Nutrition and Your Health: Is 390 mg a lot of caffeine?

October 28, 2025 •

4 min read

The U.S. Food and Drug Administration (FDA) suggests a daily caffeine intake limit of 400 mg for most healthy adults. This brings to question: is 390 mg a lot of caffeine for a typical person, and what are the potential health impacts?

Quick Summary

At 390 mg, caffeine intake approaches the maximum safe daily dose for healthy adults. This amount can cause negative side effects, particularly for those sensitive to caffeine or with underlying health conditions. Monitoring consumption from all sources is crucial.

Key Points

Near the Limit: 390 mg of caffeine is very close to the FDA's recommended 400 mg daily maximum for most healthy adults and should be considered a high dose.
Risks of High Consumption: Exceeding or approaching the maximum safe limit can lead to adverse effects, including increased heart rate, anxiety, insomnia, and digestive issues.
Individual Tolerance Varies: Personal sensitivity to caffeine differs based on genetics, body weight, and metabolism, meaning 390 mg could be dangerous for some.
Sources Add Up: Caffeine intake comes from multiple sources like coffee, energy drinks, tea, and some medications, and the total daily amount must be considered.
High-Risk Individuals: Pregnant women, those with heart conditions, anxiety disorders, or people on certain medications should be especially cautious or avoid high caffeine amounts.
Gradual Reduction: Reducing high caffeine intake gradually is recommended to minimize withdrawal symptoms such as headaches and fatigue.
Listen to Your Body: Paying attention to how your body reacts is the best way to determine your personal safe limit for caffeine consumption.

What is a Safe Daily Caffeine Intake?

For most healthy adults, a daily intake of up to 400 milligrams (mg) of caffeine is not generally associated with negative health effects. However, this is not a one-size-fits-all rule. A 390 mg dose is very close to this suggested maximum, making it a significant amount that requires careful consideration. It's important to recognize that individual tolerance to caffeine varies widely based on factors such as genetics, body weight, and metabolism. Some people can handle this amount without issue, while others may experience adverse effects from much smaller doses. A well-documented case involved a student with a heart condition who experienced cardiac arrest after consuming a highly caffeinated lemonade containing approximately 390 mg. This tragic event underscores the need for individuals to be aware of their personal limits and potential health risks.

The Potential Health Impacts of 390 mg of Caffeine

Consuming a dose of caffeine close to the 400 mg daily limit can trigger several side effects. These are often more pronounced in individuals who are sensitive to caffeine or who consume this amount on an empty stomach. Potential health impacts include:

Central Nervous System Stimulation: While this can lead to increased alertness, excessive stimulation can cause restlessness, shakiness, or jitters.
Cardiovascular Effects: High doses can lead to an increased heart rate, palpitations, and elevated blood pressure. For individuals with pre-existing heart conditions, this can pose a serious risk.
Sleep Disruption: Caffeine's stimulating effects can interfere with your sleep cycle, making it difficult to fall and stay asleep. This can become a cycle where a person consumes more caffeine to combat daytime fatigue.
Digestive Issues: Caffeine can increase stomach acid, leading to upset stomach, heartburn, or diarrhea.
Anxiety and Irritability: The overstimulation of the central nervous system can exacerbate symptoms of anxiety disorders.
Urinary Effects: As a diuretic, caffeine increases the frequency of urination, which can lead to dehydration if not balanced with adequate water intake.

The cumulative effect of caffeine

When considering if 390 mg is too much, it's crucial to account for all sources of caffeine throughout the day, not just one drink. Many people don't realize how quickly caffeine can add up from various foods and beverages.


Source	Serving Size	Approx. Caffeine Content
Coffee (brewed)	8 oz	96 mg
Espresso (double shot)	1.5 oz	150 mg
Standard Energy Drink	16 oz	160 mg
Starbucks Venti Brewed Coffee	20 oz	390–490 mg
Panera Charged Lemonade	30 oz	~390 mg
Brewed Black Tea	8 oz	47 mg
Cola Soda	12 oz	34 mg

Who Should Be Especially Cautious?

While 390 mg is high for even a healthy adult, certain individuals need to be particularly careful with their caffeine intake. These groups are more susceptible to the adverse effects of caffeine.

Pregnant and Breastfeeding Women: High caffeine consumption is potentially unsafe during pregnancy and breastfeeding, with recommendations often under 200–300 mg daily.
Children and Adolescents: Health experts advise children and teens to avoid energy drinks and limit caffeine significantly due to their greater sensitivity.
Individuals with Heart Conditions: Those with high blood pressure, arrhythmias, or other heart conditions should use caffeine with caution as it can increase heart rate and blood pressure.
People with Anxiety Disorders: Caffeine can worsen symptoms of anxiety, restlessness, and panic attacks.
Individuals Taking Certain Medications: Caffeine can interact with a wide range of medications, including certain antibiotics, heart medicines, and stimulants.
People with Insomnia: Caffeine can disrupt sleep patterns, and those with pre-existing sleep disorders should be mindful of their intake.

Managing High Caffeine Intake

If you find your daily intake is too high, especially if you are consuming 390 mg or more, it's wise to reduce it. Abruptly stopping can cause withdrawal symptoms like headaches, fatigue, and irritability. A gradual approach is often recommended.

Strategies to reduce caffeine intake:

Taper Off Slowly: Gradually decrease your daily consumption by a small percentage over several weeks. For example, if you drink four cups of coffee, reduce to three for a week, then two, and so on.
Stay Hydrated: Drink plenty of water throughout the day. Dehydration can worsen symptoms associated with caffeine and withdrawal.
Find Alternative Beverages: Replace some caffeinated drinks with decaf options or herbal teas. Note that decaf products still contain a small amount of caffeine.
Increase Physical Activity: Exercise is a natural energy booster and can help counteract feelings of fatigue during withdrawal.
Prioritize Sleep: Improve your sleep hygiene to rely less on caffeine to stay alert during the day.

Conclusion

So, is 390 mg a lot of caffeine? For the vast majority of people, the answer is yes. While technically just under the 400 mg daily guideline for most healthy adults, it is a very high dose. The risks of negative side effects increase significantly at this level, and individual sensitivity can make it a dangerous amount for many. To ensure a healthier nutrition plan, it is crucial to monitor your total intake from all sources, understand your personal tolerance, and seek healthier alternatives when needed. Listening to your body is the most important rule for safe caffeine consumption.

Learn more about safe caffeine consumption from the FDA.

Frequently Asked Questions

Consuming too much caffeine can lead to restlessness, insomnia, anxiety, a rapid heart rate, headaches, upset stomach, and shakiness. More severe symptoms in case of overdose include confusion, vomiting, and heart rhythm disturbances.

Most healthy adults can safely consume up to 400 mg of caffeine per day. This is roughly equivalent to four 8-ounce cups of coffee, but individual tolerance and other caffeine sources must be considered.

Yes, regular, high-dose caffeine intake can lead to tolerance, requiring a person to consume more to achieve the same stimulating effects. This can make a caffeine reset necessary to regain sensitivity.

Besides coffee and energy drinks, caffeine can be found in a variety of other products, including tea, chocolate, some over-the-counter pain relievers (like Excedrin), certain dietary supplements, and even decaffeinated coffee.

It is best to reduce your caffeine intake gradually to minimize withdrawal symptoms. You can slowly taper down your daily amount, switch to decaf or herbal teas, stay hydrated with water, and prioritize better sleep and exercise.

Individuals who are pregnant or breastfeeding, children and adolescents, and people with heart conditions, anxiety disorders, insomnia, or peptic ulcers should avoid caffeine. Those taking certain medications should also consult a healthcare provider.

To minimize the effects, you can drink water to stay hydrated, engage in light physical activity like a walk, and practice deep breathing to calm down. If symptoms are severe, like a racing heart or confusion, seek immediate medical help.