Most people have feelings about coffee.
Some people can’t live without it and go to bed at night looking forward to their morning cup. While others just don’t feel the same love for it.
Does it spike cortisol? Is it good or bad for my gut health? And what about caffeine jitters?
We can’t talk about coffee without talking about caffeine, and even if coffee isn’t your thing, caffeine often still finds its way in through energy drinks, soda, or other sources. raising the same question: “Is this good for me?” As with everything, it’s truly personal, so we’re sharing insights on both coffee and caffeine to help you make an informed decision.
Why caffeine makes us feel like we can take on the world (or at least those boring, monotonous tasks that need to get done)…
The science-y answer is that caffeine blocks adenosine, a chemical in your brain that makes you feel sleepy. When that signal is muted, you feel more alert, less fatigued, and a little more ready to tackle your day.
It can also sharpen focus, improve reaction time, and even enhance how well certain pain medications work. So yes, caffeine can absolutely help you “do the things.”
Ok, so caffeine helps me do the things… but is it good for my health?
Like most things, it’s nuanced. When we look at the research, the effects of caffeine really come down to how much and how often. Moderate intake—about 3 to 5 cups of coffee per day, or up to 400 mg of caffeine—is consistently linked with a range of fabulous health benefits:
- Lower risk of heart disease, stroke, and cardiovascular-related death
- Reduced risk of type 2 diabetes
- Protection against liver disease, including cirrhosis and liver cancer
- Lower risk of certain cancers, including endometrial cancer
- A strong association with reduced risk of Parkinson’s disease
- Lower rates of depression and suicide
- Overall, a longer lifespan
Does that mean more is better?
No. Once intake creeps above about 400 mg per day, the benefits tend to level off—and for many people, side effects start to show up:
- Anxiety, restlessness, or feeling “on edge.”
- Trouble sleeping
- Racing thoughts or feeling unable to slow down
- Increased heart rate or palpitations
- More frequent urination
Large amounts in a short period of time (think energy drinks or multiple strong coffees close together) can also put extra strain on the cardiovascular system, especially in people who are more sensitive or not habitual caffeine drinkers.
Habitual vs Infrequent Coffee Drinkers
People who don’t usually drink coffee may notice short-term effects like a temporary rise in blood pressure or changes in blood sugar regulation. With consistent intake, these responses tend to lessen over time. Research suggests this is partly because the body adapts to caffeine’s effects on the nervous system, including how it influences signals that regulate alertness and cardiovascular response. Even the familiar caffeine “boost” may feel less noticeable over time.
Coffee is more than just caffeine
Coffee isn’t just a caffeine delivery system. It also contains a range of bioactive compounds, including polyphenols, antioxidants, and other plant compounds that may contribute to health.
Research suggests these compounds may:
- Support blood sugar regulation and metabolic health (though effects vary by individual and context)
- Help reduce oxidative stress in the body
- Be associated with improved liver health and lower risk of fatty liver disease
- Support a more favorable gut microbiome environment
Many of these benefits are observed with decaffeinated coffee, suggesting that compounds beyond caffeine play an important role.
What you put in your coffee matters
Though we see health benefits from moderate coffee consumption, we can’t ignore the coffee additions that can diminish these benefits.
Small additions like a splash of half and half or a modest amount of milk tend to have minimal impact on blood sugar, but larger amounts of sugar, flavored syrups, and sweetened creamers can quickly turn a simple cup of coffee into something that behaves more like a sugar-sweetened beverage in the body. Research consistently shows that added sugars increase blood glucose and insulin demand, and over time, can weaken many of the protective associations seen with coffee alone.
The takeaway is not that you need to drink coffee black, but rather that there is a meaningful difference between a lightly personalized cup of coffee and one that is essentially a dessert in a mug. Choosing simple, less processed additions more often helps preserve the natural benefits coffee can offer while still keeping your routine enjoyable and realistic.
Why caffeine affects everyone differently
Your response to caffeine can vary based on genetics, metabolism, medications, and even lifestyle factors like smoking.
Caffeine is mainly broken down in the liver by an enzyme called CYP1A2. How active that enzyme is in your body determines how quickly caffeine is cleared—and that can vary quite a bit from person to person.
Here are a few situations where caffeine tends to stick around longer:
Pregnancy
During pregnancy, caffeine metabolism slows significantly—especially in the second and third trimesters. This means caffeine stays in your bloodstream much longer than usual. Since it also crosses the placenta and the baby has a very limited ability to break it down, higher circulating levels can build up. That’s why recommendations are more conservative (generally ≤200 mg per day).
Birth control (oral contraceptives)
Estrogen-containing birth control can slow down the activity of the CYP1A2 enzyme. Practically speaking, this means caffeine lasts longer in your system, and you may feel its effects more strongly—or for a longer period of time—compared to when you’re not on it.
Quitting smoking
Smoking actually speeds up caffeine metabolism by increasing CYP1A2 activity. So when someone quits smoking, their caffeine clearance slows back down to baseline. If caffeine intake stays the same, it can suddenly feel like “too much”—leading to jitteriness, anxiety, or trouble sleeping. This is an often-overlooked adjustment during that transition.
Genetics (slow vs. fast metabolizers)
Some people naturally have a slower version of the CYP1A2 enzyme due to genetic variation. These “slow metabolizers” break down caffeine more gradually, meaning it stays active in the body longer. Research suggests they may be more sensitive to the negative effects of higher caffeine intake, particularly when it comes to blood pressure and cardiovascular risk.
On the flip side, “fast metabolizers” clear caffeine more quickly and may tolerate moderate intake with fewer noticeable side effects.
Coffee and sleep
Because how long caffeine stays active in your body varies from person to person, not surprisingly, caffeine doesn’t affect everyone’s sleep in the same way.
Especially if you are a slow caffeine metabolizer, caffeine can still be active in your system hours later and may subtly affect sleep quality, including how easily you fall asleep and how restorative your sleep feels.
If sleep has been a concern, one of the simplest strategies to experiment with is adjusting the timing of your last caffeine intake to earlier in the day.
Coffee and gut health
Coffee can play a supportive role in gut health. Both regular and decaf coffee contain polyphenols that act as fuel for beneficial gut bacteria, helping increase microbial diversity and the production of short-chain fatty acids linked to metabolic and immune health.
At the same time, coffee stimulates the digestive tract. It increases gastric acid production and promotes movement in the intestines, which is why many people notice a bowel movement shortly after drinking it. For individuals with GERD, this increase in acid can worsen reflux symptoms, and for those with IBS-D, the stimulation of gut motility can lead to urgency or looser stools.
While coffee can support gut health at a microbiome level, symptom response matters. If you have a sensitive digestive system, experimenting with timing, amount, or even switching to decaf may help you find a balance that supports both your gut bacteria and your day-to-day comfort.
Coffee and cortisol
Caffeine can cause a short-term increase in cortisol, a hormone involved in alertness and energy regulation. There is a popular claim that coffee on an empty stomach or it too soon after waking meaningfully disrupts cortisol rhythms. Current evidence does not support this for healthy individuals.
Cortisol naturally peaks in the morning as part of your circadian rhythm, whether you drink coffee or not. Adding caffeine during this window may slightly increase that rise, but studies show the body adapts in regular coffee drinkers, and these changes are not considered clinically significant in healthy adults.
Where it does get more individual is how you feel. If you are already waking up feeling wired, anxious, or stressed, caffeine can layer on top of that and amplify those sensations. In that case, it may be worth experimenting with delaying or reducing your first cup. But if you wake up feeling steady and energized, there is no strong evidence that you need to avoid coffee in the morning or wait a specific amount of time.
Bottom line: coffee does have a mild, short-term effect on cortisol, but for most people, it is not harmful. Pay attention to your own stress and energy levels. If you are already feeling on edge in the morning, reconsider that cup of coffee. Otherwise, enjoy it without overthinking the exact timing.
Coffee and Cholesterol
Coffee contains a compound called cafestol, which has been shown to increase serum cholesterol levels. The concentration of cafestol varies dramatically depending on how the coffee is prepared:
High Levels: Cafestol is highly concentrated in unfiltered coffee, such as French press, Turkish, or Scandinavian boiled coffee.
Intermediate Levels: It is found in moderate amounts in espresso and coffee made in a Moka pot. *While espresso contains intermediate levels of cafestol, moderate consumption of espresso-based coffee may not have the same dramatic effect on serum cholesterol levels as boiled, unfiltered versions.
Negligible Levels: Cafestol is virtually absent in drip-filtered, instant, and percolator coffee because the paper filters trap the compound.
Research has shown that high consumption of unfiltered coffee (averaging 6 cups per day) can increase low-density lipoprotein (LDL) cholesterol by 17.8 mg/dL.
In summary, if you are concerned about cholesterol, filtered or instant coffee is the safest choice, as they contain negligible amounts of the cholesterol-raising compound cafestol
So… should you drink coffee?
For many people, coffee can absolutely be part of a healthy lifestyle and offer some meaningful health benefits. But more isn’t always better, and how you feel matters just as much as what the research says.
A few simple things to consider:
- How do you feel after you drink it?
- Do you need a lot of added sugar and sweeteners to enjoy your coffee?
- What’s your quality of sleep when you drink coffee in the afternoon?
- Are you relying on it to push through exhaustion?
- Does it support your routine or work against it?
