Melatonin and Glycine

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

Melatonin

A circadian signal, not a sedative — brilliant for jet lag and shift work at low doses, mediocre as a nightly sleeping pill.

Grade B2 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.

Compound or practice

Glycine

A cheap amino acid that lowers core temperature for easier sleep onset and supports collagen and glutathione.

Grade B2 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.

Swap the two

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 Melatonin

Jet lag / circadian shift Moderate effectEvidence grade B
Sleep onset (insomnia) Small effectEvidence grade B

Graded only in Glycine

Sleep onset / quality Small effectEvidence grade B
Next-day alertness Small effectEvidence grade C

Conditions

Only in Melatonin

Jet lag ImprovesEvidence grade B
Delayed sleep phase ImprovesEvidence grade B

Only in Glycine

None.

What each entry says about the other

Melatonin’s entry · Mind the timing: Both pre-bed and compatible.
Melatonin’s entry · Watch with: Both pre-bed and compatible.
Glycine’s entry · Mind the timing: Both pre-bed and compatible — glycine 60–90 min out, melatonin ~30.
Glycine’s entry · Watch with: Both pre-bed and compatible — glycine 60–90 min out, melatonin ~30.

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.