Introduction

L-Tryptophan is an essential amino acid required for the production of serotonin and melatonin—key chemicals that regulate mood, sleep, appetite, and stress response. Because the body cannot synthesize tryptophan, it must be obtained through diet or supplementation.

What Is L-Tryptophan?

L-Tryptophan is an essential amino acid that serves as a precursor to serotonin, melatonin, and niacin (vitamin B3).

• Type: Essential amino acid
• Main role: Neurotransmitter and hormone production
• Storage: Not stored; used as needed

How L-Tryptophan Works in the Body

After absorption, L-Tryptophan is converted into serotonin in the brain, which can further convert into melatonin.

• Precursor to serotonin (mood regulation)
• Supports melatonin production (sleep–wake cycle)
• Contributes to niacin (vitamin B3) synthesis
• Supports appetite and stress regulation

Sources of L-Tryptophan

• Milk and dairy products
• Turkey and chicken
• Eggs
• Fish
• Nuts and seeds (pumpkin seeds, sesame seeds)
• Legumes and soy products

L-Tryptophan Deficiency

L-Tryptophan deficiency is uncommon but may occur with low protein intake or chronic stress.

Possible deficiency symptoms include:

• Low mood or depression
• Sleep disturbances or insomnia
• Irritability or anxiety
• Poor concentration
• Increased appetite or cravings

Dosage & How to Take L-Tryptophan

• Daily dietary intake: ~0.9–1.2 g/day
• Supplemental dose: 250–1000 mg/day
• For sleep support: Often taken in the evening

L-Tryptophan is best taken on an empty stomach or with a light carbohydrate source.

Forms of L-Tryptophan

• Free-form L-Tryptophan
• Capsules or tablets
• Protein-based sources

Benefits & Uses

• Supports healthy mood and emotional balance
• Improves sleep quality
• Supports stress management
• Helps regulate appetite
• Supports overall mental well-being

Safety, Side Effects & Precautions

• Generally safe at recommended doses
• Excess intake may cause drowsiness or nausea
• Avoid combining with antidepressants without medical advice
• Do not exceed recommended dosages

Special Populations

• People with insomnia: May support sleep quality
• Individuals with low mood: Supports serotonin balance
• Elderly: May help with sleep regulation
• People under chronic stress: Supports emotional stability

Frequently Asked Questions

What does L-Tryptophan do in the body?

L-Tryptophan supports serotonin and melatonin production, influencing mood and sleep.

Is L-Tryptophan good for sleep?

Yes. It helps increase melatonin production and improve sleep quality.

Can L-Tryptophan be taken daily?

Yes, within recommended limits for healthy individuals.

Is L-Tryptophan the same as 5-HTP?

No. L-Tryptophan is a dietary amino acid, while 5-HTP is a direct serotonin precursor.

Best time to take L-Tryptophan?

In the evening or before bedtime for sleep support.