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Ranking the best caffeine pills of 2021

Written by John Davis

Last updated: December 8, 2020

Caffeine is one of the most reliable and effective ways to perform better and stay alert during the day or into the night.

Caffeine pills are great if you need a precise dose of caffeine for mental acuity or physical strength and endurance.

Intimidated by the number of options? Our research team went through all of the best caffeine pills on the market, ranking them in order of their quality.


1. Performance Lab Stim

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Performance Lab Stim is our #1 caffeine pill recommendation this year.

It contains the ‘smart caffeine’ combo of L-Theanine and natural caffeine at the correct 2:1 ratio which has been shown to work in clinical studies. It boosts mental focus, physical endurance, and strength levels without jittery side effects.

Not only that, Performance Lab Stim is loaded with L-Tyrosine to further improve your concentration. All of this while offering B Vitamins to restore the nutrients that caffeine depletes – pretty smart, huh?

As a bonus to vegans and vegetarians, Performance Lab Stim’s capsules are made from prebiotic fiber (instead of the cheaper cellulose or gelatin options that other companies use). This means that it supports healthy digestion while being completely vegan-friendly.

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2. Zhou Energy + Focus

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Zhou Energy + Focus is our top choice because it combines a high 200 mg dose of caffeine with the mediating and synergistic effects of L-theanine.

One reason why green tea is particularly effective at boosting mental and physical acuity without side effects is because of the interaction between caffeine and L-theanine, which work together for more optimal effects than caffeine alone.

The L-theanine helps prevent some of the negative effects that caffeine can cause, and Zhou takes full advantage of this. It’s also got a vegan-friendly cellulose capsule, and the only ingredient other than caffeine and L-theanine is rice flour. You really can’t go wrong with this one.

3. Nutricost Caffeine

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Nutricost offers one of the simplest caffeine supplements out there, with 200 mg of caffeine per capsule and only two other ingredients: gelatin and rice flour.

It’s hyper-minimal; the only bad news is that vegetarians and vegans might want something other than gelatin (an animal product) to make up the capsule.

4. BulkSupplements Caffeine

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It doesn’t get any simpler than this. BulkSupplements delivers a 200 mg caffeine supplement in a gelatin capsule, with zero additional ingredients.

Yes, vegetarians and vegans will be put off by the cow-derived gelatin, but everybody else can make this their number one choice for a straightforward high-dose caffeine supplement.

5. Genius Caffeine

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The innovative spin that Genius puts into its caffeine supplement is its trademarked slow-release caffeine formulation.

While most forms of caffeine are absorbed very rapidly, Genius Caffeine claims that their micro-encapsulated form of caffeine will deliver a steady stream of the supplement to your blood over a longer period of time, providing a smoother ramp-up and ramp-down of the effects.

This should help fend off some of the adverse effects of caffeine for those who are sensitive to them, too.

6. Natrol High Caffeine 

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Natrol provides an extra strength serving of caffeine (200 mg) designed to complement and augment the focusing and attention-boosting properties of caffeine.

If the simple rush of caffeine isn’t cutting it for you, think about going for Natrol high caffeine-especially if you have cognitively demanding tasks ahead of you.

7. SmarterVitamins Caffeine + L-Theanine

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SmarterVitamins shows that they really know their stuff with regards to the dynamics of caffeine inside the body with this supplement.

Providing L-theanine alongside caffeine is clever, because research has found that several of the benefits of green tea can be traced to the synergistic action between caffeine and the amino acid L-theanine. With 200 mg of caffeine per softgel, it’s not lacking in the energy department, either.

8. ProLab Caffeine Maximum Potency

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If all you want is a simple caffeine supplement that delivers a high dose quickly, ProLabs is a very solid choice. With 200 mg of caffeine per capsule and no time release agents, you’ll get a quick rush of caffeine to give you an extra boost of energy.

There are a few more binders and excipients than strictly necessary, but that’s hardly a reason to discount this supplement.

9. Jet Alert Caffeine

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Jet Alert is a good choice if you know you need a smaller and more calibrated dose of caffeine. At 100 mg per capsule, it’s a little easier to dial in the exact dosage you need.

Since a lot of the science on caffeine delivers caffeine at doses proportional to the body mass of the participants, you’ll want something a little more precise to dial in your dose. This is where a smaller dose supplement like Jet Alert comes in handy.

10. Vali Time Release Caffeine

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Vali provides a time release caffeine supplement, but with only 100 mg of caffeine per pill.

If you are very small, or are sensitive to higher doses even in time release formulations, this might be a good choice, but otherwise, there are better time release formulations on the market.

Category winners

Best caffeine pill overall: Performance Lab Stim

Performance Lab Stim is a unique combination of caffeine, theanine, B-vitamins, and tyrosine. These ingredients work together to maximize your energy levels and minimize unpleasant side effects, making for the best all-around caffeine pill on the market. 

Best caffeine pill for sports performance: Genius Caffeine

Genius Caffeine is perfectly suited for sports performance thanks to its micronized formulation—a special formulation of caffeine that’s released over a long period of time to sustain long, hard workouts and efforts more effectively than standard caffeine pills. 

Best caffeine pill for women: Performance Lab Stim

Women are sometimes more susceptible to the adverse effects of high doses of caffeine. Performance Lab Stim, with a moderate dose of caffeine and several complementary ingredients to mediate the negative effects of caffeine, is a great way for women to capitalize on the benefits of caffeine while minimizing the side effects.  

Best caffeine pill for weight loss: Genius Caffeine

Genius Caffeine’s extended release formulation makes it great for weight loss, as it can sustain a high rate of fat oxidation throughout the day, especially if you take it in the morning. 

Best caffeine pill for studying: Zhou Energy + Focus

Zhou Energy + Focus supplies a solid 100 mg dose of caffeine alongside L-theanine to calm your nerves and blunt any negative effects from caffeine. If plain caffeine gives you jitters and anxiety when you try to study, Zhou Energy + Focus is the perfect solution. 

Best caffeine pill for headaches: Nutricost Caffeine

Yes, caffeine boosts your cognitive power, but it can also banish headaches when taken at the right dose (research suggests at least 130 mg). We recommend Nutricost Caffeine, which has 200 mg per capsule—perfect for dealing with headaches and migraines.

Who should buy caffeine pills?

Caffeine pills are great for anyone who wants to take advantage of the myriad benefits of caffeine without having to bother with coffee, tea, or energy drinks.

Caffeine has incredible benefits for cognitive function, athletic performance, and weight loss—caffeine is simultaneously a nootropic, performance enhancer, and a weight loss supplement.

So, if you need to power through a project at work, perform well in an athletic event, or increase your energy expenditure during a diet, a caffeine pill is a fast and easy way to do it. It’s also popular for sustaining weight lost after successfully completing a weight loss program.

You don’t need to bother with brewing coffee, steeping tea, or dealing with the other ingredients you might find in a pre-workout supplement.

How we ranked

To formulate our caffeine pill rankings, we made a list of all the currently-available products that delivered an adequate dose of caffeine for cognitive and physical performance.

That meant calculating minimum effective doses for people with a range of body masses—caffeine pills that delivered less than 100 mg of caffeine were eliminated, as anything less than this would not be effective even for someone who only weighs about 100 pounds.

Minimum effective doses of caffeine start to show up at about one to three mg of caffeine per kg of body mass, so a 50 kg person (~110 pounds) would need at least 100 mg of caffeine to start seeing significant physical and cognitive performance benefits.

Larger people, of course, will need a higher dose, which is why most of our caffeine pills that ended up higher in the rankings had more like 150 or 200 mg per capsule or tablet.

Caffeine is great, but one advantage that coffee and tea have on pure caffeine is the presence of other compounds, like theanine and chlorogenic acid, that help modulate the effects of caffeine on your central nervous system.

Some people are fine with plain caffeine, but others can get better performance and fewer side effects with a caffeine pill that provides caffeine alongside some hand-picked extras. Theanine was one we were particularly interested in, because it helps ameliorate the jitters and anxiety that can come along with higher doses of caffeine.

We required caffeine pills without extras like theanine to be exceptionally pure, and dropped any caffeine pills that had too many binders, fillers, and additives.

For products with additional ingredients like theanine, we looked for sufficient doses of these additional biologically active ingredients, and made sure there weren’t so many extras that the supplement got bloated with active ingredients.

Our final rankings are a mix of moderate and high-dose caffeine pills, some of which provide just pure caffeine, while others provide caffeine supported by an appropriate amount of theanine or other mediators. These are the best caffeine pills on the market.


Caffeine is one of the oldest and most versatile supplements in use. Taking caffeine pills can be helpful whether your goal is to run faster, lift more weight, study harder, or be more vigilant.

Caffeine’s effects across a wide variety of tasks are well-characterized, so it’s very easy to figure out how much caffeine you’ll need and when to take it in order to meet your performance goals.

The benefits of caffeine pills stretch from resistance training to weight loss to endurance training to mental performance. There is a wide range of research testifying to the efficacy as a supplement to increase your performance in all of these fields.

For resistance training, as well as other high intensity, short duration exercise, caffeine appears to blunt feelings of fatigue, increasing your ability to lift more weight for more reps, which is why caffeine is a popular ingredient in pre-workout shakes.

One study, published in 2007 in the International Journal of Sports Physiology and Performance studied the effects of a dose of caffeine on bench press and leg press in a group of volunteers (1).

The effects of the dose of caffeine on maximum number of reps, as well as perceived feelings of fatigue, were compared to a placebo given to a control group. The researchers found that bench press maximum reps (at a constant weight) increased from an average of 10 in the control group to an average of 12.5 in the group given caffeine.

The subjects given caffeine reported feeling the same level of fatigue as the subjects given the placebo, indicating that the caffeine increases your performance across the board. In other words, applying the same effort results in better performance after you’ve taken caffeine.

Similar results have been found in studies on endurance exercise performance. A systematic review published in 2009 in the Journal of Strength and Conditioning Research looked at 21 different studies of caffeine’s effect on endurance performance (2).

After reviewing the data and pooling results, the researchers concluded that caffeine can improve endurance performance by three percent or more.

That may not sound like much, but it would amount to finishing a marathon about a mile ahead of where you’d be without caffeine. Moreover, these findings were robust and supported by many studies.

Caffeine is also well-suited for boosting the performance of short-term anaerobic exercise, as long as it involves a short, sustained, high-intensity effort lasting at least 60 seconds.

That was the conclusion of a 2009 publication in the journal Sports Medicine by researchers at Texas A&M University and the University of North Alabama (3).

In contrast, caffeine is not as well-suited for very high intensity sessions with short rest between repetitions, like a HIIT training session.

The benefits of caffeine extend to mental tasks, too. A scientific article by R. H. S. Ruxton found that moderate caffeine consumption improves reaction time, boosts mood, and increases alertness (4).

Perhaps most importantly for mental performance, it also increases your short term memory recall: this means you can keep more pieces of information in your head at once, making your studying, planning, and work on cognitively demanding tasks much more effective.

If you are focused on the mental benefits of caffeine, one thing you can try is taking a caffeine pill that includes L-theanine as well as caffeine.

There is a large body of evidence that these two compounds work together to boost your mood and mental function beyond what caffeine normally can do. Initial evidence for this effect came from studies of the mood and mental acuity boosting powers of green tea extract; researchers noted that L-theanine appeared to account for some of the effects independent of caffeine (5).

Direct studies of the combined effect of L-theanine and caffeine started to explore the effects of both together. A paper published in 2008 in the journal Psychopharmacology examined just this combination (6). The researchers found that, while caffeine alone has a tendency to cause jitteriness, when combined with theanine, this tendency disappears.

This is good news for people who are sensitive to the negative effects of caffeine, because it suggests they can be blunted or prevented by a caffeine pill which also includes theanine.

Caffeine is a very effective way to increase caloric expenditure. One consistent finding from epidemiology research is that people who drink coffee and tea are less likely to be overweight.

This association remains, even after controlling for other factors like dietary patterns. While additional phytonutrients definitely play a role in this relationship (hence green tea extract and green coffee bean supplements), there’s no denying the role of caffeine in these relationships.

Research published as early as 1990 demonstrated that caffeine exerts a significant thermogenic effect: a study in the Journal of Clinical Nutrition used healthy volunteers who took increasing doses of caffeine, and was able to show that the thermogenic effects of caffeine increase linearly as a function of the dosage (7).

Moreover, the researchers found that caffeine alters specific biochemical pathways, leading to changes in cellular metabolism. Other work published in the American Journal of Clinical Nutrition showed that this thermogenic effect works in lean people as well as formerly obese people who have finished a weight loss program (8).

These findings explain why caffeine is a common ingredient in weight loss pills, so if you are looking for a simple way to ensure you have a high overall daily energy expenditure and don’t want to bother with the mixture of caffeine and herbal ingredients that you’ll likely get in a weight loss pill, a caffeine pill is an effective way to get the same benefits.

Side effects

Given that it is so potent, it should not be surprising that caffeine has some side effect when taken in excess. According to the Mayo Clinic, taking too much caffeine (defined as over about 400 mg per day) can lead to headaches, nausea, insomnia, restlessness, tremors, and a rapid heartbeat (9).

Extremely high doses have even been associated with fatal overdoses. When taking caffeine pills, it’s important to know where the other sources of caffeine in your diet are.

If you already are taking a weight loss supplement, for example, you might be getting a substantial dose of caffeine as it is. Caffeine’s effects take several hours to wear off, so spread out the caffeine you do consume throughout the day.

Recommended dosage

Caffeine is most effective when its dosage is calibrated to your body weight. Most scientific studies recommend doses of three to six milligrams of caffeine per kilogram of body mass.

This means that if you weigh 80 kg (175 pounds), you will see optimal results at doses of caffeine between 240 to 480 mg of caffeine. Sometimes it’s hard to get exactly the correct dosage, given that caffeine pills usually come in multiples of 100 mg, but the dosage of caffeine is fairly forgiving.

Some research suggests that doses that are pretty low (below 3 mg per kg) are still effective (10). As far as timing, you’ll want time your caffeine intake so that you take a caffeine pill about 60 to 90 minutes before when you want to be at peak performance.

The effects last for several hours, so you don’t need this timing to be perfect. A time release formulation will help deliver a longer, steady stream of caffeine to keep you operating on a high level for a long time, but this might happen to the detriment of absolute peak performance. 

This is a worthy trade, though, if you need to be working at high intensity (mentally or physically) for several hours at a time.


Q: Are caffeine pills bad?

A: Caffeine pills get a bad rap because it’s quite easy to overdo it: the relatively long delay (60-90 minutes) between taking a pill and experiencing its full effect, and the high dosage per pill that’s common in many over the counter caffeine pills, makes it easy to blow past the optimal dose and get jitters and anxiety.

Caffeine does have some serious negative side effects if you take it in extremely large doses, but when taken at moderate doses it’s both well-tolerated and remarkably effective.

Many of the physical, cognitive, and fat-burning effects that people strive to get through complicated combinations of herbal compounds could be much more easily garnered with a 150 or 200 mg dose of caffeine.

So, caffeine pills are only bad if you don’t use them intelligently. At the right dose, caffeine is a very effective and versatile supplement.

Q: How long does a caffeine pill last?

A: You can expect the greatest effects of caffeine to last for a few hours. It takes an hour or so for a caffeine pill to achieve maximum effect, and by five or six hours, the effective dosage has dropped in half (this time duration is called the elimination half life).

One important thing to note about the effects of caffeine, and its elimination half life, is that it can be much longer (sometimes doubling the half life to ten or twelve hours) in women who are taking birth control pills, due to an obscure interaction.

This doesn’t have any real consequences in terms of caffeine’s efficacy; it just means that caffeine will last a lot longer in your system in this case, so you’ll have to be more thoughtful about when, if at all, to take another caffeine pill.

Q: What do caffeine pills do to your body?

A: Caffeine is a potent stimulant that modulates your body’s central nervous system, which accounts for its broad-reaching physical and mental effects.

Boosting athletic performance and cognitive performance at the same time is very hard to do unless you act on the central nervous system, which is exactly what caffeine pills do.

Additionally, caffeine also ramps up your body’s cellular metabolism, which boosts your baseline energy expenditure (and accounts for the thermogenic, weight-loss friendly effects of caffeine pills).

Q: Do caffeine pills help you lose weight?

A: Caffeine is a well-known thermogenic compound, so yes, caffeine can help you lose weight by increasing your body’s baseline caloric expenditure.

The effect is dose-dependent, with higher doses of caffeine burning more calories, but you do need to balance this with the negative side effects of caffeine at higher dosages.

Caffeine pills, or calorie-free caffeinated drinks like coffee and tea, are particularly effective ways to achieve the thermogenic effect of caffeine because you incur no additional energy intake (versus, say, a soda or energy drink, where the calories due to the sugar might offset any benefit in thermogenesis).

Q: Are caffeine pills good for studying?

A: Yes, one of caffeine’s most well-researched aspects is its nootropic potential: caffeine boosts cognitive performance, attention, and memory, particularly when you are sleep deprived.

The effect is so strong that the military has awarded specific contracts for companies to develop caffeinated products for military ration kits, so caffeine is a good tool to improve your studying, especially late at night.

Of course, you do need to be mindful of the fact that you won’t sleep well after taking a caffeine pill to stay up late, and sleep is very important for solidifying what you’ve learned during a study session.

So, caffeine is great for cognitive performance right now, but you do need to ease off the caffeine and sleep if you want to retain and recall information later.

Q: Should you take caffeine pills or drink coffee?

A: Caffeine pills are great if you need a fast, transportable, and easy way to boost your body’s caffeine levels. Coffee can deliver caffeine too, but it takes slightly longer to kick in.

Plus, the caffeine content of coffee varies from roast to roast. However, coffee contains compounds like chlorogenic acid that modulate the effects of caffeine in your body, and coffee is rich in many antioxidants that you will not get in a caffeine pill.

If you want short-term performance benefits (physical or mental), caffeine pills have the edge compared to coffee. However, if your goal is long term health, you should opt for coffee instead.

Q: How long does it take for caffeine pills to kick in?

A: Caffeine levels in the blood reach a peak about 60 to 90 minutes after ingesting a caffeine pill. The rise in blood caffeine levels will be slower if you take caffeine pills with a large meal, but aside from this, caffeine pills are quite reliable in their timing, which is one of their prime advantages—you know exactly what you will get.

Q: How many caffeine pills can you take?

A: Caffeine’s side effects ramp up at higher dosages, and fortunately, you don’t need a crazy high dose of caffeine to get optimal thermogenic and performance benefits.

Typically about three mg of caffeine per kilogram of body weight is the sweet spot for optimal benefits and minimal side effects; this translates into about 200 to 300 mg for most people.

Serious side effects don’t appear until much higher doses (some scientific studies have used up to nine mg per kg of body mass) but there is really no need to strive for an excessive dose.

Q: How are caffeine pills made?

A: Caffeine pills are usually made by purifying the caffeine that’s extracted from decaf coffee during the decaffeination process.

A solvent, usually water or supercritical carbon dioxide, is used to pull the caffeine out of the coffee beans. The beans then become decaf coffee, and of course the caffeine is left over and can be purified and packaged into caffeine pills.

It’s also possible to synthesize caffeine, but given the amount of decaf coffee that’s made every year, coffee beans are a more common source.

The pure caffeine powder is then pressed into tablets or pushed into capsules, along with binders and stabilizers (hopefully not too many).

Q: When should you take caffeine pills?

A: The optimal timing for taking a caffeine pill is about an hour or so before you need to perform at your best. You should also keep in mind the “come-down” from caffeine; given that caffeine (obviously) inhibits your ability to sleep, you should also time your caffeine pill dose so that it doesn’t keep you up super late, unless that’s what you want.

You’ll get maximum performance benefits from caffeine for a few hours, so you have some flexibility with when you take caffeine pills.

For weight loss, in contrast, you want to maintain a moderate level of caffeine throughout the day, so it’s best to take a caffeine pill early in the day, then let the long elimination half life of caffeine sustain your body’s caffeine levels throughout the day.

Even ten to twelve hours after taking 200 mg of caffeine, you’ll still have an effective dose of 50 mg in your body.

Related articles


For strong, evidence-based performance enhancement, caffeine is the golden standard. There can be no dispute that caffeine pills are a highly effective supplement when it comes to improving your performance in resistance training, endurance events, and a wide range of mental tasks.

It takes a little work to figure out the right dosage for you that will lead to the optimal performance level with the lowest potential for side effects, but there’s no doubting that it’s worth it.

If you find yourself vulnerable to the negative effects of caffeine, or if you are particularly focusing on the mental acuity-boosting properties of caffeine, try a caffeine pill that includes L-theanine as well, since these two compounds work together synergistically to improve mental performance and reduce side effects like jitteriness.

For BodyNutrition‘s #1 caffeine pill recommendation, click here.


John Davis

John Davis is a Minneapolis-based health and fitness writer with over 7 years of experience researching the science of high performance athletics, long-term health, nutrition, and wellness. As a trained scientist, he digs deep into the medical, nutritional, and epidemiological literature to uncover the keys to healthy living through better nutrition.