coffee

Brewed Coffee (240ml / 8oz)

Caffeine Half-Life Analysis

For: Birth Control Users
95
mg Caffeine
7.5
Hour Half-Life
~N/A
Hours to Sleep-Safe
400
mg Daily Limit

trending_down Caffeine Decay Timeline

How 95mg caffeine clears from your system with a 7.5-hour half-life

Time Elapsed Caffeine Remaining % of Original Status
Now (consumption) 95.0 mg
100.0% 		Moderate
After 1 hour 86.6 mg
91.2% 		Moderate
After 2 hours 79.0 mg
83.1% 		Moderate
After 3 hours 72.0 mg
75.8% 		Moderate
After 4 hours 65.6 mg
69.1% 		Moderate
After 5 hours 59.8 mg
63.0% 		Moderate
After 6 hours 54.6 mg
57.4% 		Moderate
After 8 hours 45.4 mg
47.7% 		Minimal
After 10 hours 37.7 mg
39.7% 		Minimal
After 12 hours 31.3 mg
33.0% 		Minimal
After 16 hours 21.7 mg
22.8% 		Minimal
After 20 hours 15.0 mg
15.7% 		Minimal
After 24 hours 10.3 mg
10.9% 		Minimal

health_and_safety Health Insights for Birth Control Users

⚠️ Important Health Consideration

Estrogen in birth control pills inhibits CYP1A2 enzymes, extending caffeine's half-life by 30-50%. This effect is more pronounced with higher estrogen doses.

Daily Limit Calculation

  • • Recommended daily limit: 400mg of caffeine
  • • Caffeine per serving: 95mg
  • • Servings until limit: 4.2 servings

Reduce afternoon caffeine intake. The same amount of coffee will have a stronger, longer-lasting effect.

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 7.5 hours for birth control users, caffeine follows exponential decay:

  • After 7.5 hours: 50% remains (47.5mg)
  • After 15.0 hours: 25% remains (23.75mg)
  • After 22.5 hours: 12.5% remains (11.875mg)
  • After 30.0 hours: 6.25% remains (5.9375mg)

The birth control users category has a slower metabolism compared to healthy adults (5 hours baseline). Estrogen in birth control pills inhibits CYP1A2 enzymes, extending caffeine's half-life by 30-50%. This effect is more pronounced with higher estrogen doses.

warning Please Note

Reduce afternoon caffeine intake. The same amount of coffee will have a stronger, longer-lasting effect.

Compare Other Drinks

Espresso (30ml / 1oz shot) 63mg Red Bull (250ml / 8.4oz) 80mg Monster Energy (473ml / 16oz) 160mg Green Tea (240ml / 8oz) 28mg

Compare Conditions

Healthy Adult 5.0h Smokers 3.0h Pregnancy 10.5h Liver Impairment 12.0h Elderly (65+) 6.5h Fast Metabolizers (Genetic) 3.5h

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About Brewed Coffee (240ml / 8oz)

Standard drip-brewed coffee

Note: Caffeine can range from 70-140mg depending on brewing method and bean origin

help Frequently Asked Questions

How long does Brewed Coffee (240ml / 8oz) caffeine last for birth control users?

For birth control users, the caffeine half-life is approximately 7.5 hours. This means that 95mg of caffeine from Brewed Coffee (240ml / 8oz) will take about 7.5 hours to reduce to 48mg, and 15.0 hours to drop to 24mg. Full clearance (below 10mg) takes approximately 24.4 hours.

When should I stop drinking Brewed Coffee (240ml / 8oz) to sleep well?

If you plan to sleep at 10 PM, you should consume your last Brewed Coffee (240ml / 8oz) 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 'Birth Control Users' category affect caffeine metabolism?

Estrogen in birth control pills inhibits CYP1A2 enzymes, extending caffeine's half-life by 30-50%. This effect is more pronounced with higher estrogen doses. Reduce afternoon caffeine intake. The same amount of coffee will have a stronger, longer-lasting effect.