How Much Caffeine Is in C4 Energy? Performance, Ultimate and Smart Energy Cans

How much caffeine is in C4 Energy? A 16 oz can of C4 Performance Energy has 200 mg of caffeine, C4 Ultimate Energy has 300 mg per 16 oz, and C4 Smart Energy has 200 mg per 12 oz, according to Cellucor, the brand that makes C4. A standard C4 can is about two 8 oz cups of brewed coffee, and an Ultimate is about three.

At an average 5-hour half-life, 200 mg takes 15 hours to fall below 25 mg, and 300 mg takes almost 18. So a C4 is really a morning drink if sleep matters to you. The caffeine calculator works out your own cutoff for any can and bedtime.

How much caffeine is in each C4 energy drink?

Cellucor lists 200 mg for C4 Performance Energy, 300 mg for C4 Ultimate and 200 mg for C4 Smart Energy. These figures come from the product pages on cellucor.com, checked in November 2026.

C4 Smart Energy is the one to watch. It comes in a smaller 12 oz can but has the same 200 mg as the 16 oz Performance can, with caffeine from green coffee beans.

Is there a 500 ml C4 Energy, and how much caffeine does it have?

Cellucor's US site doesn't list a 500 ml C4 can, so we can't give an official figure for it. C4 is sold in 500 ml cans in some countries, and recipes outside the US can differ, so check the caffeine line printed on the can you're holding. Retailer listings aren't a reliable source here, because they don't always agree.

If your can says its caffeine per can, plug that number into the caffeine calculator as a custom drink and it will give you the same bedtime math as the tables below.

Is C4 Energy stronger than coffee, Red Bull or Monster?

Yes. A 16 oz C4 Performance Energy (200 mg) has about twice the caffeine of an 8 oz cup of coffee, and more than a 16 oz Red Bull (151 mg) or Monster (160 mg). C4 Ultimate, at 300 mg, has about twice what a 16 oz Red Bull does.

For the two biggest brands side by side, see Monster vs Red Bull caffeine.

How much C4 caffeine is left at bedtime?

A 200 mg C4 at 2 PM still leaves about 57 mg in you at 11 PM, and a C4 Ultimate leaves about 86 mg. The table uses the calculator's math: remaining caffeine = dose x 0.5^(hours / 5), for an 11 PM bedtime.

This site uses about 25 mg at bedtime as a sensible ceiling. It isn't an official limit, just a useful line. A 6 PM Ultimate leaves about as much caffeine at bedtime as a fresh 16 oz Red Bull.

What's the latest time to drink a C4 Energy?

For an 11 PM bedtime, finish a 200 mg C4 by about 8:00 AM. A 300 mg C4 Ultimate would need to be finished by about 5:05 AM. These are the times each can falls below 25 mg by bed:

In hours before bed, that's 15 hours for a 200 mg can and about 17 hours 55 minutes for Ultimate. C4 is sold as a performance drink, and a can before an evening workout is about the hardest timing for sleep. If you train after work, see pre-workout before bed and how long pre-workout lasts.

In an at-home sleep study, a large caffeine dose taken 6 hours before bed cut total sleep by more than an hour. For more on the bigger picture, see energy drinks and sleep.

How many C4 energy drinks a day is safe?

For healthy adults, the FDA cites 400 mg of caffeine a day as an amount not generally linked to negative effects. That's two 200 mg C4 cans and nothing else, or one C4 Ultimate plus one cup of coffee.

Cellucor's own warning on C4 Performance Energy says not to drink it if you are pregnant or nursing, that it is not intended for children, and that it is recommended for adults. The FDA notes that medical experts advise against energy drinks for children and teens. If you have a heart condition or take medications, talk to your health care provider about a lower limit. For a full daily tally, see how much caffeine is too much.