For healthy adults, up to 400 mg / day is considered a safe dose so as not to affect health.
Pregnant or lactating women are advised to consume no more than 200 mg / day. People with cardiovascular health problems should also consider limiting their caffeine intake .
Caffeine is naturally present in coffee, tea, cocoa, guarana, and yerba mate, but it is also frequently added to sodas, energy drinks, and weight loss supplements.
Most of us consume some form of caffeinated beverage. In 2016 alone, people ingested 7 million tons of coffee, and the energy drink market is constantly growing.
Before we get into the evidence on safe caffeine dosing, let’s see where all this caffeine comes from.
How much caffeine is in popular drinks?
Keep in mind that while the caffeine content of a particular energy drink or soda is constant from bottle to bottle, the caffeine content in it can vary greatly.
How much is too much caffeine?
The safety of caffeine is relative; It depends on the dose, of course, but also on your health. Some people show no unwanted symptoms from multiple cups of coffee per day, while others cannot drink one cup without experiencing:
- Abnormally high spikes in blood pressure
- Sleep disorders.
Generally, people experiencing caffeine withdrawal have reported similar symptoms, in addition to:
- Drowsiness / heaviness
- Less motivation to work.
- Concentration problems.
- Impaired cognitive performance.
- Flu-like symptoms.
- Muscular stiffness.
For healthy adults
Some food safety and science academies have concluded that, for healthy adults, caffeine intake of up to 400 mg / day does not pose general health concerns.
While you can consume more, 400 mg is the amount of caffeine that most healthy people can consume regularly in one day without undue side effects.
It is also indicated that, for most people, up to 200 mg of caffeine at a time does not pose health problems, even “when consumed less than two hours before intense physical exercise.”
However, they caution that taking 100 mg of caffeine near bedtime can affect your quality of sleep.
Keep in mind that the half-life of caffeine is 5 hours (on average it varies a lot between people), which means you probably still have caffeine in your blood if you drank coffee in the last 10 hours.
So healthy adults can safely consume up to 400mg / day, but avoid caffeine near bedtime for optimal sleep quality.
For breastfeeding or pregnant women
It is recommended by previous expert research reviews that women who are breastfeeding, pregnant, or planning to become pregnant limit their intake to 200 mg of caffeine per day.
Other reviews have concluded that 300mg / day is safe, but you may be cutting it off, as taking more increases your risk of nausea and worse, miscarriage.
Randomized controlled trials in pregnant or lactating women are scarce.
In this sense, less caffeine consumption may be prudent, especially since the half-life of caffeine increases from an average of 3 hours for non-pregnant women to 10.5 hours during the last 4 weeks of pregnancy.
In other words, when you’re pregnant, it takes a lot longer for your body to get rid of the caffeine you consume – some of the caffeine you eat in the morning is added to the caffeine you eat after lunch, so you can finish with a dose much higher running through your body than you ever thought possible.
Scientific reviews differ on what constitutes a safe maximum intake for pregnant or lactating women: 200 or 300 mg of caffeine per day. As the clinical evidence is scarce, it is advisable to keep consumption on the lower side of these recommendations.
For children and teenagers
Food safety agencies note that “the information available is insufficient to derive a safe intake of caffeine” for children and adolescents.
That is why it recommends using the upper limit of the adult population for single doses (3 mg per kilogram of body weight) as the upper daily limit of the youngest population consumption. Other experts, however, have called for a lower upper limit: 2.5 mg / kg / day.
According to some specialists, these doses would be that 2.5 mg / kg / day translates into the following approximate limits:
- 4-6 years: 45 mg / day.
- From 7-9 years: 62.5 mg / day.
- 10-12 years old: 85 mg / day.
Other groups have called for even more research and caution in this population, especially when it comes to the caffeine content of energy drinks.
An Institute of Medicine has recommended that caffeinated beverages not be sold to children at school.
In March 2013, a group of scientists sent a letter to the FDA commissioner stating that the best available scientific evidence demonstrates a strong correlation between caffeine levels in energy drinks and adverse health and safety consequences.
This is particularly true for children, adolescents, and young adults.
Therefore, the safe level of caffeine intake for children and adolescents is currently believed to be 2.5 or 3 mg / kg / day, but several organizations have called for more research in this area. Until more data can be collected, it is advisable to limit caffeine consumption in children.
For people with cardiovascular health problems
It is well documented that caffeine can raise blood pressure for 3-4 hours (although this effect normally diminishes with regular intake).
Fortunately, in healthy adults, caffeine intakes of up to 400 mg / day have not been linked to increases in cardiovascular risk.
But in people with high blood pressure or pre-existing heart conditions (in other words, in people for whom stimulants are generally contraindicated), the long-term effects of regular caffeine intake are less certain.
Moderate consumption may be fine, but this should be evaluated on a case-by-case basis in consultation with a healthcare provider.
The cardiovascular risk of healthy adults does not appear to increase with caffeine intake of up to 400 mg / day.
However, in people with high blood pressure or heart health problems, the long-term implications of regular caffeine intake are less clear: low to moderate intake might be safe, but consult your healthcare provider first.
How much can I drink before reaching the 400 mg limit?
To track your caffeine intake, you need to know the caffeinated beverages you drink and their caffeine content.
What happens if I eat too much caffeine?
Regarding oral doses of caffeine, 15 mg of caffeine per kg of body weight is considered toxic and 150 mg / kg can be lethal.
So for someone who weighs 68 kg (150 lb), toxicity starts at 1 g and lethality starts at 10 g. So yes, caffeine can kill, but a healthy person would need to drink dozens of the drinks shown above in quick succession.
Powdered caffeine is another story. The FDA advises that “one teaspoon of pure powdered caffeine is equal to the amount of caffeine in approximately 28 cups of regular coffee.” It is much easier to accidentally overdose on caffeine powder than in caffeinated beverages.
While poisonings or deaths caused by caffeine are rare, they do happen.
Even specialists can make mistakes, as seen in a university trial that accidentally gave two students 30 g of caffeine powder (equivalent to 300 cups of coffee), when they should have received 0.3 g (300 mg).
Both students survived, but were hospitalized for a time.
So unless you have a pre-existing heart condition, you’re at little risk of accidentally ingesting lethal doses of caffeine through caffeinated beverages, but you should stay away from powdered caffeine.
Apply best practices
The higher recommended intakes covered in this article are based on the long-term effects of regular caffeine consumption. Doses greater than 400 mg (up to 800 mg) have been used in short-term studies on the performance-enhancing effects of caffeine.
These high doses may not hurt when taken on occasion, depending on the person, but the more frequent the occasion, the more likely they are to experience the drawbacks of caffeine.
Also, some of the benefits of caffeine fade with frequent intake, which is why some people opt for the caffeine cycle.
The occasional high dose of caffeine can boost your physical performance, but regularly exceeding your recommended maximum intake can harm your long-term health.
On the other hand, regular and infrequent use of caffeine offer different benefits, so cycling caffeine may be wise, depending on your fitness goals.