Blog
Tips, science, and updates from the Koffee team.
The Best Time to Drink Coffee, According to Your Cortisol Rhythm
Drinking coffee during your cortisol peak is like stacking stimulants. Here's when to time your cups for maximum energy with minimum side effects.
Caffeine and Anxiety: How Coffee Can Trigger (or Worsen) Panic
Caffeine blocks your brain's calming signals and triggers fight-or-flight. Here's the science of caffeine-induced anxiety and what you can do about it.
Caffeine and Sleep: How Coffee Actually Disrupts Your Rest (Even When You Think It Doesn't)
Caffeine doesn't just keep you awake. It dismantles your sleep architecture from the inside, reducing deep sleep and REM even when you fall asleep on time. Here's the full science.
Caffeine During Pregnancy: How Much Is Safe, What the Research Says, and How to Cut Back
Most doctors say 200mg of caffeine per day is safe during pregnancy, but the research is more nuanced than that. Here's everything you need to know about coffee while pregnant.
Caffeine Withdrawal: Symptoms, Timeline, and How to Get Through It
Headaches, fatigue, brain fog — caffeine withdrawal is real. Here's exactly what to expect day by day, and how to minimize the pain.
How Long Does Caffeine Last? The Complete Science of Caffeine Duration
Caffeine doesn't just disappear after a few hours. Here's exactly how long it stays in your system, what determines its duration, and why the answer is different for everyone.
When Should You Stop Drinking Coffee? Your Personal Last Call
The generic 'no coffee after 2pm' rule doesn't work for everyone. Here's how to find your personal caffeine cutoff time based on your metabolism and bedtime.
Best Caffeine Tracker Apps in 2026: Honest Comparison
We compare the top caffeine tracker apps for iPhone and Android — features, accuracy, and which one actually helps you sleep better.
How Much Caffeine Is Too Much? (The Answer Is Personal)
The FDA says 400mg, but your real limit depends on your weight, genetics, and what time you drink it. Here's how to find your number.
How to Reset Your Caffeine Tolerance: The Complete Protocol
Caffeine stopped working? Here's a science-backed protocol to reset your tolerance in 7-14 days — and how to keep it from building back up.
Caffeine Metabolism: Are You a Fast or Slow Metabolizer?
Your CYP1A2 gene determines how fast you process caffeine. Here's what that means for your coffee habits, sleep, and health.
Espresso vs Coffee: Which Actually Has More Caffeine?
Espresso is more concentrated, but a regular cup of coffee has more total caffeine. Here's the complete breakdown by drink type.
How Much Caffeine Is in Decaf Coffee? (It's Not Zero)
Decaf coffee still contains 2-15mg of caffeine per cup. Here's why that matters, especially if you're caffeine-sensitive.