Caffeine vs WaterEnergy drinks
Energy Drinks and Sleep: 23 Cans Ranked by How Long They Keep You Up
Energy drinks and sleep don't mix late in the day, but some cans are far worse than others. We ranked 23 energy drinks by the hours they need before bed.
The short answer
- A small Red Bull (80 mg) needs about 4 hours to fall under 50 mg, so finish it by 7 pm for an 11 pm bedtime.
- A 16 oz Monster (160 mg) needs about 9.5 hours: stop by 1:30 pm.
- A 200 mg can (Celsius, Alani Nu, Ghost, C4, 5-hour Energy) needs about 11 hours: stop by noon.
- A 300 mg can (Bang, Reign, Celsius Heat) needs about 14.5 hours. For an 11 pm bedtime, that means before 8:30 am.
Energy drinks and sleep have a simple relationship: the more caffeine in the can, the earlier in the day it has to be. The problem is that energy drinks vary more than any other caffeinated drink. The weakest cans have less caffeine than a cup of tea. The strongest have more than three cups of coffee.
So "no energy drinks after 3 pm" is not much use on its own. We ranked 23 popular energy drinks by how long each one takes to fall under 50 mg of active caffeine, using the same caffeine model as our app. The 50 mg line is a sensible bedtime target: it's about half a cup of coffee, and roughly where sleep studies stop finding a clear effect.
Energy drinks and sleep: what the research says
Energy drinks don't have a special sleep-wrecking ingredient. The main effect on sleep comes from caffeine, which blocks adenosine, the chemical that builds sleep pressure through the day. What makes energy drinks different is the dose, and the fact that many people drink them in the afternoon or evening to push through a shift, a workout or a study session.
The evidence on caffeine and sleep is clear:
- A 2023 meta-analysis of 24 studies found caffeine cut total sleep by about 45 minutes and reduced deep sleep. It calculated that a 217.5 mg pre-workout-sized dose should be taken at least 13.2 hours before bed.
- In a 2025 trial, 400 mg of caffeine delayed sleep even when taken 12 hours before bed, while 100 mg had no significant effect, even at 4 hours. People also underestimated how much their sleep had suffered.
- A national survey of more than 53,000 Norwegian students found that those who drank energy drinks daily were about twice as likely to sleep less than 6 hours. Even occasional use was linked to poorer sleep. It's a survey, so it can't prove cause, but the pattern matches the lab studies.
In short: a small can early in the day is unlikely to matter much. A big can after lunch almost certainly does. (For the mechanism, including why you can "sleep fine" and still wake up tired, see how caffeine affects sleep.)
Energy drinks ranked by bedtime cutoff
Hours needed for one can to drop under 50 mg, at three half-lives: fast (4 h), typical (5.5 h) and slow (7.5 h, the app's "Hits me hard" preset). The last column is the latest time to finish the can for an 11 pm bedtime at a typical half-life. Caffeine figures match the drink catalog in Caffeine vs Water.
| Energy drink | Caffeine | Fast | Typical | Slow | Last can, 11 pm bed |
|---|---|---|---|---|---|
| Red Bull Simply Cola, 250 ml | 32 mg | any time | any time | any time | any time |
| Lucozade Energy, 380 ml | 46 mg | any time | any time | any time | any time |
| V Energy, 250 ml | 78 mg | 3 h | 4 h | 5 h | 7 pm |
| Red Bull, 8.4 oz / 250 ml | 80 mg | 3 h | 4 h | 5.5 h | 7 pm |
| Red Bull, 12 oz / 355 ml | 114 mg | 5 h | 7 h | 9 h | 4 pm |
| Starbucks Energy Refresher, Grande 16 oz | 125 mg | 5.5 h | 7.5 h | 10 h | 3:30 pm |
| Monster Zero Ultra, 16 oz | 150 mg | 6.5 h | 9 h | 12 h | 2 pm |
| Red Bull, 16 oz / 473 ml | 151 mg | 6.5 h | 9 h | 12 h | 2 pm |
| Monster Energy, 16 oz / 473 ml | 160 mg | 7 h | 9.5 h | 13 h | 1:30 pm |
| Rockstar, 16 oz | 160 mg | 7 h | 9.5 h | 13 h | 1:30 pm |
| Red Bull, 20 oz / 591 ml | 198 mg | 8 h | 11 h | 15 h | noon |
| Celsius, 12 oz / 355 ml | 200 mg | 8 h | 11 h | 15 h | noon |
| Alani Nu Energy, 12 oz | 200 mg | 8 h | 11 h | 15 h | noon |
| Ghost Energy, 16 oz | 200 mg | 8 h | 11 h | 15 h | noon |
| C4 Energy, 16 oz | 200 mg | 8 h | 11 h | 15 h | noon |
| 5-hour Energy, 1.93 oz / 57 ml | 200 mg | 8 h | 11 h | 15 h | noon |
| Monster Energy, 24 oz / 710 ml | 240 mg | 9.5 h | 12.5 h | 17 h | 10:30 am |
| Celsius Essentials, 16 oz | 270 mg | 10 h | 13.5 h | 18.5 h | 9:30 am |
| Bang, 16 oz | 300 mg | 10.5 h | 14.5 h | 19.5 h | 8:30 am |
| Reign, 16 oz | 300 mg | 10.5 h | 14.5 h | 19.5 h | 8:30 am |
| Celsius Heat, 16 oz | 300 mg | 10.5 h | 14.5 h | 19.5 h | 8:30 am |
| Redline Xtreme, 8 oz | 316 mg | 11 h | 15 h | 20 h | 8 am |
| Rockstar XDurance, 24 oz | 400 mg | 12 h | 16.5 h | 22.5 h | 6:30 am |
The ranking is really a ranking by caffeine. Sugar, taurine and B vitamins don't change the timing, which is why a Red Bull 16 oz and a Monster Zero Ultra land in the same place. What changes everything is the size of the can: a Red Bull goes from a 7 pm cutoff in the 8.4 oz can to noon in the 20 oz. (For side-by-side caffeine by brand and flavor, see the energy drink caffeine comparison.)
What one can looks like over a day
Here's a 16 oz Monster (160 mg) at three half-lives. It peaks about 50 minutes after you finish it, then fades slowly. The dashed line is the 50 mg bedtime target.
Show as a table
| Half-life | 1 h | 3 h | 6 h | 9 h | 12 h | 24 h |
|---|---|---|---|---|---|---|
| 4 h | 138 | 99 | 59 | 35 | 21 | 3 |
| 5.5 h | 143 | 113 | 77 | 53 | 36 | 8 |
| 7.5 h | 147 | 124 | 94 | 71 | 54 | 18 |
mg of active caffeine, hours after one 160 mg drink.
A 3 pm Monster still leaves about 60 mg at 11 pm for a typical metaboliser. That's above the target, and it's the reason the "just one after work" can so often turns into a restless night.
Two cans are worse than you think
The table assumes one drink on its own. Caffeine from earlier cans is still in you when you open the next one:
- Two 16 oz Monsters at 9 am and 3 pm leave about 88 mg at 11 pm.
- Three small Red Bulls at 9 am, 1 pm and 5 pm leave about 76 mg at 11 pm, even though each one would be fine alone.
- One Bang at 2 pm leaves about 100 mg at 11 pm and about 36 mg when you wake up at 7 am.
That last point matters: with big cans, you start the next day with caffeine still on board, sleep less, feel worse, and reach for another can. If you drink more than one a day, how many energy drinks a day is safe covers the daily limits.
How to keep energy drinks and still sleep
- Match the can to the clock. Big cans (200 mg and up) belong in the morning. After lunch, drop to a small 8.4 oz can or something under 50 mg.
- Size down, not out. Swapping a 16 oz Red Bull for an 8.4 oz one moves your cutoff from 2 pm to 7 pm.
- Watch the pre-workout. An evening workout with a 200–300 mg scoop is the same as a 200–300 mg can. See hidden sources of caffeine.
- Count your own bedtime. The times above assume 11 pm. If you sleep at 10 pm, move every cutoff an hour earlier. If you work nights, see caffeine and shift work.
- Check your own cutoff with the bedtime caffeine calculator, or the caffeine cutoff guide if you also drink coffee.
In Caffeine vs Water, the day planner lets you add a can you're thinking about later and see your bedtime caffeine before you drink it.
Frequently asked questions
How long before bed should I stop drinking energy drinks?
It depends on the can. At a typical 5.5-hour half-life, an 8.4 oz Red Bull (80 mg) needs about 4 hours to fall under 50 mg, a 16 oz Monster (160 mg) about 9.5 hours, a 200 mg can such as Celsius about 11 hours, and a 300 mg can such as Bang about 14.5 hours.
Which energy drink is worst for sleep?
The ones with the most caffeine. Among popular cans, 300 mg drinks such as Bang, Reign and Celsius Heat, the 316 mg Redline Xtreme and the 400 mg 24 oz Rockstar XDurance need 14.5 hours or more to clear to 50 mg for a typical adult.
Does Monster keep you awake at night?
A 16 oz Monster has 160 mg of caffeine. Drunk at 3 pm, it leaves about 60 mg in a typical adult at 11 pm, above the 50 mg bedtime target. Drunk before about 1:30 pm, it should be under 50 mg by an 11 pm bedtime.
Can I drink a Red Bull before bed?
An 8.4 oz Red Bull has 80 mg of caffeine, which peaks about 50 minutes later. Right before bed it will almost certainly make it harder to fall asleep and reduce deep sleep. Aim to finish it at least 4 hours before bed, or longer if caffeine hits you hard.
Are sugar-free energy drinks better for sleep?
Not for caffeine. Sugar-free versions usually have the same caffeine as the originals, for example 80 mg in both Red Bull and Red Bull Sugarfree 8.4 oz, so the bedtime cutoff is the same.
Sources
- Gardiner C, et al. The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Med Rev, 2023.
- Gardiner CL, et al. Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial. Sleep, 2025.
- Kaldenbach S, et al. Energy drink consumption and sleep parameters in college and university students: a national cross-sectional study. BMJ Open, 2024.
- Drake C, et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med, 2013.
- EFSA. Caffeine (single doses and sleep).
- Red Bull. How much caffeine is in a can of Red Bull Energy Drink?
General wellness information, not medical advice. If you're pregnant, have a heart condition, or take medication that affects caffeine, check your limits with a doctor.