Zoa vs Monster Energy: caffeine compared
Zoa and Monster Energy carry the same caffeine per serving: 160 mg each. Per fluid ounce, Zoa is the stronger drink: 13.3 mg/oz versus 10.0 mg/oz.
| Zoa | Monster Energy | |
|---|---|---|
| Serving | 12 oz | 16 oz |
| Caffeine per serving | 160 mg | 160 mg |
| Per fl oz | 13.3 mg | 10.0 mg |
| Share of 400 mg/day | 40% | 40% |
| Servings to reach 400 mg | 2.5 | 2.5 |
| Hours until under 50 mg | 8.4 h | 8.4 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 2:37 PM | 2:37 PM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 9:37 AM | 9:37 AM |
| Share of the 200 mg pregnancy limit | 80% | 80% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Zoa or Monster Energy?
Neither: both have about 160 mg per serving.
Which is stronger per ounce, Zoa or Monster Energy?
Zoa: about 13.3 mg per fl oz versus 10.0 mg for Monster Energy. Serving size decides the total you actually drink.
When should I stop drinking Zoa or Monster Energy before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Zoa by 2:37 PM, last Monster Energy by 2:37 PM. Half-life varies from about 1.5 to 9.5 hours between people.
Method
Caffeine per labeled serving, from the same drink table every calculator here uses (FDA/USDA reference amounts and manufacturer labels; see caffeine content of every drink). Brewed drinks vary batch to batch, so read these as typical values. Decay uses a 5-hour average half-life with a 45-minute absorption ramp; cutoff = bedtime − 5 h × log₂(dose ÷ limit). Percentages use the FDA's 400 mg/day figure for healthy adults and the 200 mg/day limit ACOG gives for pregnancy.
Source — Zoa: ZOA Energy can label, 12 fl oz (via GNC), checked 2026-10-13. 160 mg per 12 fl oz can; the serving was corrected from 16 oz to 12 oz.
Source — Monster Energy: CSPI caffeine chart (Monster Energy Original, 16 oz), checked 2026-10-13.