L-Tryptophan vs Melatonin

Sleep vs Sleep · evidence-backed comparison

Quick take
  • Melatonin has the stronger evidence base (strong (multiple rcts / meta-analyses)).
  • Melatonin has the broader effect profile across the 9 effect categories.
  • Melatonin is cheaper per serving ($0.05 vs $0.35).

Side-by-side traits

TraitL-TryptophanMelatonin
Category
SleepSleep
Active compound
L-tryptophanN-acetyl-5-methoxytryptamine
Form available
Capsule, PowderCapsule, Tablet, Liquid, Gummy
Source
microbialsynthetic
Typical dose
500–1500 mg0.3–3 mg
Dose range
500–1500 mg0.3–3 mg
Loading protocol
Best taken with
carbs (improves CNS uptake), empty stomach30–60 min before bed
Best time of day
eveningevening
Bioavailability
How efficiently the body absorbs and utilizes the compound.
Moderate (3/5)Moderate (3/5)
Onset time
Acute: 60 minAcute: 30–60 min
Half-life
~2 hours20–50 min
Evidence level
Quality and quantity of human research.
Moderate (some RCTs)Strong (multiple RCTs / meta-analyses)
Overall effect
Subjective effect magnitude.
Moderate (3/5)Moderate (3/5)
Muscle / strength
Very Low (1/5)Very Low (1/5)
Physical energy
Very Low (1/5)Very Low (1/5)
Focus / cognition
Very Low (1/5)Very Low (1/5)
Mood / stress
High (4/5)Low (2/5)
Sleep quality
High (4/5)Very High (5/5)
Immunity
Very Low (1/5)Low (2/5)
Recovery
Post-exercise recovery support.
Very Low (1/5)Moderate (3/5)
Longevity / healthspan
Very Low (1/5)Moderate (3/5)
Safety rating
5 = exceptionally well-tolerated; 1 = significant risk profile.
High (4/5)High (4/5)
Price per serving
Approximate USD per typical daily dose.
$0.35$0.05
Vegan friendly
YesYes
Gluten free
YesYes
3rd-party tested
YesYes

About L-Tryptophan

Serotonin and melatonin precursor. Generally safer than 5-HTP for daily use, with strong sleep-onset and mood support.

Active compound: L-tryptophan
Forms: Capsule, Powder
Onset: Acute: 60 min
serotoninmoodsleep-onset

About Melatonin

Pineal-gland hormone that signals 'night-time' to the body. Most useful for jet lag and shifted sleep schedules; lower doses (0.3 mg) often work better than 5–10 mg.

Active compound: N-acetyl-5-methoxytryptamine
Forms: Capsule, Tablet, Liquid, Gummy
Onset: Acute: 30–60 min
sleep-onsetjet-lagcircadian

L-Tryptophan safety

Common side effects:

  • Drowsiness
  • GI upset
  • Dry mouth

Avoid if:

  • SSRI use (serotonin syndrome)
  • Liver disease

Drug interactions:

  • SSRIs
  • MAOIs
  • Sedatives

Melatonin safety

Common side effects:

  • Vivid dreams
  • Morning grogginess (high doses)
  • Headache

Avoid if:

  • Autoimmune disease
  • Pregnancy
  • Driving for hours after

Drug interactions:

  • Birth control
  • Anticoagulants
  • Antidepressants
  • Diabetes meds

Common uses

  • Sleep onset
  • Mood
  • Carb cravings

Stacks well with: Magnesium Glycinate

Common uses

  • Jet lag
  • Shift work
  • Sleep onset
  • Circadian rhythm

Stacks well with: Magnesium Glycinate, Glycine

Medical disclaimer

SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements — especially if you are pregnant, breastfeeding, take prescription medication, or have a chronic condition.