To be under 50 mg of residual caffeine at an 11 PM bedtime, have your last caplet of NoDoz Maximum Strength (200 mg) by 1:00 PM (13:00). The math uses the median 5-hour caffeine half-life; individual half-lives range from about 2 to 12 hours.
NoDoz Maximum Strength Last-Call Times by Bedtime
Latest time to finish one caplet of NoDoz Maximum Strength (200 mg of caffeine) and still be under 50 mg of residual caffeine at bedtime, assuming the median 5-hour half-life. Your personal half-life may sit anywhere in the 2 to 12 hour range.
| Bedtime | Last call for NoDoz Maximum Strength | Residual at bedtime |
|---|---|---|
| 9:00 PM (21:00) | 11:00 AM (11:00) | ~50 mg |
| 10:00 PM (22:00) | 12:00 PM (12:00) | ~50 mg |
| 11:00 PM (23:00) | 1:00 PM (13:00) | ~50 mg |
| 12:00 AM (00:00, midnight) | 2:00 PM (14:00) | ~50 mg |
Clearance Time by Serving Size
How long each serving of NoDoz Maximum Strength needs before bed to drop under 50 mg:
| Serving | Caffeine | Time needed before bed |
|---|---|---|
| 1 caplet | 200 mg | 10 h |
Source: caffeine figures from DailyMed (FDA drug label), NoDoz Alertness Aid Maximum Strength, accessed 2026-06-11. Values can vary by batch, location, and preparation; check the label or the source for the latest figures.
How the Math Works
Caffeine leaves your body by exponential decay. With the median 5-hour half-life, the 200 mg in one caplet of NoDoz Maximum Strength falls to 100 mg after 5 hours and 50 mg after 10 hours. To get under 50 mg, the level where caffeine stops measurably delaying sleep for most people, it needs about 10 h of clearance time. Subtract that from your bedtime and you get the last-call times above, rounded down to the nearest 15 minutes.
The big caveat: the 5-hour figure is a median. Depending on CYP1A2 genetics, medications, smoking, and pregnancy, real half-lives run from about 2 to 12 hours. If caffeine reliably keeps you up, treat these times as too generous and move your personal cutoff earlier, or model your own curve in the caffeine half-life calculator.