L-Tryptophan is a mood and sleep support supplement that helps you feel more balanced, calmer and rested throughout the day. Each capsule holds 500 mg of L-Tryptophan, the essential amino acid that supports serotonin synthesis. Swanson's commitment to quality means making to good manufacturing practice standards and careful quality checks. This heritage of quality helps you feel confident in daily wellbeing.

Available Sizes & Variants:

60 capsules - Standard monthly supply for steady mood support.

Benefits & Features:

• Helps mood and sleep balance.
• Delivers 500 mg of L-Tryptophan per capsule, a potent precursor to serotonin.
• Pure single-ingredient formula aligns with good manufacturing practice standards and strict quality checks.
• Evenings are when many people prefer tryptophan, as the body converts it into serotonin and melatonin, promoting calmer evenings and easier winding down for sleep.
• Pairs well with a vitamin D supplement as part of a balanced wellness routine.

Swanson's L-Tryptophan is produced in FDA inspected, good manufacturing practice certified facilities in the United States, with third party testing ensuring purity and potency. The product uses pharmaceutical grade L-Tryptophan, underscoring Swanson's long history in science backed wellness. Each batch reflects careful sourcing and strict quality assurance, a hallmark of the Swanson brand developed over decades. For customers exploring a holistic routine, this product sits alongside other trusted options like n acetylcysteine and a vitamin d supplement to support overall wellbeing.

(other) Gelatin, rice flour, magnesium stearate.

• GTIN: 87614115023
• Manufacturer: Swanson
• Categories: New ArrivalsSwansonTryptophan Supplements
• Best buy: 6 - 24 months+

United Kingdom Shipping:

Orders placed by 2pm (Monday to Friday) are dispatched the same day. Orders placed after 2pm will be dispatched the next working day.

Free shipping on orders over £50 to the UK.

Returns: Our products are meant to make you feel healthy and at your best. If you need to return your item, you can do so free of charge within 30 days in the same original and unopened packaging. Subject to T&C's.

To reap the benefits of this supplement, ingest one capsule with water 30–60 minutes prior to bedtime. As a food supplement\, take 1 capsule daily\, with a meal\, or as directed by your healthcare professional.

Please consult the product packaging for accurate instructions on how to use the product.

1. Promotes Healthy Sleep: L-Tryptophan is an essential amino acid that helps the body produce serotonin, a neurotransmitter that promotes relaxation and helps regulate sleep. By taking L-Tryptophan supplements, you may experience improved sleep quality and better overall rest.
2. Supports Mood and Emotional Wellbeing: L-Tryptophan is a precursor to serotonin, a neurotransmitter that plays a key role in regulating mood and emotions. By increasing your intake of L-Tryptophan, you may experience a more positive outlook and improved emotional wellbeing.

The Active Ingredient Is: L-Tryptophan

L-Tryptophan is an essential amino acid that helps with protein building and acts as a precursor to serotonin, a brain chemical tied to mood, sleep and cognitive function.

This form is the naturally occurring amino acid used in dietary supplements to supply tryptophan for body processes, and research has noted its part in serotonin synthesis and related functions.

What Does L-Tryptophan Do?

L-Tryptophan participates in brain serotonin synthesis, a process tied to mood regulation and sleep-related mechanisms. Research discussion also notes its potential role in supporting sleep quality through serotonin and melatonin pathways.

Dr. Richard at the University of Rochester Medical Center found that tryptophan's role in brain serotonin synthesis is an important factor in mood, behaviour and cognition.

This supplement is not intended to diagnose, treat, cure, or prevent any disease.

Welzo partners with brand partners who show a proven commitment to quality, safety and transparency. This is why Swanson was chosen as our supplier for L-Tryptophan. The brand is recognised for its strong manufacturing heritage and its dedication to really rigorous quality systems, with production in FDA-inspected, GMP-certified facilities that emphasise traceability, contamination prevention and robust quality assurance. This foundation underpins Swanson’s ability to deliver pure, potent ingredients that align with industry best practices.

Swanson’s product profile reflects a straightforward, science-informed approach to ingredient selection, prioritising pharmaceutical-grade L-tryptophan and careful dosage accuracy. This jives with Welzo’s emphasis on safe, well-supported supplementation and with our team’s evaluation criteria. Our trust is reinforced by Swanson’s established reputation and its alignment with our quality standards, including third‑party testing practices that support purity and potency. This brand’s strengths pair well with the product’s focus on clean, single-ingredient formulation.

This partnership was carefully and thoroughly evaluated by Welzo's healthcare professionals for compliance with our rigorous testing protocols, ensuring a trustworthy fit for our customers.