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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 Bottom Line – Caffeine is a stimulant found in plants and it can also be artificially created. It is usually consumed to increase alertness and prevent tiredness.

Caffeine Health Benefits

Caffeine is often added to consumer products such as drinks and energy bars for weight loss and increased alertness; it has also been found to improve memory.

Below is a list of the possible benefits we’ve found:

Can Help With Memory Loss Prevention

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]

Caffeine Can Help With 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. [3][4]

Caffeine Can Help With Weight Loss

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

Caffeine Can Help With Preventing 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. 

The Bottom Line – Caffeine has been found to be useful for some people while losing weight, as well as for preventing hair loss and in age-related chronic inflammation.

How To Use Caffeine

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 an anti-fatigue supplements)
  • As a cream (in cosmetic face and anti-cellulite creams)
  • As an ingredient in protein shakes and bars (for weight loss or weight gain prevention)

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.

Are There Any Foods That Contain Caffeine?

There are plenty of foods that contain caffeine, both naturally and as an added ingredient.

Foods that contain caffeine include coffee, chocolate (and coffee or chocolate flavoured ice-cream and yogurt); breakfast cereals; sodas such as Coca-Cola; protein bars and shakes and energy drinks or bars.

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.

Is Caffeine Safe?

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.

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.

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.

When Should I Not Take Caffeine?

  • 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.

Has Caffeine Been Linked To Any Deaths?

Caffeine has been linked to several deaths including teenagers who took large amounts of caffeine pills, a woman who died from taking caffeine-containing diet pills and several adults who died after consuming large quantities of canned energy drink.

The Bottom Line – Caffeine is used widely and is generally safe to consume within recommended limits. It can in large quantities be damaging to health and occasionally fatal.


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

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Fact Checked

This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.