Rockstar Pure Zero Energy Drink Caffeine Half-Life & Bedtime Decay
Rockstar Pure Zero delivers a heavy 240mg of caffeine per 16 fl oz can—50% more caffeine than standard Monster or Red Bull—with zero grams of sugar and zero calories.
Interactive Stack Calculator for Rockstar Pure Zero Energy Drink
We've preloaded Rockstar Pure Zero Energy Drink (240mg) below. Adjust your planned bedtime or add other drinks to see your exact curve.
Caffeine Half-Life & Cutoff Calculator
Caffeine's half-life ranges from about 4 to 7 hours depending on how fast you metabolise it. Add what you've already drunk today to find the last time your next drink still leaves under 50 mg in your system at bedtime.
Caffeine Sensitivity
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Last safe 240 mg drink
For this drink size, the safe window closed earlier today. A smaller drink, or decaf, may still fit.
Today's drinks alone leave about 36 mg at bedtime.
Solid: caffeine from today's drinks.
Stop guessing your cutoff.
Here you type your drinks in. ARC does the same math from every drink you log in one tap, moves your last safe coffee the moment you log a cup, shows it as a live countdown, and tells you plainly when no cup fits any more.
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Rockstar Pure Zero Energy Drink Hour-by-Hour Caffeine Decay Table
Pharmacokinetic Decay (5.5h Half-Life)Exact milligrams of caffeine remaining in the bloodstream at 2-hour intervals if consumed at various times of day, based on an average human caffeine half-life of 5.5 hours. Target is less than 50mg active at 11:00 PM bedtime.
| Intake Time | +2 hrs | +4 hrs | +6 hrs | +8 hrs | +10 hrs | +12 hrs | At 11 PM Bed | Status |
|---|---|---|---|---|---|---|---|---|
| 08:00 AM | 187 mg | 145 mg | 113 mg | 88 mg | 68 mg | 53 mg | 36 mg | ✓ Sleep Safe |
| 12:00 PM (Noon) | 187 mg | 145 mg | 113 mg | 88 mg | 68 mg | 53 mg | 60 mg | ✕ Above 50mg |
| 02:00 PM | 187 mg | 145 mg | 113 mg | 88 mg | 68 mg | 53 mg | 77 mg | ✕ Above 50mg |
| 04:00 PM | 187 mg | 145 mg | 113 mg | 88 mg | 68 mg | 53 mg | 99 mg | ✕ Above 50mg |
Cutoff Recommendation: Cut off before 12:30 PM. 240mg requires over 12.5 hours to drop below 50mg.
Values are calculated using the standard exponential decay model: mg_remaining = initial_mg * 0.5^(hours / half_life).
How Your Genetics (CYP1A2) Impact Rockstar Pure Zero Energy Drink Clearance
Over 95% of caffeine metabolism takes place in your liver via the cytochrome P450 enzyme CYP1A2. Depending on whether you carry the fast or slow metabolizing gene variant, clearance times for 240mg vary drastically:
Residual after 8 hours: 60 mg. You clear caffeine rapidly and rarely experience insomnia from lunch beverages.
Residual after 8 hours: 88 mg. Standard biological decay rate representing ~50% of the population.
Residual after 8 hours: 109 mg. CYP1A2*1F carriers. Any caffeine consumed past noon will disrupt sleep architecture.
Frequently asked questions
How long does Rockstar Pure Zero stay active in your blood?
At 240mg, after 5.5 hours you still have 120mg in your bloodstream, and after 11 hours you still have 60mg. It requires nearly 13 hours to become sleep-safe.