If you’re already on your third giant cup of coffee and it’s not even midday, you may want to consider whether it’s time to change this habit. That’s because while coffee is a readily available source of caffeine, it’s also a common culprit for unwanted side effects that go beyond the jitters.

Caffeine acts as a stimulant in the central nervous system, which leads to a boost in alertness and energy, research has shown.

Because of the size of its molecules, caffeine can easily pass through the membranes that line the digestive tract. This means that from your very first sip (or bite), the caffeine in your food or drink starts making its way to your bloodstream.

Caffeine energises the body by mimicking a compound called adenosine, which makes you feel awake, according to Sleep Doctor. This process strengthens the feel-good hormone dopamine and triggers the release of adrenaline, giving you a jolt of energy. A landmark study found that in healthy people, the average half-life (meaning how long something remains active in your body) is 5.7 hours from when it’s ingested. Because this is how long caffeine will remain active in your body, it’s also how long you can expect to feel its effects.

But have you ever noticed that some people can fall fast asleep immediately after downing a double shot of espresso, while others can’t have a single cup of coffee without feeling strung out?

Turns out, there are varying levels of sensitivity to caffeine.

According to the Mayo Clinic, most people can easily tolerate a daily dose of up to 400 milligrams (mg) of caffeine, which is the amount in about 20 ounces of coffee, without any negative side effects.

But about 10 percent of the population is considered hyposensitive to caffeine, according to Caffeine Informer, meaning that they can tolerate higher-than-normal amounts of caffeine without a problem.

And people with caffeine hypersensitivity cannot tolerate even the smallest amounts of caffeine without negative side effects.

What Is Caffeine Sensitivity, and What Are the Symptoms?

When someone has caffeine sensitivity, they feel the effects of caffeine much more strongly than those without a sensitivity. The person may feel as though they have had several shots of espresso after just a few sips of coffee.

“Insomnia when consuming caffeine, can also be an indication the caffeine has impacted your sleep cycle. If you experience a racing heartbeat or palpitations, consult your physician to determine what, if any, amount of caffeine is safe for you to consume,” says Erin Palinski-Wade, RD, CDE, a dietitian and author of the 2 Day Diabetes Diet.

Some additional symptoms of caffeine sensitivity or intolerance include:

  • Headache
  • Jitters
  • Insomnia
  • Restlessness
  • Anxiety
  • Racing heartbeat

If any of this sounds like you and you consume caffeine regularly, try tracking your intake and be sure to read food labels to spot hidden sources of caffeine. It’s also a good idea to voice your concerns to a doctor in case there may be another cause of your symptoms.

What Causes Caffeine Sensitivity?

There are a number of factors that can contribute to caffeine sensitivity, and unfortunately, you can’t control all of them. Here are some of the most common risk factors for caffeine sensitivity:

You’re a Man

Women naturally metabolise caffeine more quickly than men, research has suggested. Because caffeine takes longer for men to process, it stays in their system and can produce side effects for longer. As a result, simply being a man places you at an increased likelihood of being sensitive to caffeine.

… or a Woman on the Pill

If you’re a woman taking a birth control pill, the java playing field levels out somewhat. Caffeine competes for the same enzymes in the liver that also process oestrogen. When synthetic hormones are introduced in the body, as is the case with oral contraceptives, the body processes caffeine at about one-third the speed it would otherwise, according to one study.

Your Medication Is to Blame

Some types of medication may interact with caffeine, making its side effects more pronounced. For example, the Mayo Clinic points out that medications and supplements such as theophylline (Theo-24), which is used to treat respiratory issues, and echinacea, an herbal supplement, can both increase the effects of caffeine in the body. Check with your doctor or pharmacist to see whether any of your meds may be affecting how your body processes caffeine.

It’s in Your Genes

Believe it or not, there’s a genetic component to how the body processes caffeine, meaning that your genetic makeup alone can make you hypersensitive to caffeine. Research points to a variation in the ADORA2A gene, which correlates with variations in caffeine’s effect on sleep from one person to another. Another study, with 120,000 participants, identified six genes that may affect the way people metabolise and become hooked on caffeine.

You Don’t Usually Have Caffeine

Caffeine has a stronger effect on those who don’t consume it regularly compared with those who have built up a tolerance. Think of it this way: The more “practise” your body has at metabolising caffeine, the more efficient it seems to be at it. According to the Mayo Clinic, simply not consuming caffeine regularly can lead to a higher sensitivity to it.

You Have Baseline Anxiety

If you already have anxiety or high levels of stress, caffeine can worsen the symptoms you’re already experiencing. For example, one review from 2022 found that caffeine increased anxiety and risk of panic attacks in those with panic disorders, with about 51 percent of the 237 patients having a panic attack after consuming caffeine, compared to zero who had a placebo.

Energizing Drinks That Don’t Contain Caffeine

“If people are sensitive to caffeine I recommend they avoid caffeinated beverages completely,” says Lynn Grieger, RDN, CDE, a health, food, and fitness coach in private practice in Prescott, Arizona, and a medical reviewer for Everyday Health. If you’re looking to cut back on or completely eliminate caffeine in your life, it’s only natural to want to replace that habit with another. The undeniable comfort a warm beverage provides is hard to give up. Luckily, there’s no need to! Keep in mind that quitting caffeine cold turkey is not usually recommended because doing so can cause withdrawal side effects. “Reduce caffeine gradually to avoid fatigue and side effects such as headaches,” Palinski-Wade says.

“Aim to cut your caffeine intake by 25 percent every two to three days until you can keep it below 100 mg or less per day.”

Reducing Your Caffeine Intake? Try These Alternatives

Decaf Coffee and Decaf or Caffeine-Free Tea

“Coffee lovers may find that using decaffeinated coffee works well for them, but some of my coffee-loving clients tell me that they have greater success reducing caffeine when they replace coffee with a naturally caffeine-free herbal tea such as chamomile tea,” says Grieger. Some teas are naturally caffeine-free, while others have the caffeine removed – both are great choices. Keep in mind that even decaf coffee and decaf tea do contain a small amount of caffeine, so they may not be the perfect choice for those looking to go completely caffeine-free.


With its natural carbonation and a significantly lower amount of caffeine than tea, kombucha can make a healthy and energy-boosting choice. It’s also a great lower-sugar alternative to soda drinks.


Wheatgrass is a source of essential vitamins and minerals and, while not the tastiest choice, a shot of it may help to give you a little extra burst of energy without any caffeine.

Mushroom Coffee Alternative

If you’re looking for a warm beverage that mimics the earthy flavour of coffee without the caffeine, try mushroom blends.

Chicory Herbal Coffee Substitute

Made from natural ingredients such as chicory and herbs (there’s even a variety that contains dandelion), and it may be the perfect warm and flavoursome replacement for your daily coffee.

Golden Milk Latte Mix

With turmeric, dates, cardamom, and vanilla as its main ingredients, a golden milk latte can be easily made and provide you with the warmth you crave along with a good dose of calcium from the milk. It can also be made with your favourite non-dairy milk to make it completely dairy and caffeine-free.

Other Proven Strategies to Help Boost Your Energy Naturally

Foods and beverages aren’t the only source of improved energy levels. There are a host of lifestyle habits you can adopt that may help with energy and, of course, are caffeine-free.

Get Moving!

While it may seem counterintuitive to expend energy to gain more, the truth is that exercise has been shown to do just that. According to Harvard Health Publishing, exercise increases energy supply through promoting better sleep, oxygen circulation, and mitochondria reproduction in the cells. The recommended amount of exercise for adults is at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity activity per week, according to the Physical Activity Guidelines for Americans.

Get Enough Sleep

If there’s one thing that can send you running to a cafe, it’s not getting enough sleep. For optimal health, the Sleep Foundation recommends adults get seven to nine hours of sleep each night.

Practise Yoga and Mindful Meditation

Slowing down and breathing deeply won’t only make you feel calmer – this approach can also increase energy. According to research, both yoga and mindfulness meditation can improve mood, focus, and energy levels.

Cut Back on Screen Time

Living with your phone in your hand can drain your energy. According to one study, use of light-emitting screens before bed (think cell phones, tablets, e-readers, and television) increased the time it took to fall asleep, decreased the quality of sleep, and decreased the feeling of alertness the following morning. Before bed, skip the Netflix binge or Instagram scrolling in lieu of reading a book or doing some deep-breathing exercises for a better night’s sleep.

Be a Superhero

As it turns out, Superman was on to something! Standing in a high-power stance such as with your head held high, feet apart, and hands on your hips, much like Superman, for just one minute can naturally increase energy levels according to research.

Get Some Sunshine

Vitamin D is known as the “sunshine vitamin” for a reason. When the sun’s rays hit our skin, it tells our bodies to make more vitamin D. And this process can do wonders for our energy and mood. Vitamin D deficiency has been linked to muscle fatigue notes research. In addition, vitamin D levels in the body can have a direct effect on depression and other mood disorders, as described in one paper.

To get your fix, the National Institutes of Health’s Office of Dietary Supplements (ODS) recommends standing in the sun for 5 to 30 minutes a couple of days per week. Direct sunlight is key – your body won’t synthesise vitamin D if you’re being exposed through a screen or window, for instance. And know that living in certain latitudes and having darker skin may also affect how much vitamin D you’ll make.

Have a Healthy Breakfast

Breakfast is the most important meal of the day! A protein-rich breakfast that also contains whole grains is a perfect balance of energy-boosting nutrition. For example, eggs with whole-grain toast, yogurt with whole-grain cereal, or steel-cut oatmeal with nuts would all be nutritionally balanced and filling choices. Whole-grain carbohydrates and protein both slow digestion, leading to more consistently high energy hours after the meal, as noted by Harvard Health Publishing.

Drink More Water

Research has found that even mild dehydration by just 1.5 percent of the body’s normal fluid amount can significantly affect energy, mood, and brainpower because it decreases the volume of blood in the body and, therefore, the amount of blood reaching the brain. “I encourage all of my clients to make plain, unflavoured water their primary beverage,” says Grieger.

Get Enough Vitamin B12

Most Americans get plenty of vitamin B12 to meet their needs because it is found in high amounts in foods such as dairy products, fortified breakfast cereals, trout, salmon, tuna, clams, and beef. But vegetarians and vegans, those with digestive issues, and those over age 50 are more likely to become deficient in vitamin B12. Under normal circumstances, vitamin B12 helps your body break down food into glucose, which the brain uses for energy. As a result, vitamin B12 deficiency can zap energy levels, according to the ODS, and so getting it from a supplement can increase energy and endurance.

If you think you’re sensitive to caffeine, now is a great time to move toward a less caffeine-dependent life. Determine which foods, beverages, and lifestyle habits are the best fit to help you increase your energy levels naturally, and start cutting back on caffeine today. With a few simple changes, you’ll have so much energy that you won’t even miss that morning cup of coffee.