Product Image

L-Tryptophan 500 mg

Jarrow Formulas
4.4
★ ★ ★ ★ ★
(1483 ratings)
Tryptophan 500 mg
Product Image
Score83
500 mg of L-tryptophan offers a focused serotonin-precursor approach with strong value, though the formula covers only one pathway.
How scoring works
Quantity:60 Veggie Cap(s) • (60 servings)
Goals:
Sleep Support
Mood Support
Stress Relief

Score 83

500 mg of L-tryptophan offers a focused serotonin-precursor approach with strong value, though the formula covers only one pathway.
How scoring works
$12.70($0.21 per serving)
Vitacost
$ 19.12
iHerb
$ 14.96
Daily Vita
$ 18.99
Amazon
$ 19.12
Pure Formulas
$ 19.12
Daily Vita
$ 12.70
Report prices

Analysis

L-tryptophan supplies a precursor used in serotonin and melatonin production. The 500 mg amount is a practical starting serving in a vegetable capsule.

The generic source does not disclose purity grade or fermentation details. Effects can vary with timing, diet, and individual metabolism.

No competing amino acids are listed, which supports focused timing away from protein-heavy meals. The formula is focused on one neurotransmitter pathway and does not provide broad sleep, stress, or mood coverage.

Who is it for
  • Adults seeking targeted sleep or mood support
  • Users starting with a moderate tryptophan amount
Best for
  • Evening or mood-support routines
  • Standalone tryptophan supplementation

Pros

  • Provides 500 mg of L-tryptophan
  • Contains no competing amino acids
  • Vegetable capsule format
  • Strong value

Cons

  • Purity and fermentation details are not disclosed
  • Covers only one neurotransmitter pathway
  • Response may depend on meal timing and individual metabolism

Warnings

  • Do not combine L-tryptophan with SSRIs, SNRIs, MAO inhibitors, tramadol, triptans, or other serotonin-raising medicines without prescriber guidance.
  • Seek urgent care for agitation, confusion, heavy sweating, tremor, or a rapid heartbeat after a serotonergic combination because these can signal excessive serotonin.
  • L-tryptophan may cause drowsiness, so avoid driving or other alertness-dependent tasks until its effects are clear.

Nutrient quality

93 Highest impact

The standalone L-form avoids competing amino acids, but source-grade details are not supplied. The tryptophan amount is substantial for targeted supplementation.

Ingredient transparency

83 Highest impact

Every listed active has an individual amount and no proprietary blend hides key doses. Daily directions and the complete inactive-ingredient list are not supplied.

Customer satisfaction

65 High impact

The supplied average is mixed and the aggregate pool is substantial. No specific feedback is provided to assess recurring complaints or whether experience matches the intended use.

Value for money

86 Highest impact

Serving cost is moderate for the disclosed active amount. The focused design avoids paying for unnecessary active ingredients.

Report analysis

Goals

Sleep Support
Impact
Highest effect
B+ Goal FitA Strength of SupportC+ CoverageA Formula Quality

L-tryptophan supports the body's serotonin and melatonin production pathway and is reasonably aligned with sleep onset. Its effect is less direct than melatonin and it does not provide a separate relaxation pathway.

The amount is clearly disclosed and falls within a useful range, while the standalone capsule avoids competing amino acids. People using serotonin-raising medicines should avoid combining them without clinical guidance because tryptophan may increase serotonergic effects.

Study evidence
Tryptophan Mixed 1 study
Mood Support
Impact
Highest effect
B Goal FitA+ Strength of SupportD+ CoverageA Formula Quality

The standalone L-tryptophan dose fits a well-supported serving range and supplies a serotonin building block. Taking it without competing amino acids supports absorption, while missing purity and sourcing details leave some quality uncertainty.

The formula offers meaningful depth for one neurotransmitter pathway but little broader stress or neuroprotective coverage. L-tryptophan may add to the effects of SSRIs, MAO inhibitors, and other serotonin-raising drugs, increasing the risk of excessive serotonin.

Study evidence
Tryptophan Mixed 1 study
Stress Relief
Impact
High effect
B- Goal FitB Strength of SupportC- CoverageA+ Formula Quality
Tryptophan · 500 mg

L-tryptophan supports serotonin production and may help when stress affects mood or the ability to settle at night. Its role is relevant but narrower and less direct than an adaptogen that targets the physiological stress response.

The 500 mg amount is a meaningful starting dose with full disclosure, although no enhanced-purity or source details are provided. Tryptophan can cause drowsiness and may add to serotonin-related effects when combined with SSRIs, SNRIs, MAOIs, or other serotonergic medicines.

Study evidence

Ingredients

IngredientAmount per serving
L-Tryptophan
500 mg
Gluten Free Adults 18–50 Vegan Dairy Free Vegetarian
Report overview
Tryptophan · 500 mg OverallScore84
B- Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

The standalone capsule supplies a clearly disclosed amount that fits the well-supported serving range and avoids competing amino acids. Source purity and fermentation details are not provided, which limits quality assurance. L-Tryptophan can add to the effects of SSRIs, MAO inhibitors, and other serotonin-raising drugs, creating a risk of excessive serotonin.

Loading alternative details
Report alternatives

Sources

Published studies used for the product analysis and the top-ranked studies for each ingredient and goal.

  1. A systematic review of the effect of L-tryptophan supplementation on mood and emotional functioning
    Kikuchi AM, Tanabe A, Iwahori Y · Journal of Dietary Supplements · 2021
    Systematic review11 studies pooledMood Support forTryptophan
  2. The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression
    Clarinda N Sutanto, Wen Wei Loh, Jung Eun Kim · Nutrition Reviews · 2022
    Meta-analysis4 studies pooledSleep Support forTryptophan