Doctor's Best, Science Based Nutrition, featuring the most trusted and purest pharmaceutical-grade L-tryptophan in the world, Ajinomoto TrytoPure, to help promote healthy mood function and normalize sleep..

Best L-Tryptophan (500 mg) featuring TryptoPure 90 caps

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Best L-Tryptophan (500 mg) featuring TryptoPure™

90 Vegetable Caps

Best L-Tryptophan contains TryptoPure™ which is produced by Ajinomoto the world's leading maker of amino acids. TryptoPure™ is considered the purest, most trusted L-tryptophan available. Manufactured via fermentation strictly from vegetable sources, it is between 99% and 100% pure. The level of impurities in tryptophan from other makers may be much higher.

Tryptophan is an essential amino acid readily converted by the body to the neurotransmitter serotonin. Able to cross the blood-brain barrier, L-tryptophan is altered by enzymes to first form the intermediate amino acid 5-HTP and then serotonin. It is also the metabolic precursor to melatonin and to the B vitamin niacin. Supplementing the diet with pure L-tryptophan like TryptoPure™, found in Doctor’s Best L-Tryptophan products, can improve sleep and enhance mood, and may also be beneficial in reducing carbohydrate cravings. 


  • Promotes Normal, Healthy Restful Sleep*
  • Enhances Mood and Sensations of Well-being*
  • Decreased Carbohydrate Cravings to Support Weight Management Efforts
Supplement Facts
Serving Size: 1 capsule
Ajinomoto L-tryptophan 500 mg

† Daily Value (D.V.) not Established

Other Ingredients: Modified cellulose (vegetarian capsule) Suitable for vegetarians.

Does Not Contain: milk, egg, wheat, corn, sugar, sweeteners, starch, salt, or preservatives.

Contains nothing other than listed ingredients.

Suggested Use: Take 1 or 2 capsules daily, or as directed by a health practitioner. For optimum absorption, take separately from protein-containing foods and dietary supplements containing protein or amino acids.

MORE INFORMATION from Doctor’s Best

Adequate sleep is a necessity for maintaining proper health. Sleeping well enhances our ability to function during the day. The body requires sleep as downtime to regenerate and repair essential bodily functions and allow us to feel refreshed. L-Tryptophan is a potent nutrient that has been found to enhance restful, peaceful sleep via a number of mechanisms. L-tryptophan is best known for its ability to decrease the amount of time it takes to fall asleep (George et al. 1989; Hartmann 1982). It has also been shown in studies to enhance total sleep time, decrease intermittent wakening, and decrease early morning wakefulness (Schneider-Helmert 1981; Wyatt et al. 1970), allowing the body to feel rejuvenated.

The clinical efficacy of L-tryptophan is due to its ability to support normal production of serotonin in the brain (Demisch et al. 1987b; Hartmann 1982) (Demisch et al. 1987a). Serotonin has been implicated in the regulation of sleep, mood, appetite, and temperature, among other roles that it plays in the body (Birdsall 1998). In a review article summarizing findings from over fifty studies conducted between 1970 and 1985, researchers concluded that L-tryptophan enhances overall sleep quality and also effectively provides a remedy for occasional sleeplessness. * It does this without dangerous side effects and without any feelings of next-day drowsiness. (Leiberman 1985)(Schneider-helmert 1986).

Clinical studies show that L-tryptophan supplementation can positively affect mood and emotional well-being. A randomized, double blind, placebo-controlled trial of 115 individuals found that the administration of L-tryptophan was significantly more effective than placebo for enhancing mood and affect (Thomson J et al. 1982). The subjects took 1 gram of L-tryptophan or an identical placebo capsule three times per day for 12 weeks. Mood and affect were assessed using a standardized, clinically recognized rating scale. Scores in the group supplementing with L-tryptophan were significantly better than placebo at the end of the trial period, indicating L-tryptophan’s success at supporting healthy mood.

Further studies suggest that in healthy individuals, L-tryptophan has positive effects on mood, behavior, and emotional processing. For example, in a recent study of healthy females with normal moods and no history of depression, L-tryptophan supplementation alters the processing and perception of emotional stimuli towards a more positive bias. Supplementation with one gram three times per day caused an increase in happy facial expressions, a decrease in negative and disgusted facial expressions, and a decrease in the attention paid to negative words (Murphy et al. 2006). A second study conducted in 2006 with a double blind crossover design indicated that the same dose of L-tryptophan (1 gram three times per day) significantly decreased quarrelsome and aggressive behaviors while enhancing agreeable behaviors in everyday social interactions. In this study, participants reported more positive and less negative emotions and rated their interactions as more pleasant (aan het Rot et al. 2006).

A number of other studies point to the ability of L-tryptophan supplementation to balance mood. A study published in 1990 suggested that individuals with seasonal variations in mood responded well to supplementation with L-tryptophan (McGrath et al. 1990). Furthermore, compared to standard light therapy, the mood enhancement associated with L-tryptophan supplementation lasts longer after discontinuation than the effects seen after stopping light therapy (Ghadirian et al. 1998).

An additional double blind placebo-controlled study found that two grams of L-tryptophan administered three times a day, from the day of ovulation to the third day of menstruation (the luteal phase) in healthy women, significantly relieved the most prominent mood symptoms associated with PMS. After three months of use, women taking L-tryptophan experienced statistically significant control of extreme mood swings, sadness, irritability, and tension. It also improved their perceived quality of life (Steinberg et al. 1999).

L-tryptophan may play a supportive role in helping individuals who are currently involved in weight management programs and diets by helping to reduce carbohydrate cravings. During dieting, serotonin levels drop dramatically. Serotonin plays a role in controlling appetite, and eating carbohydrate-rich foods increases serotonin levels in the brain. This may explain carbohydrate cravings and resultant binge eating in some dieters. While no human trials have examined L-tryptophan supplementation directly, a number of clinical trials have used supplemental 5-HTP, the amino acid produced in the body from L-tryptophan. Results of these trials have shown decreases in overall food intake and a subsequent reduction in weight in individuals taking 5-HTP. (Birdsall, 1998). The majority (75%) of the decreased food intake was from carbohydrates, suggesting decreased cravings for carbohydrates in individuals on 5-HTP (Cangiano et al. 1991). It is likely that L-tryptophan supplementation would have similar effects.

Uncontaminated L-tryptophan has a thirty-year history of safety and absence of adverse effects at levels commonly consumed by humans. When administered in abnormally high dosages of 7 grams (for a 150 pound human) per day, potential side effects include gastric irritation, vomiting, and head twitching (2006). Use during pregnancy or lactation has not been studied as of yet and is, therefore, not recommended. L-tryptophan should not be used by individuals taking antidepressant drugs without close medical supervision.

By Jackie Griffith - Flag 
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Updated Oct. 27, 2016, about 4 years ago

SKU: DRB-00126
UPC: 753950001268
Distributed or manufactured from Doctor's Best. See more Doctor's Best products.

*Not intended to diagnose or treat diseases or ailments, and is not reviewed by the FDA.

Uses & Indications.
  • Enhancing Mood
  • Supporting Restful Sleep
Ailments & Concerns.
  • Mood Swings
  • Anxiety
  • Sleeplessness
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