Dr. Grey AI

Tryptophan

L-tryptophan is an essential amino acid precursor to serotonin. 40 controlled studies show doses ≥1g reduce sleep latency. Effective for mild-moderate depression but not severe. Used successfully for seasonal affective disorder. Do not combine with SSRIs/MAOIs (serotonin syndrome risk). 1989 contamination incident (EMS outbreak) was traced to single manufacturer - supplement itself is safe.

Quick Answer

What it is

L-tryptophan is an essential amino acid precursor to serotonin. 40 controlled studies show doses ≥1g reduce sleep latency.

Key findings

  • Grade B: Sleep Latency (Sleep Quality)
  • Grade B: Subjective Sleepiness (Sleep Quality)
  • Grade C: Depression Symptoms (Mild-Moderate) (Depression)

Safety

  • Do not combine with SSRIs/MAOIs (serotonin syndrome risk).
ℹ️ Quick Facts: Tryptophan

Quick Facts: Tryptophan

  • Best Evidence:Grade B
  • Conditions Studied:3
  • Research Outcomes:6
  • Grade B Findings:2
  • Key Effect:Sleep Quality
Outcomes by grade:
A0
B2
C3
D1
3 conditions · 6 outcomes

Detailed Outcomes

|
B
Sleep Latency
Doses ≥1g decrease sleep latency; best results in mild insomnia
40 studies
moderate↓Improves
B
Subjective Sleepiness
Increased rated subjective sleepiness at doses ≥1g
20 studies
moderate↑Improves
C
Depression Symptoms (Mild-Moderate)
Better than placebo for mild-moderate depression (Cochrane review)
10 studies
moderate↓Improves
D
Severe Depression
Not effective for severe depressive symptoms
5 studies
small↓Improves
C
Memory
Memory improvements mainly in populations with serotonergic disturbances
8 studies
small↑Improves
C
SAD Symptoms
As effective as light therapy for seasonal affective disorder
3 studies
moderate↓Improves

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