How Long Do Caffeine Pills Last? (Time Taken to Wear Off)

Benedict Ang, CPT, PN1-NC
Published by Benedict Ang, CPT, PN1-NC | Staff Writer & Senior Coach
Last updated: June 20, 2024
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It's a startling realization that our daily energizer, caffeine, is in the same psychostimulant class as potent drugs like cocaine and methamphetamine.

Given this, it's not surprising that overindulgence can lead to significant health risks, even fatal consequences.

The risks are particularly high with concentrated forms of caffeine, such as caffeine pills.

So, if you choose to use them, it's crucial to know how long these pills stay in your system, the factors affecting their duration, and the potential health implications.

Quick Summary

  • Caffeine pills remain active in the bloodstream for 4–8 hours, with their effects influenced by dosage, genetics, and individual tolerance.
  • The longevity of caffeine in the system is determined by the amount consumed, genetic factors, individual tolerance, and the state of hydration and fullness.
  • Most health professionals, including the FDA, recommend a daily caffeine limit of 400 mg for adults, equivalent to about four or five cups of coffee, to prevent adverse effects.
  • From my own caffeine adventures, I've found that while pills are a nifty shortcut to alertness, it's crucial to respect their potency and know your boundaries for a safe experience.

How Many Hours Do Caffeine Pills Stay Active?

Caffeine pills typically stay active in the body for a duration ranging from 4 to 10 hours, with the specific duration influenced by individual factors such as body composition and metabolism, as stated by the Cleveland Clinic. This means that if you consume 200 mg of caffeine at 8 a.m., half of it will still be circulating in your bloodstream by 2-3 p.m. [1].

In contrast, caffeine pills begin to take effect within 45 minutes after ingestion and reach their peak effects approximately an hour later, as reported in a 1997 article from the Pharmacology, Biochemistry, and Behavior journal [2].

Due to the high bioavailability of caffeine, it's rapidly absorbed, ensuring that almost the entire consumed amount is utilized by the body.

4 Factors That Influence Caffeine Half-Life

I've always been curious about why caffeine affects some of my friends differently. As it turns out, how long it stays in our system varies from person to person, and here are some reasons why.

1 - The Amount You Take

caffeine pills amount

The doses of caffeine you’re used to consuming influence the time needed for your body to process and eliminate it. The higher the caffeine dosage, the longer its half-life.

Remember that many over-the-counter dietary supplements (like weight loss pills or pain killers), packaged foods (including chocolate and other desserts), and beverages (e.g., tea, soda, beer, energy drinks, and even decaf coffee) contain added caffeine [3,4].

One study published in the American Journal of Clinical Pathology showed that caffeine might circulate in the bloodstream of people with compromised liver function significantly longer than usual (even for 168 hours) [5].

“For reference, a 12-ounce can of a caffeinated soft drink typically contains 30-40 milligrams of caffeine, an 8-ounce cup of green or black tea 30-50 milligrams, and an 8-ounce cup of coffee closer to 80-100 milligrams. Caffeine in energy drinks can range from 40-250 mg per 8 fluid ounces.”


So, to stay on the safe side, you need to be aware of all the caffeine sources, so always ensure you check the product labels and follow the dosage instructions when taking caffeine pills.

2 - Your Genes


Per a 2014 study published in Molecular Psychiatry, genetic factors also influence how long caffeine stays active in your bloodstream, your consumption habits, and the effects of caffeine on your body [6].

According to studies, a gene called CYP1A2 is up to 95% responsible for caffeine metabolism, whereas a gene called AHR regulates how CYP1A2 is expressed in the liver [7].

People who have any defects or lack of this gene metabolize caffeine longer than others and may be more sensitive or even allergic to this potent central nervous system (CNS) stimulant.

A 2016 study from Nature has also found that a variation of the gene PDSS2 regulates the speed of metabolizing caffeine and the amount you need to feel its effects [8].

3 - Your Tolerance and Sensitivity

Caffeine tolerance determines how individuals react to stimulant intake in different doses.

It differs from sensitivity to caffeine, which refers to the ability of your body to metabolize this stimulant depending on your unique genetic predisposition.

As explained in a 2010 study published in Pharmacology, minor changes in the CYP1A2 gene influence how efficiently an individual can process caffeine and eliminate it from the body [9].

Also, the AHR gene regulating the CYP1A2 gene function, as well as the type of adenosine receptors in someone’s brain, influence a person’s sensitivity to caffeine.

In general, caffeine counters tiredness by blocking the effects of adenosine, a chemical that accumulates in our body and promotes sleep.

So, if you lack adequate adenosine receptors, the caffeine molecules can’t bind to them, so you’ll probably be less responsive to its stimulating effects.

4 - How Hydrated and Full You Are

water on glass

Many people claim that coffee consumption on an empty stomach leads to faster caffeine absorption than drinking coffee with or after a meal.

Similarly, consuming caffeine in pills after a heavy meal may take longer to kick in, and the effects may also be weaker than from caffeinated pills taken on an empty stomach.

Also, a study from 1988 confirmed slower caffeine absorption in individuals with a full stomach who were given meals that were hard to digest [10].

There are some notable differences between coffee and caffeine pills though.

However, some consumers experience digestive issues when using caffeine pills on an empty stomach.

That’s because your body produces hydrochloric acid during caffeine ingestion, which can irritate your stomach.

Coffee acts as a diuretic, stimulating urine excretion and flushing the sodium from your body along with the water. This may lead to dehydration and mineral deficiency.

Drinking water helps minimize these unwanted effects.

Related Articles:

What Is Considered Safe Caffeine Consumption?

caffeine consumption

Generally, experts like the FDA and Mayo Clinic say that safe caffeine consumption means sticking to a daily limit of around 400 mg to avoid potential health issues and caffeine-related symptoms, although safe caffeine consumption varies from person to person [11,12].

This amount hasn’t typically been associated with harmful side effects, which include:

  • High blood pressure
  • Irregular heart rate
  • Fast heartbeat
  • Sleep problems/insomnia
  • Indigestion
  • Light-headedness
  • Muscle tremors and convulsions
  • Jitters
  • Anxiety
  • Mild to severe headaches or migraines
  • And other caffeine overdose symptoms, even cardiac arrest and death

According to the American Academy of Pediatrics, children and adolescents shouldn't consume caffeine at all due to potential vulnerabilities to sleep loss and other harmful effects [13].


Is Caffeine Pill Better Than Coffee?

Whether caffeine pills are better than coffee depends on individual preferences and needs. Caffeine pills offer a precise dose of caffeine without additional calories or substances found in coffee. However, coffee provides other beneficial compounds like antioxidants and may have its own unique health benefits.

Do Caffeine Pills Burn Calories?

Yes, caffeine pills can burn calories due to caffeine's thermogenic effect, which slightly raises metabolism. However, this effect is generally modest and should not be solely relied upon for significant weight loss.

Can You Take 2 Caffeine Pills at Once?

Taking two caffeine pills at once is generally not recommended. The safe dosage of caffeine varies depending on individual tolerance, but it's typically advised to stay below 400 milligrams per day. Many caffeine pills contain about 200 milligrams per pill, so taking two at once could lead to excessive caffeine intake.


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About The Author

Benedict Ang, CPT, PN1-NC
Staff Writer & Senior Coach
Benedict Ang, CPT, PN1-NC is an ex-National Soccer player turned MMA and Kickboxing champion, with ACE CPT and PN1-NC certifications. His advice is rooted in education and experience, ensuring that readers receive scientific and battle-tested insights. His mission is to empower his clients and readers to realize their potential and become the best versions of themselves.
Learn more about our editorial policy
Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
Learn more about our editorial policy

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