflammatory properties of green tea. As with all animal studies, the applicability to human physiology is not direct, and further research, including clinical trials in humans, would be necessary to confirm these findings and their relevance to human PCOS treatment.
However, a 2017 randomised clinical trial comparing green tea tablet supplementation with a placebo group found no significant difference between the two groups on inflammatory markers.
In summary, the evidence for green tea consumption and its effect on inflammation in people with PCOS is emerging, and more research in humans is required.
Improves insulin resistance
Insulin resistance is a central feature in people living with PCOS. Many people with PCOS have insulin resistance, regardless of body weight. Insulin resistance is associated with androgen overproduction, ovulatory dysfunction and metabolic complications.
In a rodent study, 96 rats with oestradiol valerate-induced PCOS were given different doses of green tea extract (or no supplement) for 10 days. The study found that insulin resistance was decreased in the rats who were given green tea. Of course, as this is an animal study, more evidence in human PCOS patients is required.
A double-blind randomised clinical trial of 60 people with PCOS divided participants into two groups with one group receiving green tea and the other receiving a placebo. They found that after the 12-week trial period, there was a significant reduction in the fasting insulin levels in people taking the green tea.
Improves testosterone levels
PCOS is associated with elevated levels of androgens (male sex hormones) such as testosterone. High levels of testosterone are linked to PCOS symptoms like oily skin, acne, excessive hair growth across the body, hair loss on the head and more. Plus, hyperandrogenism is associated with menstrual irregularity (irregular periods) and fertility issues.
A systematic review of four animal studies and four human studies evaluated the benefits of green tea extract on various markers. This study found that green tea extract in PCOS animal studies decreased testosterone levels, as well as decreased LH, increased FSH and progesterone levels suggesting a potential role in regulating hormone balance.
The double-blind randomised trial mentioned above looking at the effect of green tea vs placebo on people with PCOS also found beneficial effects on testosterone levels. They found that 12 weeks of supplementation improved free testosterone levels.
How much green tea do you need to drink?
The studies we’ve analysed do not provide a uniform dosage of green tea for PCOS symptoms. This is because different studies use different forms of green tea (such as tablets or extracts) and because some studies do not provide the dosage at all.
If you choose to drink green tea, try drinking a couple of cups of green tea per day but, unfortunately, we cannot be conclusive on dosage for PCOS.
Can I take a green tea supplement instead?
Green tea supplements made with green tea extract do tend to more closely mimic the green tea administered in the studies we’ve mentioned. But, the quality of evidence isn’t high enough to conclusively recommend green tea supplements for PCOS management.
People with PCOS often feel like they need to take many supplements to manage their condition but green tea supplements aren’t one of them. Read more about the best supplements for PCOS in our dedicated article.
What about the caffeine in green tea?
Green tea does contain caffeine and a standard cup typically contains less than black tea or coffee. On average, a 237ml cup of green tea contains between 25-50 milligrams of caffeine but the caffeine content in green tea can vary depending on the type of green tea, how it is processed and how it is brewed.
Caffeine isn’t inherently bad for PCOS. But if you are noticing that you are drinking more caffeinated drinks than anything else, then you may want to look a little closer at your intake. This is because caffeine keeps us alert and awake which can impact our sleep. People with PCOS often have sleep issues like sleep apnea or insomnia which may be impacted by caffeine intake.
Be aware of your caffeine intake and mindful that if your consumption is impacting your symptoms of PCOS, you may want to lay off the green tea.
Side effects of green tea consumption
Green tea is consumed regularly all over the world and is generally considered safe for most adults when consumed in moderate amounts. But, as with anything, consuming too much green tea may have side effects.
These may include:
- Sensitivity to caffeine: it is important to remember that green tea does contain caffeine. This may impact sleep and cause insomnia, anxiety or irritability. Be aware of your own caffeine tolerance.
- Iron absorption issues: the tannins in green tea can bind to iron which can make it difficult for the body to absorb non-heme iron (iron found in plant-based foods) which could lead to iron deficiency. Avoid drinking green tea whilst consuming iron-rich plant-based foods like green leafy vegetables to maximise iron absorption.
- Gastrointestinal upsets: green tea may exacerbate stomach upsets or constipation because of the tannins which can increase stomach acidity.
- Reduced bone health: there is some evidence that high consumption of green tea may lead to decreased bone density which could increase the risk of osteoporosis, particularly in people with low calcium intake.
- Interactions with medications: green tea could interact with certain medications such as blood thinners, blood pressure medications and other stimulants. As always, if you are taking medication always consult your healthcare professional before changing your diet or supplement regime.
- Concerns about liver health: green tea in high doses may contribute to liver damage, particularly in those taking high-dosage supplements.
People who are pregnant or are currently breastfeeding should avoid consuming green tea because of the caffeine content. Too much caffeine during pregnancy could increase the risk of miscarriage and affect foetal development.
Best green tea for PCOS
Although there is no one best green tea for PCOS we have rounded up just a few of our favourite-tasting green teas.
Key takeaways: Is green tea good for PCOS?
The research on green tea for PCOS is promising with potential benefits for inflammation, insulin resistance and testosterone levels. But, the majority of the research is done in animals and the human research isn’t of a high enough quality or conclusive enough to recommend green tea for PCOS definitively. But, if green tea is something you enjoy then drinking a couple of cups per day is a low-risk, low-cost PCOS intervention.
There are many other types of tea associated with PCOS including spearmint tea, ginger tea, chamomile tea, cinnamon tea and raspberry leaf tea. Head to our best PCOS teas article to read more about the health benefits of tea for PCOS.
Founder and Editor | Registered Associate Nutritionist
Founder of Be The Collective LTD [The PCOS Collective & The Endo Collective] Alex Okell ANutr is a London-based reproductive health nutritionist with experience in research, private practice and digital media. She holds a Master’s degree in Nutrition from King’s College London and has co-authored papers with the University of Cambridge, King’s College London, The Food Foundation and the Food Standards Agency. Alex offers 1:1 PCOS support in our virtual PCOS clinic.