40 Studies That Prove The Science Of Tryptophan For Sleep

Sleep is a valuable commodity. Poor sleep quality can make you irritable, less productive, anxious, groggy, and honestly not that much fun to be around. Over the past several decades tryptophan has been studied extensively, investigating the effects on sleep quality and sleep duration. Studies have found that tryptophan may be a powerful therapeutic sleep-inducing amino acid, providing you with longer, better quality sleep.

What Is Tryptophan

Tryptophan is one of twenty essential amino acids. Your body does not naturally produce tryptophan, hence its role as “essential.” You must obtain tryptophan through dietary sources or from supplements. Tryptophan serves many important purposes, especially those related to sleep.

Tryptophan is involved in the process of creating serotonin and melatonin. Serotonin is an inhibitory neurotransmitter that is involved in emotion and mood, balancing excessive excitatory neurotransmitter effects in your brain. Melatonin, often referred to as the sleep hormone, helps regulate sleep-wake cycle, syncing your circadian rhythm or internal clock. Tryptophan is also utilized by the liver, creating niacin (vitamin B3) which is needed for energy metabolism and DNA production.

Does Tryptophan Help Sleep

Studies have shown that higher levels of tryptophan in the diet are negatively associated with symptoms of depression and positively associated with sleep duration [R]. A population study found in the Journal Nutrients analyzed 29,687 adults in the U.S and found that the average daily intake of tryptophan was 826 mg [R]. Analysis of sleep parameters show that higher doses of tryptophan reduce wake frequency, while increasing stage 3 and REM sleep [R].

5-hydroxytryptophan [5-HTP]

Tryptophan acts as a precursor for melatonin synthesis. AAD – aromatic amino acid decarboxylase is responsible for the conversion of 5-hydroxytryptophan [5-HTP] into serotonin. Melatonin is formed from serotonin through a phase of reaction with the help of two enzymes, AANAT and HIOMT [R].

Researchers believe the role of 5-HTP on serotonin and melatonin production, may help treat depression by balancing mood as well as induce sleep by increasing melatonin production.

Serotonin & Melatonin Production

Melatonin plays a crucial role in regulating sleep. Melatonin levels naturally begin to rise in the evening, initiating sleep and decline in the morning, to help you wake up. a systematic review published in the Journal PLOS One, analyzed 19 different studies and found that melatonin reduced time to get to sleep by an average of 7 minutes and increased overall sleep duration [R].

Tryptophan Benefits

1. Sleep Quality

Studies have shown that tryptophan can increase REM sleep and improve sleep quality. Tryptophan also plays a role in sleep regulation. 5-HTP induces sleep by increasing melatonin, (the sleep hormone) which helping you achieve better cycle. 

Melatonin is a naturally produced hormone and powerful antioxidant, that induces sleep by working with your circadian rhythm. Think of Melatonin as your internal bed-time reminder. Although melatonin won’t put you to sleep like other sleep aids, melatonin signals your body, putting it into a deeper sense of relaxation for sleep preparedness.

2. May Help Depression

Several studies have shown a correlation between lower tryptophan levels and depressive mood state. Researchers believe the role of 5-HTP on serotonin and melatonin production, may help treat depression by balancing mood as well as induce sleep by increasing melatonin production. Low levels of 5-HTP in the brain may be one factor precipitating depression in some patients [R].

Tryptophan Dosage

According to clinical research tryptophan dosage varies widely between 0.5 – 5g. On average U.S. adults get 826mg with those consuming a high-protein diet closer to 2-3g per day. Supplements containing other natural sleep aids, may be seen with lower doses due to overall melatonin production. 

Tryptophan Side Effects

Tryptophan is an abundant amino acid found in dietary sources. Studies show there are no negative side effects of liver and kidney function when taken at higher doses. Occasional side effects such as headache, nausea, dizziness and upset stomach.

Tryptophan For Sleep: Takeaway

Studies have shown that tryptophan is proven to be an effective amino acid, in stimulating serotonin and melatonin production. 5-HTP can help improve sleep latency, sleep duration, sleep quality and improve sleep cycles to further enhance and optimize sleep. Dietary protein sources do contain tryptophan, however adding a sleep supplement that contains tryptophan could prove to be efficacious in reducing symptoms of anxiety, increasing relaxation, and optimize sleep patterns.

Looking for the best sleep supplement to help you get better quality sleep.

Swolverine’s ZMT® maximizes your body’s ability to stimulate muscle growth by promoting high-quality sleep and naturally boosting testosterone levels. ZMT® is made with clinically dosed sleep ingredients such as Melatonin, GABA, Theanine, Tryptophan, Valerian Root, Magnesium Glycinate, and powerful adaptogens like Ashwagandha, Zinc, Rhodiola Rosea, DIM, and Tongkat Ali. ZMT is the perfect nighttime elixir for restful recovery and sleep



Lieberman HR, Agarwal S, Fulgoni VL 3rd. Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes. J Nutr. 2016 Dec;146(12):2609S-2615S. doi: 10.3945/jn.115.226969. Epub 2016 Nov 9. PMID: 27934652.

Nicholson AN, Stone BM. L-tryptophan and sleep in healthy man. Electroencephalogr Clin Neurophysiol. 1979 Nov;47(5):539-45. doi: 10.1016/0013-4694(79)90255-4. PMID: 91481.

Naseem, Mehar, and Suhel Parvez. “Role of melatonin in traumatic brain injury and spinal cord injury.” TheScientificWorldJournal vol. 2014 (2014): 586270. doi:10.1155/2014/586270


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