Caffeine and PCOS: is drinking tea and coffee bad for PCOS?

Brewing your favourite tea or having a good cup of coffee tends to be a common morning ritual most of us share. What can be a controversial topic is whether caffeine affects conditions like PCOS, especially if you are trying to get pregnant. Let’s take a closer look at caffeine and PCOS and investigate the scientific research.

What is PCOS?

Polycystic ovarian syndrome or polycystic ovary syndrome (PCOS) is a complex endocrine (hormone) condition impacting 1 in 10 people assigned female at birth (AFAB). Despite its name, it does not solely involve the ovaries.

Common symptoms of PCOS experience include but are not limited to irregular periods, infertility, acne, excess facial and/or body hair, loss of hair and hidradenitis suppurativa skin tags.

As PCOS cannot be cured management of the condition often involves lifestyle changes regarding nutrition. So, can caffeine make a difference in PCOS symptoms?

What is caffeine?

Caffeine is a natural stimulant found in the seeds, fruit and leaves of a plant. It belongs to a class of compounds called xanthines and is present in tea, coffee, and cacao plants.

Caffeine directly acts upon the central nervous system and has many different effects including increasing alertness, increasing the heart rate, improving mood, and enhancing physical and cognitive function. Each person can have a different tolerance level to caffeine and too much caffeine may have negative effects.

What foods and drinks contain caffeine?

Caffeine can be found in many foods and drinks. Some common sources of caffeine include:

  1. Coffee – coffee beans are the most common source of caffeine. The amount of caffeine in coffee depends on the type of bean used, the brewing method and serving size.
  2. Tea – tea leaves contain caffeine. The caffeine content in tea is usually lower than in coffee. Not all teas contain caffeine but green tea, black tea, white tea and oolong tea all contain caffeine.
  3. Carbonated soft drinks – cola drinks in particular are known for their caffeine content.
  4. Energy drinks – as the name suggests, energy drinks like Monster or Red Bull contain caffeine and other stimulants to boost energy levels and alertness.
  5. Chocolate – cacao beans which are used to make chocolate bars, cocoa and hot chocolate contain caffeine. Dark chocolate contains more caffeine than white chocolate.
  6. Medications – some medications may include caffeine to increase alertness.
  7. Energy gels – energy gels often used by athletes contain caffeine to boost their effectiveness.

​Caffeine amounts in different foods and drinks

Of course, caffeine amounts vary with different factors like serving sizes and production methods but here is a simple guide for the amount of caffeine in 9 different foods and drinks:

  1. A cup of instant coffee (8 oz): Approximately 63 mg
  2. A cup of filter coffee (8 oz): The caffeine content can range from 95 to 165 mg or more, depending on the coffee bean type, roast, and brewing method.
  3. An espresso shot (1 oz): Approximately 63 mg
  4. A regular latte (8 oz): The caffeine content in a latte depends on the type of coffee used and can vary. It’s typically similar to a cup of filter coffee, ranging from 95 to 165 mg or more.
  5. A mug of black tea (8 oz): Approximately 40-70 mg, but this can vary based on the tea variety, steeping time, and strength.
  6. A mug of green tea (8 oz): Approximately 20-45 mg, but like black tea, it can vary based on the type of green tea and how it’s prepared.
  7. A can of energy drink (12 oz): The caffeine content in energy drinks can vary widely, but a typical energy drink contains around 70-200 mg or more of caffeine. Some brands may have even higher caffeine content.
  8. A milk chocolate bar (1.55 oz): Approximately 9-15 mg, but this can vary based on the brand and cocoa content.
  9. A dark chocolate bar (1.55 oz): Dark chocolate generally contains more caffeine than milk chocolate. It can vary from 12-20 mg or more, depending on the cocoa content and brand.

Being aware of which foods and drinks have high caffeine levels may be helpful to understand your personal caffeine intake and tolerance.

Is there a link between caffeine and PCOS?

The link between PCOS and caffeine has been hotly debated. Let’s take a look at the evidence to understand the effects of caffeine on people with PCOS.

​May reduce inflammation

People with PCOS often have chronic inflammation which is believed to be a driver of the syndrome.

2022 study investigating caffeine in PCOS in rat models found a potential link between caffeine intake and the reduction of inflammation. However, further human studies are needed.

Conflicting evidence on insulin resistance

Many of the symptoms related to PCOS are due to high hormone levels such as androgens and insulin. Insulin is a hormone which helps the body use glucose (sugar) from food. Up to 80% of people with PCOS are insulin resistant and consequently have more insulin in their blood than normal.

There is some evidence that coffee consumption may help to manage blood sugar levels although other studies suggest that caffeine impacts blood glucose levels negatively in people with type 2 diabetes. A meta-analysis found that long-term coffee consumption had non-significant effects on insulin resistance and sensitivity. 

More dedicated studies focused on PCOS patients are required to understand the impact of caffeine on insulin sensitivity and blood glucose levels in people with PCOS.

May increase cortisol levels

People with PCOS tend to have adrenal glands (located on top of the kidneys) overproducing hormones like cortisol (a major stress hormone). Cortisol has an impact on PCOS as it impacts other hormones throughout the body including insulin and female sex hormones like FSH and LH.

Caffeine may increase the production of cortisol, therefore it may be advised to minimise or avoid caffeine during stressful times to avoid extra cortisol spikes which may, in turn, impact symptoms of PCOS.

>> Learn more | Debunking PCOS adrenal fatigue and adrenal PCOS

May impact sleep

Caffeine can also remain in our body’s system for over 5 hours after drinking, as its half-life is about 5 hours. This means if your last caffeinated drink was at 5 p.m., by the time you’re trying to go to sleep it could still be keeping you alert. 

Poor quality sleep is linked to changes in hunger hormones, which can then in turn worsen carbohydrate cravings (already very prevalent in people with PCOS). This is because when we are sleep-deprived we are looking for quick-acting energy-releasing foods. The following day this often leads to the consumption of more caffeine to keep us alert and awake and so the cycle continues.

Sleep disorders, such as sleep apnoea are found to be more likely in PCOS. While caffeine promises instant wakefulness, moderation is key to avoiding potential sleep disturbances. If you are suffering from sleep apnoea, insomnia or PCOS fatigue then speak with a healthcare professional to get the support you require.

Conflicting evidence on fertility outcomes

Caffeine and fertility is a highly controversial and disputed topic. But recent studies including a 2020 systematic review, found that there is no evidence to suggest that caffeine-containing foods and drinks are associated with fertility issues. In people living with PCOS, infertility is likely to occur because of hormonal imbalances that result in a lack of ovulation. Focusing on repairing your cycle and regaining regular ovulation is key to improving fertility outcomes.

>> Read More | PCOS and Fertility: the ultimate guide to conception

​How much caffeine should I have?

Since caffeine acts as a stimulant, excessive intake or consumption of caffeinated beverages close to bedtime might negatively affect sleep. Recognising your personal caffeine threshold and avoiding coffee near sleeping hours can potentially aid in addressing sleep disturbances.

The general guideline regarding caffeine daily intake is to stay below the recommended 400 mg of caffeine per day. On average a cup of black tea (220 ml) contains 50 mg of caffeine and a large cup of filter coffee contains 180 mg of caffeine, however, this can differ. 

During pregnancy, the British Dietetic Association recommends no more than 200 mg of caffeine daily, which is about 2 mugs of instant coffee (or one mug of filter coffee) or 3 mugs of tea a day. 

If you are trying to conceive the general guidance concurs that if you consume a high amount of caffeine, begin gradually reducing your intake to within the recommended limits.  

How to reduce caffeine intake

If you find that caffeine doesn’t impact you positively and think you may want to reduce your caffeine consumption then there are some easy changes you can make to lower your intake.

1. Switch to decaf coffee and tea: instead of your usual caffeinated cup why not switch to a decaffeinated coffee or tea instead? The flavour of decaf drinks is often as delicious as the real deal now.

2. Change to a naturally caffeine-free option: you could try switching your usual coffee for a chicory coffee, golden turmeric milk or herbal tea.

3. Have your last caffeinated drink earlier: if your cups of coffee are impacting your sleep then try having your final caffeinated beverage earlier in the day.

Key takeaways: PCOS and caffeine

In conclusion, do you need to be thinking about your caffeine intake? If you are noticing that you are drinking more caffeinated drinks than anything else, then the answer may be, Yes. Caffeine can keep us in a cycle of sleep deprivation and trying to stay awake so if you want to improve your sleep hygiene it may be looking at your last caffeinated beverage of the day and moving it earlier in the day. You may find getting more sleep will help manage your PCOS symptoms. 

Sophia Boothby RD Author at The PCOS Collective

Lead Author | Head Dietitian | Registered Dietitian


Sophia is a Registered Dietitian working as a Specialist Community Dietitian within a London NHS Teaching Hospital specialising in gut health such as irritable bowel syndrome (IBS) and the low FODMAP diet, type 2 diabetes, PCOS, and cardiac rehabilitation. Sophia offers 1:1 PCOS support in our virtual PCOS clinic.

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