Caffeine and Melatonin: side effects, safety & interactions
Each entry’s own grades, side by side. A grade says how strong the evidence is for one outcome — it does not rank one entry over the other.
Compound or practice
Caffeine
The most-used and best-evidenced cognitive and physical stimulant on earth — precise dosing and a hard afternoon cutoff are the whole skill.
Grade A4 graded outcomesrevised Jul 10, 2026
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
Safety
Melatonin: side effects, safety & interactions
Safe short-term; grogginess and vivid dreams at high doses. It is a hormone, so caution in pregnancy and with autoimmune
Grade B0 graded outcomesrevised Jul 10, 2026
Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.
Graded in both
Outcomes are matched by name. Two entries can describe the same outcome in different words, so one listed further down may still be graded in the other.
No outcome has the same name in both entries. They may still overlap under different wording — read the two lists below.
Graded only in Caffeine
- Alertness / reaction time Moderate effectEvidence grade A
- Endurance performance Moderate effectEvidence grade A
- Strength / power Small effectEvidence grade B
- Sleep (afternoon dosing) Moderate effectEvidence grade A
Graded only in Melatonin: side effects, safety & interactions
None — every outcome it grades is graded in both.
What each entry says about the other
- Melatonin: side effects, safety & interactions’s entry · Watch with: Opposing signals — the afternoon caffeine cutoff protects the melatonin window.
Both columns are read from the entries as they stand in this library. A comparison is not advice to take either one, and it is no substitute for a clinician who knows the person.