Does Coffee Disrupt Our Hormones?

Written by Maeve Hanan

You may have heard the recent claims on TikTok that drinking coffee can play havoc with your hormones.

This message was spread by a number of wellness influencers, and alternative ‘functional nutritional therapists’ and ‘nutritional practitioners’. They claimed that drinking coffee first thing in the morning on an empty stomach leads to dysregulated cortisol which in turn can cause things like acne, painful periods, gut issues, hair loss, anxiety and ‘thyroid imbalance’.

Let’s take a closer look at this from an evidence-based perspective.

How does cortisol impact health?

Cortisol is often called ‘the stress hormone’ as the body releases this in response to stress to trigger the ‘fight or flight’ response. Cortisol also plays an important role when it comes to our metabolism, body clock, inflammation and regulating blood glucose and blood pressure levels.

Although cortisol is needed by the body, chronically (i.e. over a long period of time)  high levels can be harmful for the cardiovascular, immune, nervous, reproductive and endocrine systems (1, 2). This could increase the risk of conditions like diabetes and heart disease (3).

Stress can impact the risk of acne, PMS, gut issues, anxiety, hair loss and thyroid function (4, 5, 6, 7). But the claims that these issues are a direct result of high cortisol due to drinking coffee in the morning is overly simplistic and not backed by research.

Caffeine and Cortisol

A few studies have found that consuming caffeine can increase cortisol levels in the short term (i.e. often for 1-2 hours) (8, 9, 10). This may be due to caffeine interacting with metabolism and/or the nervous system (8).

But not all studies have found this to be the case, and one study found that caffeine people needed to be stressed out already for cortisol levels to increase in response to coffee (11).

Interestingly, a study from 2008 found cortisol response seems to be reduced in those who consume caffeine regularly, as they built up a tolerance to this (9).

Cortisol levels peak in the morning, around 30 to 45 minutes after waking up (12). So consuming coffee at this time could lead to higher levels of this hormone.

But it isn’t clear whether drinking coffee on an empty stomach makes a difference to cortisol levels. And no long-term studies have investigated whether increased cortisol related to drinking coffee impacts our health.

Caffeine and reproductive hormones

What about the claims that caffeine messes up your sex hormones?

Some studies have found that a higher intake of caffeine is linked with lower oestrogen, lower testosterone and higher progesterone levels (13, 14, 15, 16).

But this evidence base is sparse overall and it isn’t currently clear whether this has a significant impact for most people. This could also vary a lot between different people based on their biology, caffeine tolerance, stage of menstrual cycle etc.

Cortisol can suppress the ​​hypothalamic-pituitary-adrenal (HPA) axis (the connection between the brain and adrenal glands which plays a major role in hormone regulation) (17). So theoretically this could impact reproductive hormones, but this isn’t currently backed up by the evidence base.

There’s mixed evidence about whether caffeine impacts menstrual cycle outcomes. For example, a study of university students from 2014 found coffee consumption to be a risk factor for prolonged and irregular periods (18). Whereas an older study from the 90s found heavy caffeine consumption (more than 300 mg of caffeine per day) was linked with reduced likelihood of having prolonged periods, and doubled the risk of a short menstrual cycle of 24 days or less (19).

The 2014 study also found that nescafe in particular was associated with heavy periods and menstrual symptoms, while a study from the prospective Nurses' Health Study II found that caffeine intake wasn’t linked with menstrual symptoms (18, 20).

There are also some conflicting findings about the impact of caffeine on female fertility outcomes, but as a precaution it is usually recommended to limit caffeine to 200mg per day or less (the recommended limit during pregnancy) when trying to conceive (21,22).

Indirectly, one real life damaging impact of caffeine intake on female hormones is when this is used as an appetite suppressant, as not consuming enough energy can lead to hormonal issues  and an irregular or missing period (23​​).

What impact can your morning coffee have?

A morning coffee has many benefits for a lot of people, including increasing alertness, stimulating the bowels and reducing constipation. The antioxidants found in coffee have also been seen to have a number of health benefits and may contribute to a lower risk of certain diseases like heart disease and diabetes (13, 14). And don’t forget that coffee counts towards your fluid intake for the day.

However, depending on the amount consumed and your individual tolerance level, you can experience negative side effects from the caffeine in coffee such as jitters, anxiety, heart palpitations and gut issues like diarrhoea. There’s conflicting advice and evidence about whether caffeine intake influences PMS, but overall this doesn’t seem to be a very significant factor (15).

The timing of your morning coffee can be important under certain circumstances. For example, drinking coffee on an empty stomach may worsen reflux for some people (​​16). This could be related to an increase in stomach acid and relaxing the sphincter at the bottom of the oesophagus. But there isn’t strong evidence to avoid coffee, either in general or on an empty stomach, when it comes to reflux (17, 18).

Delaying your coffee intake until too late in the day could have a negative impact on your sleep. This is because the alertness we get from caffeine can last for 6 to 16 hours (19, 20).

Your morning coffee might also impact the iron you absorb from your breakfast, as antioxidants called tannins found in coffee block iron absorption. So to avoid this, it’s recommended to leave an hour between coffee and iron-containing meals.

Although there isn’t strong evidence related to caffeine and thyroid function, it can interfere with the absorption of a thyroid medication called levothyroxine. So it’s advised to take this medication at least 30 minutes before having caffeine-containing drinks like coffee (21).

For more information about the health impact of coffee, checkout this article The Pros and Cons of Coffee.

Summary

The claims that drinking coffee on an empty stomach ‘disrupts hormones’ and directly leads to specific side effects like acne and hair loss are over the top.

Our cortisol levels are raised in the morning and drinking coffee may increase cortisol further. But the jury is still out on this, and you may be able to build up a tolerance which reduces this possible response. It also isn’t clear whether drinking coffee on an empty stomach influences cortisol levels, and whether this makes a difference to our health, especially in the long-run.

Although it’s unlikely to lead to any dramatic changes, for most people there is little harm in trying out drinking coffee with or after breakfast to see if it makes any difference for you. However, be aware that having coffee with breakfast may reduce iron absorption from the meal and leaving it too late may worsen your sleep that night. So the sweet spot might be to have your coffee mid-morning, if you can wait that long!