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Caffeine Benefits, Side Effects & Safety Information

Published: 13th May 2018. Last updated: 21th July 2019.

Luna Smithton

Editor & Fact Checker


Caffeine is a psychoactive crystalline compound found in over 60 plants, particularly in tea and coffee. It is a natural central nervous system stimulant of the methylxanthine class. It works by speeding up the messages between the brain and the body and can therefore increase alertness and prevent the onset of tiredness. It can be synthesized in laboratories and is often added to products such as energy drinks and supplements as well as being used in weight loss products.

The Potential Benefits of Caffeine

Below we've listed every potential benefit we've found with credible scientific backing:

It May Help With Memory

Studies on memory retention have found that consuming caffeine can help with short term memory. Individuals with moderate to high caffeine intake (average 710mg/week) were found to perform better in memory tests than participants with low caffeine intake (average 178mg/week).

Researchers also found that the higher the caffeine intake, the better the participants performed.

The most pronounced effects of caffeine seem to be on middle-aged people (those aged 26-54). [1][2]

It May Help Stimulate Hair Growth

Caffeine has been found to stimulate hair growth when rubbed as a solution into the scalps of balding men.

One study found that fourteen men whose follicles were placed in solutions of caffeine had greater hair growth than those who did not (even when those follicles were also exposed to DHT, the hormone responsible for hair loss).

People wishing to use caffeine for hair loss should not consume it due to the concentration needed (drinking it would stop your heart); use a caffeine shampoo instead or opt for a DHT blocker. [3][4]

It May Help With Weight Management

Caffeine is a popular ingredient in weight loss products such as protein shakes and meal replacement drinks as well as health supplements.

Certain studies have found that, when taken in large enough quantities, caffeine can help to increase metabolic rates for a short period, leading to the increased burning of calories. Caffeine also releases the hormone Epinephrine that tells the body to break down fatty acids from tissue and release them into the bloodstream to be used as energy.

As caffeine also makes people feel more awake, consumers are less likely to reach for weight-gaining sugar during energy slumps. [5]

It May Be Useful For Reducing The Risk of Heart Disease

Researchers at Stanford University found that caffeine can be responsible for blocking the gene that causes chronic inflammation that is common during the aging process. This inflammation can eventually lead to high blood pressure, heart disease and hardening of the arteries. University researchers found that caffeine helped to reduce age-associated inflammation in people who consumed the drug regularly. [6]

How To Supplement Caffeine Safely

The methods of using caffeine vary from social and cosmetic to medical settings.

The most common methods of using caffeine are:

  • As a drink (for example in Coca Cola and other popular energy drinks)
  • As pills (as a supplement)
  • As a cream (in cosmetic face and anti-cellulite creams)
  • As an ingredient in food

The optimal dosage amount for caffeine is generally agreed to be no more than 300-400mg of caffeine consumed daily in several smaller doses (with a single dose being no more than 200mg); consumers should also drink plenty of water to counteract the dehydrating effect of the drug. In cosmetic creams the appropriate dosage should be on the packaging.

Caffeine Side Effects List

There are always risks to taking any kind of drug even if they have been used safely by others, so talk to your doctor before changing your diet to include more caffeine than you are used to.

The following side effects could potentially be:

  • Insomnia (inability to sleep)
  • Nervousness
  • Restlessness
  • Decreased appetite
  • Nausea and vomiting
  • Increased heart rate and respiration
  • Headaches (especially when ‘withdrawing’ from caffeine consumption)

Note: Your body will adapt to the amount of caffeine it is used to consuming; if you start drinking caffeine after having none for a while you are more likely to experience these effects. Stopping caffeine consumption can lead to headaches and a dry mouth among other symptoms; contact your doctor if you are worried.

Overall, Is Caffeine Safe?

When used responsibly caffeine is very safe, when abused it can be deadly.

Caffeine is consumed by many people on a daily basis in the form of tea, coffee and chocolate. Up to 400 mg per day is generally considered safe (200mg or less for pregnant women), although some people may be particularly sensitive to its effects.

In large amounts it is unsafe and deaths have been recorded from overdoses, which is why it's actually illegal for US companies to sell bulk caffeine powder direct to consumers! [7]

Despite it being largely safe, you should not consume caffeine if:

  • If you’re a child under the age of 18: Children under 18 should not consume caffeine as studies have not been carried out on the long-term effects of childhood caffeine consumption.
  • If you are pregnant: Ideally pregnant women should eliminate caffeine from their diets as the drug crosses the placental barrier to the baby and there has not been sufficient study into the effects on the unborn child.

Caffeine Dependence Syndrome

This condition, as you may have guessed, is diagnosed when a person becomes dependent on caffeine. The problem is that there have been no population-based studies to investigate the prevalence or severity of within the general population.

It’s also quite difficult for practitioners to determine the root cause of caffeine addiction as many people that develop an addiction to caffeine have also developed other addictions to various drugs, illegal, prescription and over the counter. So it’s difficult to determine just exactly which type of individual could actually develop an addiction to caffeine.

Some studies have used the generic DSM-IV diagnostic criteria for Substance Abuse and applied this to caffeine. One study interviewed 104 healthy control subjects from the general population in Pisa, Italy and 6% of this group received a caffeine dependence diagnosis. If you scale that up to a larger population, you could argue that this is a rather large percentage of people to be diagnosed with an addiction to caffeine. [8]

Some people can feel euphoric when consuming caffeine, and as that feeling starts to dissipate, the brain can start to send signals to the user to consume more to get the same fix. So it’s very much like a drug of any other kind, it just so happens that the effects are on a much smaller scale, but still very noticeable.


Caffeine is a naturally occurring drug found in plants and used in many food and beverage products as well as cosmetic creams and health supplements.

Sensible usage is considered safe for most people, and mostly its effects will be beneficial (because who wants to start their Monday morning off without a strong up of coffee?).

It's recommend that you don't exceed 400mg of caffeine per day; certain people shouldn't consume it at all (children and pregnant women).

Contact your doctor if you have concerns about the effects of caffeine or its inclusion in your diet.

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