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Red Bull (250ml / 8.4oz)

Caffeine Half-Life Analysis

For: Healthy Adult
80
mg Caffeine
5.0
Hour Half-Life
~N/A
Hours to Sleep-Safe
400
mg Daily Limit

trending_down Caffeine Decay Timeline

How 80mg caffeine clears from your system with a 5.0-hour half-life

Time Elapsed Caffeine Remaining % of Original Status
Now (consumption) 80.0 mg
100.0% 		Moderate
After 1 hour 69.6 mg
87.1% 		Moderate
After 2 hours 60.6 mg
75.8% 		Moderate
After 3 hours 52.8 mg
66.0% 		Moderate
After 4 hours 45.9 mg
57.4% 		Minimal
After 5 hours 40.0 mg
50.0% 		Minimal
After 6 hours 34.8 mg
43.5% 		Minimal
After 8 hours 26.4 mg
33.0% 		Minimal
After 10 hours 20.0 mg
25.0% 		Minimal
After 12 hours 15.2 mg
18.9% 		Minimal
After 16 hours 8.7 mg
10.9% 		Cleared
After 20 hours 5.0 mg
6.2% 		Cleared
After 24 hours 2.9 mg
3.6% 		Cleared

health_and_safety Health Insights for Healthy Adult

ℹ️ Health Note

The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains.

Daily Limit Calculation

  • • Recommended daily limit: 400mg of caffeine
  • • Caffeine per serving: 80mg
  • • Servings until limit: 5.0 servings

Limit caffeine intake to 400mg/day. Avoid consumption within 6-8 hours of bedtime for optimal sleep.

Sleep Quality Impact

Caffeine blocks adenosine receptors in the brain, preventing the buildup of sleep pressure. Even when you don't feel "wired," residual caffeine can reduce deep sleep quality by up to 20%.

>100mg
May disrupt sleep
50-100mg
Reduced deep sleep
<50mg
Minimal impact

science How Caffeine Half-Life Works

Half-life is the time required for the body to eliminate 50% of a substance. For caffeine, this primarily occurs in the liver through the CYP1A2 enzyme system.

With a half-life of 5.0 hours for healthy adult, caffeine follows exponential decay:

  • After 5.0 hours: 50% remains (40.0mg)
  • After 10.0 hours: 25% remains (20.0mg)
  • After 15.0 hours: 12.5% remains (10.0mg)
  • After 20.0 hours: 6.25% remains (5.0mg)

The healthy adult category has a average metabolism compared to healthy adults (5 hours baseline). The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains.

Compare Other Drinks

Brewed Coffee (240ml / 8oz) 95mg Espresso (30ml / 1oz shot) 63mg Monster Energy (473ml / 16oz) 160mg Green Tea (240ml / 8oz) 28mg

Compare Conditions

Smokers 3.0h Pregnancy 10.5h Birth Control Users 7.5h Liver Impairment 12.0h Elderly (65+) 6.5h Fast Metabolizers (Genetic) 3.5h

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About Red Bull (250ml / 8.4oz)

Popular energy drink

Note: Also contains taurine, B-vitamins, and 27g of sugar

help Frequently Asked Questions

How long does Red Bull (250ml / 8.4oz) caffeine last for healthy adult?

For healthy adult, the caffeine half-life is approximately 5.0 hours. This means that 80mg of caffeine from Red Bull (250ml / 8.4oz) will take about 5.0 hours to reduce to 40mg, and 10.0 hours to drop to 20mg. Full clearance (below 10mg) takes approximately 15.0 hours.

When should I stop drinking Red Bull (250ml / 8.4oz) to sleep well?

If you plan to sleep at 10 PM, you should consume your last Red Bull (250ml / 8.4oz) by any time - caffeine level is low. This allows approximately sufficient hours for caffeine levels to drop below the sleep disruption threshold of 100mg.

How does being in the 'Healthy Adult' category affect caffeine metabolism?

The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains. Limit caffeine intake to 400mg/day. Avoid consumption within 6-8 hours of bedtime for optimal sleep.