Does Coffee on an Empty Stomach Increase Cortisol?

November 16, 2025 •

4 min read

According to a 2024 study, habitual caffeine use was associated with heightened cortisol reactivity, sparking debate on morning coffee routines. While many believe drinking coffee on an empty stomach increases cortisol significantly, the reality is more nuanced and depends on several factors, including individual tolerance and timing.

Quick Summary

Drinking coffee can cause a temporary cortisol spike, but the effect on an empty stomach is highly individual and often minimal for regular drinkers. Timing your coffee with your body's natural cycle and consuming it with food can help mitigate any potential negative impacts on stress hormones and digestion.

Key Points

Nuanced Reality: For most people, the increase in cortisol from drinking coffee on an empty stomach is minimal and temporary, especially for regular caffeine consumers.
Individual Sensitivity is Key: Personal tolerance and genetics heavily influence the effect of coffee and caffeine on an individual's hormones and stress levels.
Timing Matters for Optimization: Waiting 60-90 minutes after waking up to have coffee can align with the body's natural cortisol cycle for a smoother energy boost.
Digestive Concerns are Separate: Potential side effects like stomach irritation, acid reflux, and altered motility are more significant risks of empty-stomach coffee for sensitive individuals.
Mitigate Spikes with Food: Consuming a balanced breakfast with protein and fat alongside coffee can help buffer the caffeine's impact on cortisol and blood sugar.
Avoid the Afternoon Crash: Limiting caffeine consumption to the morning can help prevent disrupted sleep patterns and the energy crash associated with elevated cortisol.
Hydrate First: Starting your day with water is crucial, as coffee is a diuretic and dehydration can also be a source of stress on the body.

Understanding Cortisol and Your Morning Rhythm

Cortisol is a steroid hormone produced by your adrenal glands, often called the 'stress hormone'. It is essential for regulating metabolism, blood pressure, and managing the body's response to stress. Interestingly, cortisol follows a natural circadian rhythm, peaking in the morning to help you wake up and then gradually declining throughout the day.

The popular claim is that adding coffee to this natural morning peak can cause a problematic and unnatural spike. However, research shows this isn't the full picture. For regular coffee drinkers, the body develops a tolerance, and the cortisol response to caffeine is often much lower or non-existent. Acute caffeine intake, especially for non-habitual users or in high doses, can indeed increase cortisol levels temporarily, but the long-term health consequences of this brief spike are considered minimal for most healthy individuals.

The Empty Stomach Factor and Digestion

While the cortisol spike from coffee might not be as dramatic as some social media trends suggest, drinking it on an empty stomach presents other potential concerns, primarily related to digestion. Coffee's bitterness stimulates stomach acid production, which can be irritating for those with sensitive stomachs or pre-existing conditions like acid reflux, GERD, or IBS.

Increased Gastric Acidity: For sensitive individuals, coffee stimulates hydrochloric acid, which can cause heartburn or gastritis without food to buffer it.
Intestinal Motility: Caffeine can increase colon motility, potentially leading to digestive discomfort, bloating, or cramping, especially on an empty stomach.
Individual Sensitivity: Responses vary widely. Some people can drink coffee on an empty stomach without any issues, while others find it causes discomfort.

Comparison: Coffee with Food vs. Coffee on an Empty Stomach


Feature	Coffee on an Empty Stomach	Coffee with Food
Cortisol Response	Can amplify the natural morning spike, especially for irregular users. Acute, temporary increase possible.	Food can help buffer the cortisol response from caffeine.
Digestive Impact	May cause irritation, heartburn, or acid reflux for sensitive individuals due to increased stomach acid.	Food provides a buffer against stomach acid, reducing the risk of digestive issues.
Blood Sugar Levels	Can cause a sharper blood sugar spike followed by a crash, particularly with sugary coffee.	A balanced meal with protein and healthy fats helps stabilize blood sugar, mitigating sharp spikes.
Energy Level	Initial sharp jolt of energy, but can lead to a more pronounced "crash" later on.	Provides a more sustained and balanced energy release throughout the morning.

The Optimal Coffee Timing for Cortisol Management

For those concerned about managing cortisol levels and avoiding potential side effects, timing can be key. Neuroscientists and health experts often suggest waiting to have your first cup of coffee until after the body's natural morning cortisol peak has subsided.

Wait 60-90 Minutes: Your cortisol naturally peaks 30-45 minutes after waking up. By waiting at least an hour, you allow your body to use its natural alertness and avoid adding a redundant jolt of caffeine.
Stay Hydrated: Start your day with a tall glass of water. Coffee is a diuretic, so hydrating first is crucial for overall energy levels.
Eat a Balanced Breakfast: Pairing your coffee with a meal containing protein and healthy fats can help stabilize blood sugar and buffer any cortisol response.
Listen to Your Body: If you feel jittery, anxious, or experience digestive issues, it may be a sign you are sensitive to caffeine or need to adjust your timing.

Chronic Cortisol Elevation and Beyond

While a single cup of coffee is unlikely to cause significant harm, chronic and excessive caffeine intake, particularly when combined with high levels of stress, can contribute to persistently elevated cortisol. Chronically high cortisol can lead to negative health outcomes such as weight gain, disrupted sleep, and increased anxiety. Therefore, for individuals managing these conditions, adjusting coffee intake and timing is a sensible strategy.

Conclusion: A Balanced Perspective on Coffee and Cortisol

Scientific evidence suggests that while coffee can temporarily increase cortisol, the effect is often minor for regular consumers and not necessarily detrimental, even on an empty stomach. Concerns surrounding digestive issues and blood sugar regulation are more prominent potential side effects of consuming coffee on an empty stomach, particularly for sensitive individuals. The notion that morning coffee on an empty stomach is universally harmful is more of a myth than a fact. By paying attention to your body's individual response, timing your intake strategically, and pairing your coffee with a nutritious breakfast, you can enjoy your brew without unnecessary stress on your system. The best approach is a mindful one, prioritizing overall health and well-being rather than following rigid, one-size-fits-all rules.

Authoritative link example: The National Institutes of Health provides insights into caffeine and its effects on the body.

Frequently Asked Questions

For most healthy people, it is not inherently harmful. However, some individuals with sensitive stomachs may experience digestive issues like heartburn or irritation due to increased stomach acid.

The ideal time to drink coffee is typically 60-90 minutes after waking, when the body's natural morning cortisol peak has started to decline.

Decaf coffee contains minimal caffeine but can still cause a modest, though less pronounced, increase in cortisol compared to regular coffee. This is likely due to non-caffeine factors associated with the coffee ritual.

To minimize caffeine's effect on cortisol, you can delay your first cup by 60-90 minutes, have it with a balanced meal, and ensure you are well-hydrated by drinking water first.

Chronic, excessively high cortisol levels can be linked to weight gain, particularly in the abdominal area. While moderate coffee is unlikely to cause this, excessive and poorly timed intake, combined with stress, could contribute over time.

Signs of elevated cortisol from caffeine can include jitters, anxiety, restlessness, heart palpitations, and an increased sense of being overwhelmed or 'wired but tired'.

Individuals with anxiety disorders, adrenal issues, or hormonal imbalances may be more sensitive to caffeine and its effect on cortisol. They may benefit from moderating intake or adjusting timing.