Coffee definitely impacts your cycle. But why? To what extent? Do the effects vary depending on the person? 

I hope to clear up all these questions for you today. 

Let’s start here…

What is caffeine and how does it affect your body? 

Caffeine is a xanthine alkaloid found naturally in coffee beans, tea, kola nuts, Yerba mate, guarana berries, and cacao beans. 

Caffeine stimulates your central nervous system–we’ll get to that in a moment!

When you have a cup of coffee, you cue a hormonal cascade.  

First, the brain makes a substance called adenosine, which is used in the production of adenosine triphosphate or ATP. 

As you may know, ATP is like the energy currency of the cells. It carries energy between the cells of all living things so different tasks and processes can be performed by the body. 

ATP then breaks back down into adenosine. The more brain activity we have during the waking hours, the more adenosine we produce. And as adenosine levels build up, we become drowsier, which is basically the signal from the body to get some sleep and rebuild our energy stores. While we sleep, adenosine levels gradually decline, which eventually leads us to wake up again.

Got all that? Good! Here is where caffeine comes in…

Caffeine works by blocking adenosine receptors on your cells. It just parks in the adenosine receptor parking space, preventing adenosine from parking in its own receptor.

Subsequently, adenosine is building up but it’s not able to send the signal to the body because it can’t get into its cell receptor parking space!

This prevents us from having those feelings of drowsiness when adenosine builds up.

Caffeine and the Nervous System

With caffeine in your system, your adrenal glands activate and release the stress hormone adrenaline (epinephrine) which causes you to enter a “fight or flight” state. [1]

With the sympathetic nervous system activated, this can include a quickening pulse, tense muscles, increased heart rate and alertness – necessary physiological changes for the body to get up and sprint from a tiger. 

Blood pressure increases, and your heart is working to deliver more oxygen to your brain and shift glucose into your blood circulation to boost energy. 

So essentially coffee / caffeine stresses your body. Which is ironic since so many people go for another cup when they are tired and stressed.  

Caffeine can also indirectly cause the release of dopamine [2], the feel-good pleasure hormone. This is one of the reasons coffee and other caffeinated beverages become addictive for many people. 

What does this have to do with the menstrual cycle? 

When your body is in this fight or flight state, there is increased blood flow to your muscles (so you can run) and decreased blood flow to “non-essential” organs, like the ovaries and your digestive system. 

If your body is constantly in this activated, sympathetic nervous system mode, it doesn’t consider itself to be a safe space to grow a human, and fertility can become impaired. 

This is due to the fact that your adrenals and ovaries are connected, and the adrenals have a direct effect on ovarian function/menstrual cycles/fertility.

Please read this blog post to understand how this works in your body

This also has to do with blood sugar balance. Chronically high blood sugar leads to chronically high insulin.

Insulin has a downstream effect on your ovaries and their production of your key sex hormones estrogen, progesterone and testosterone. 

As mentioned above, the release of adrenaline cues the release of glucose via the liver. This causes the pancreas to start secreting extra insulin to help usher the glucose into the bloodstream for your body’s cells to then use as energy. 

Here’s the thing. Hormone balance relies on blood sugar balance. If your blood sugar is not stable, and it’s constantly spiking from caffeine (in addition to all your other stress), well, hello period problems. 

To further complicate things, caffeine can actually decrease insulin sensitivity, which can lead to insulin resistance. [3]

But I still want to continue drinking coffee!

Many of my clients over the years have begged me not to make them give up coffee. I get it! Life is A LOT and coffee helps a lot of us function.

So, if you are determined to continue drinking coffee, please at least just take this one piece of advice: 

Breakfast (or any meal or high protein snack for that matter!) before coffee. 

Drinking coffee, or any caffeine, first thing on an empty stomach is incredibly problematic and is  only going to exacerbate the glucose spike and adrenal stress response, setting you up for issues the rest of the day (afternoon crash anyone? Sleep issues at night?). 

Why does caffeine cause sleep issues?

Speaking of sleep issues at night. Remember what I said about adenosine earlier in this article?

The accumulation of adenosine in the body is connected to the amount of caffeine consumed throughout the day! Yikes! 

High caffeine intake leads to higher adenosine levels, and oftentimes leads to adenosine not being adequately cleared from the body during sleep.

Guess what happens next?

Yup, these high adenosine levels cause you to wake up feeling drowsy or groggy in the morning. Then you resort to coffee to wake you up!

As you can imagine, this is a vicious cycle that leads to worse and worse sleep, you feeling more and more tired in the morning and needing more and more caffeine. 

Why does a half cup of coffee make me twitch and my friend can have 3 cups?

Due to genetics and diet & lifestyle choices, coffee affects people differently. 

Caffeine is metabolized by an enzyme in the liver that is encoded by what’s known as the CYP1A2 gene. 

About 50% of the population has a variant in the CYP1A2 gene that leads to the slow metabolism of caffeine. [4]

Fast caffeine metabolizers take between 4-6 hours to lower caffeine levels by half. Slow caffeine metabolizers take between 8-10 hours to drop caffeine levels by half.

Slower metabolizers have an increased sensitivity to and lower tolerance for the effects of caffeine. I happen to be a sloooowwww metabolizer, so I max out at one cup of black tea and I better have it with food or I’m in trouble LOL!

Non-genetic factors can also influence the way caffeine is metabolized, such as oral contraceptive use (the pill slows metabolism of caffeine), diet, alcohol and pregnancy. [5]

Other things to consider

The over-consumption of coffee can lead to mood issues like anxiety, nervousness and sleep disturbance [6], which may only be exacerbated if you already experience premenstrual symptoms. 

If not consumed in moderation, caffeine can interfere with nutrient absorption of essential vitamins and minerals, including calcium, iron, magnesium, B-vitamins, and vitamin-D [7], all of which are essential for a healthy menstrual cycle. 

Slow caffeine metabolizers are at higher risk for heart disease, hypertension and impaired fasting glucose levels. [8]

Caffeine may worsen the pain and soreness that is associated with fibrocystic breast tissue. [9]

In a recent meta analysis that included 26 studies, coffee and caffeine consumption during pregnancy appears to increase the likelihood of pregnancy loss. [10]

You may want to consider reducing or eliminating caffeine as evidence shows that, in addition to spontaneous abortion (miscarriage / pregnancy loss), greater intake appears to be associated with an increase in stillbirth, low birth weight, and SGA (small for gestational age). [11]

If you decide to quit coffee, know that withdrawal symptoms may include: fatigue, headache, irritability, anxiety, brain fog, low mood and poor concentration. Symptoms generally begin to resolve after 2-3 days. 

The benefits of coffee – it’s not all bad

I actually hate the taste of coffee and have never drank it, but I know that I am in the minority! The good news is that if you’re going to drink it, there are some potential benefits, again depending on your genetics and lifestyle.

Coffee may be neuroprotective 

As mentioned above, caffeine interacts with the dopaminergic system. Animal models have shown that because of this, caffeine may lead to improvements in symptoms of depression and attention deficit hyperactivity disorder (ADHD). Caffeine has also been found to modulate GABA receptors and suppress inhibitory (GABAergic) activity. [12] GABA (Gamma-aminobutyric acid) is an essential neurotransmitter that has a protective and calming effect on the brain and body. 

Several studies have shown the potential association between caffeine intake and reduced risk of Parkinson’s Disease, in both fast and slow caffeine metabolizers, revealing that caffeine and its major metabolite, paraxanthine, are neuroprotective.

Related to this is a study showing a reduced suicide risk. The Harvard study revealed a 50% reduction in risk among both men and women who were moderate coffee drinkers, perhaps by boosting production of brain chemicals that have antidepressant effects. [14]

Additional research shows caffeine may reduce the risk of multiple ailments including heart disease, Type 2 diabetes, gallstones, cirrhosis, liver cancer, melanoma and prostate cancer. [15]

A recent comprehensive study highlighted by the New York Times revealed that moderate consumption of unsweetened and sugar-sweetened coffee was associated with a lower risk for death. [16]

“Those who drank 1.5 to 3.5 cups of coffee per day, even with a teaspoon of sugar, were up to 30 percent less likely to die during the study period than those who didn’t drink coffee. Those who drank unsweetened coffee were 16 to 21 percent less likely to die during the study period, with those drinking about three cups per day having the lowest risk of death when compared with non-coffee drinkers.

There are, however, major caveats to interpreting this research… 

“This is an observational study, which means the data cannot conclusively prove that coffee itself lowers the risk of dying; there may be other lifestyle factors contributing to that lower mortality risk among people who drink coffee, like a healthy diet or a consistent exercise routine.” – NYT

Antioxidants may be the key 

More research is needed to understand why coffee may be so beneficial for some, but the answer may lie in its antioxidant properties. Antioxidants can prevent or delay cell damage, and coffee beans do contain high amounts of antioxidants. Over time, a buildup of free radicals can increase inflammation in the body, which can lead to heart disease and other conditions, so consuming foods and beverages that are rich in antioxidants can be protective. 

What about green tea?

You may have heard about the incredible benefits of green tea, and matcha in particular. The rumors are true! However, everything I’ve said above regarding caffeine applies to green tea (and all teas) as well. Caffeine is caffeine. 

Here are the main differences between green tea and coffee, and the benefits of green tea that may make it more beneficial than coffee. [17]

Coffee provides more than three times the amount of caffeine than green tea. An 8 oz (240 mL) serving of coffee provides 96 mg of caffeine, while the same amount of green tea provides 29 mg. [18]

Green tea is loaded with antioxidants — compounds with beneficial effects against oxidative stress, as mentioned above. Matcha green tea is particularly rich in a group of antioxidants called polyphenols. [19]

Epigallocatechin gallate (EGCG) – found in green tea – and chlorogenic acid (CGA) – found in coffee – are the most abundant polyphenols. 

Human studies still present inconsistent results, however EGCG’s anti-inflammatory effect may help prevent the chronic inflammation involved in the onset of cancer. This has been demonstrated in cell based and animal studies. [20]

Perhaps one of the key benefits of green tea over coffee is L-theanine, an amino acid naturally present in green tea. This magical compound is known to affect the brain, increasing feelings of calm alertness. [21]

Now before you go and drink a matcha latte every day, remember that a latte consists of a large serving of milk or non-dairy milk. Choose wisely, as most oat milks and many other non-dairy alternatives contain processed seed oils that are inflammatory. I’m not a matcha person (am I the only person who thinks it tastes like dirt?? Haha!), but when it comes to milks I recommend full fat coconut, homemade nut milks or organic/grass fed whole milk. 

More Coffee Replacements

Adrenal cocktail

I LOVE an easy homemade adrenal cocktail. You can read all about why the sodium-potassium balance is so important in the body, and why this bev is a go-to choice instead of coffee for me here in this IG post.

Don’t want to make it yourself? Try this adrenal cocktail powder supplement by Jigsaw Health – it’s another favorite of mine.

Bone Broth 

Bone broth is a mineral-rich infusion made by boiling bones of healthy animals with vegetables, herbs and spices.  It has been used for centuries in many traditional cultures as a healing, and fertility-enhancing food.

Bone broth is incredibly healing for your gut and hormones!

Head over to this blog post of mine to read all about it. 

Four Sigmatic 

A cool company with yummy mushroom and adaptogen based coffee alternative products. Check it out here!


Another coffee alternative filled with adaptogens and organic ingredients. It’s a blend of cacao, chai, chaga, reishi, lion’s mane & more. It does have a bit of caffeine in it from the chai tea, but about 1/7th the amount of coffee: 32mg of caffeine per 6g serving when mixed with 12 oz of water.

Dandy Blend

Made from the water soluble extracts of barley, rye, chicory roots, beet roots, and dandelion roots. Has the consistency of instant coffee and can be served hot, cold, or in your favorite recipe. Simply add water and stir. Check it out!


A quick note about decaf. If you’re going to drink decaf coffee, know that the process to remove the caffeine can often include toxic ingredients. Opt for a brand that’s certified organic and solvent free.

There you have it! Now you’ve got all the juicy info you need to make an informed decision about whether to drink the caffeine or not drink the caffeine. If you enjoyed reading this, please share with a friend and feel free to leave a comment with your experience!