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ING-078Ingredient Research Profile

Sleep & Recovery

L-Tryptophan

●●○Moderate Evidence

The dietary amino acid precursor to serotonin and melatonin. More natural than 5-HTP but less potent — larger doses needed. High-carb meals enhance tryptophan brain uptake.

Effective Dose

500–2000mg / day

per clinical evidence

Evidence Level

Moderate

Sleep & Recovery

Mechanism

Serotonin and melatonin biosynthesis precursor

primary action

Best For

Sleep onset

Mood, Appetite control

This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.

What Is L-Tryptophan?

Tryptophan is an essential amino acid found in turkey, dairy, eggs, and seeds. It is the starting point for serotonin synthesis (tryptophan → 5-HTP → serotonin → melatonin). Unlike 5-HTP, tryptophan must first pass the rate-limited tryptophan hydroxylase step and competes with other large neutral amino acids for blood-brain barrier transport.

How It Works: The Science

Tryptophan is hydroxylated to 5-HTP by tryptophan hydroxylase (TPH) in the raphe nuclei. Insulin release from carbohydrate meals reduces competing LNAA blood levels, increasing the tryptophan:LNAA ratio and enhancing brain uptake. Tryptophan metabolism also feeds into the kynurenine pathway — relevant for immune function and NAD+ production.

Primary Mechanism

Serotonin and melatonin biosynthesis precursor

Evidence-Based Benefits

Reduces sleep onset latency

moderate

Hartmann & Elion (1977) — 1g tryptophan reduced sleep latency in healthy adults

Improves mood and reduces aggressive behaviour

moderate

Roiser et al. (2006) — tryptophan supplementation reduced negative affect in healthy volunteers

Dosage Guide

Effective Dose

500–2000mg / day

500–2000mg, taken 30–60 minutes before bed on an empty stomach or with carbohydrates only (not protein — other amino acids compete for transport). Less potent than 5-HTP but safer long-term for continuous use.

Safety Profile & Side Effects

Generally safe. Avoid with SSRIs, MAOIs, and serotonergic drugs (serotonin syndrome risk, same as 5-HTP). High doses may cause nausea.

Who Should (and Shouldn't) Take It

Best for
Sleep onsetMoodAppetite control
Who it's for

Those preferring a natural amino acid over the more potent 5-HTP. Good starting point for sleep and mood supplementation. Works best alongside a carbohydrate-containing evening snack.

Frequently Asked Questions

What is the recommended dose of L-Tryptophan?

500–2000mg, taken 30–60 minutes before bed on an empty stomach or with carbohydrates only (not protein — other amino acids compete for transport). Less potent than 5-HTP but safer long-term for continuous use.

Is L-Tryptophan safe?

Generally safe. Avoid with SSRIs, MAOIs, and serotonergic drugs (serotonin syndrome risk, same as 5-HTP). High doses may cause nausea.

How does L-Tryptophan work?

Tryptophan is hydroxylated to 5-HTP by tryptophan hydroxylase (TPH) in the raphe nuclei. Insulin release from carbohydrate meals reduces competing LNAA blood levels, increasing the tryptophan:LNAA ratio and enhancing brain uptake. Tryptophan metabolism also feeds into the kynurenine pathway — relevant for immune function and NAD+ production.

Who should take L-Tryptophan?

Those preferring a natural amino acid over the more potent 5-HTP. Good starting point for sleep and mood supplementation. Works best alongside a carbohydrate-containing evening snack.

Related Ingredients

5-HTP (5-Hydroxytryptophan)MelatoninMagnesium (Glycinate / Malate)Glycine

Medical Disclaimer

Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →