What is Tryptophan?
Tryptophan is an essential amino acid as the body cannot synthesise it and needs to be obtained from the diet. Like all the essential amino acids tryptophan is needed for protein synthesis. This amino acid is a precursor to the neurotransmitter serotonin which then converts to the hormone melatonin that helps aid restful sleep. 5-Hydroxytryptophan (5-HTP), also known as oxitriptan is another amino acid created in the biosynthesis of tryptophan and is the precursor for serotonin.
There are three aromatic amino acids that absorb ultraviolet light which includes tryptophan, phenylalanine, and tyrosine. All three aromatic amino acids absorb ultraviolet light with tryptophan absorbing most of the UV light.
Very little research exists on amino acids and the efficacy of amino acid for therapeutic use as it cannot be patented and benefit enterprises or large companies in the same way as those involved with pharmaceuticals. With studies and research on amino acids and their potential uses limited by funding most studies include some findings in clinical settings.
Health Benefits of Tryptophan
Helps boost mood
Tryptophan is an essential precursor to the neurotransmitter serotonin which when sufficient helps boost mood and is known as the happy hormone. Serotonin is involved in regulating mood, sleep cycle, circadian rhythm, digestive system, happiness and wellbeing. A deficiency of tryptophan can lead to low mood.
Low levels of tryptophan has shown to cause an increase in anxiety levels and low mood which can lead to depression. [R] [R]
Many of the health benefits of tryptophan are dependent on the conversion to the neurotransmitter serotonin and its subsequent conversion to 5-HTP and melatonin.
Regulates Circadian Rhythm
The circadian rhythm is the body’s natural clock and works according to sunrise and sunset. Naturally our mind and body should be awake or awakening during sunrise and feeling sleepy after the sun sets. It is also important to get natural sunlight as you awaken after sunrise as natural daylight helps to regulate the hormone serotonin (“feel good hormone”) which is essential for the production of melatonin. Low serotonin levels are common in those who suffer from depression, a condition which is linked to insomnia.
Since the invention of the light bulb and all artificial light the body’s circadian rhythm is following an unnatural pattern. It is important to avoid artificial light as much as possible however certain lights can be beneficial for health. As an example people who live in northern climates and experience little sunlight may find benefit using SAD lamps in the day time which help mimic the sun’s natural light and may increase vitamin D production.
Helps aid in sleep
Tryptophan can also be used as a sleep aid. This essential amino acid has many health benefits in the body. It is able to convert to vitamin B3 which also helps with sleep.
Insomnia due to disruptions to the circadian rhythm can be helped by melatonin, an essential hormone that helps regulate sleep. Although supplements can be taken it is better to allow the body to produce this naturally as not much is known in terms of health risks associated with supplemental intake of melatonin.
Melatonin is a natural hormone the body produces from tryptophan after conversion of serotonin to 5-htp and you can enhance this by changing your sleep environment such as blocking out as much light as possible. It is recommended that your bedroom uses blackout curtains or blinds so the room is darker. Your bedroom should also be pitch black. You can keep your door closed to block out light from the hallway if this is left on.
Melatonin has been shown to improve sleep [R] [R]
Cereal fortified with tryptophan have shown to help with falling asleep and aid in restful sleep. [R]
Your sleep environment can directly impact the quality of your sleep. Very minor tweaks can be made to improve your sleep.
Avoid technology as much as possible. Artificial lights from phones, tablets etc will interfere with the body's ability to naturally produce melatonin. Even waking up and being exposed to artificial light for a minute can interfere with melatonin production. It may be helpful to wear sunglasses to avoid hallway lighting when needing to go to the toilet to empty bladder at night. Another option is to wear blindfolds for a better night sleep. Sometimes blindfolds can feel uncomfortable and instead using a piece of cloth or comfortable fabric over the eyes may help.
5HTP can help with sleep and has shown to increase vivid dreams. 5HTP is usually produced in the body from the amino acid tryptophan, so if you are already taking tryptophan for sleep or dream clarity avoid taking 5HTP. 5HTP pauses the initial REM periods of sleep giving deep sleep in usually the first few cycles. In the last few cycles a REM rebound occurs which makes up for the REM periods – this creates highly vivid REM sleep in the latter part of sleep which can enhance recall.
L-tryptophan has also been used for sleep apnea but more research is needed to determine its effectiveness and safety for this use. Studies have suggested that L-tryptophan supplementation may improve sleep quality and reduce the severity of sleep apnea symptoms in some individuals, but more research is needed to confirm these findings and to establish the optimal dosage and duration of treatment. It is important to consult with a healthcare professional before taking L-tryptophan or any other supplement for the treatment of sleep apnea.
If tryptophan does not help aid in sleep it may be due to lack of cofactors. Inositol may help instead, which is a B vitamin and may help aid in sleep. See agonists for more information.
Plays a part in behaviour
Tryptophan supplementation has been shown to influence good social behaviour. [R]
One study has shown that depleting tryptophan levels is directing linked to aggressive behaviour and impulsiveness. [R]
A low level of tryptophan is linked to attention deficit-hyperactivity disorder (ADHD), Tourette's syndrome and autism.
Helps reduce facial pain
There is some evidence showing that tryptophan may help with facial pain with one study showing a major positive impact on chronic maxillofacial pain [R]
A deficiency of tryptophan can reduce pain tolerance and increase pain sensitivity.
May help with menstrual disorder
Some menstrual disorders such as premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) are linked to an imbalance of the neurotransmitter serotonin which requires tryptophan for its production. One study has shown that increasing serotonin through tryptophan supplementation during the luteal phase can help women suffering from PMDD. 6 grams per day of tryptophan reduced mood swings, tension and irritability symptoms of PMDD. [R]
Women need more serotonin than men.
Helps reduce withdrawal symptoms of smoking cessation
Tryptophan has shown reduce withdrawal symptoms for smoking cessation along with a high carbohydrate diet. [R]
Tryptophan converts to niacin for many health functions
Niacin and niacinamide can be synthesized from the amino acid tryptophan in the liver however this production is not enough especially in the case of a deficiency.
Your nervous system and brain need niacin to function. Niacin can help maintain and strengthen the nervous system. Central nervous system neural degeneration has been linked to niacin deficiency.
Niacin significantly reduce anxiety and depression aiding good sleep and induce relaxation naturally. It has also been shown that those who suffer from schizophrenia and experience other psychiatric symptoms have a niacin deficiency which indicates that taking niacin supplements may help reduce these psychiatric conditions. Both forms of Vitamin B3, Niacin and Niacinamide can be used in treating physical and emotional stress. Vitamin B3 as niacin or niacinamide may be used for relieving symptoms associated with depression and anxiety. It is recommended by doctors to take either forms of Vitamin B3 in combination with Vitamin B1, B2 and C for vitamin B3 to be effective.
Niacin is also beneficial for improving memory of those with Alzheimer’s in combination with other B vitamins that help with memory functions.
Helps with neurotransmitter synthesis
Tryptophan is needed to convert to serotonin which is a neurotransmitter with various functions within the body. Serotonin is involved in mood, behaviour and general feelings of wellbeing and happiness. Serotonin is also needed to help synthesise melatonin, an important hormone produced in sleep during darkness and acts as a powerful antioxidant.
Agonist / Synergist
Minerals Mg, Ca, Zn
Vitamins B6 riboflavin (B2), niacin (B3), vitamin B6, zinc, B5, C
Other Carbohydrates, insulin
Magnesium and vitamin B6 is needed to convert tryptophan to serotonin
Tryptophan is needed for the synthesis of serotonin and melatonin
Tryptophan also supports production of GABA an important inhibitory neurotransmitter which requires serotonin and melatonin for its synthesis
Vitamin B2 is needed by the body to convert vitamin B6 and folate into forms it can use.
Vitamin B2 can help in the absorption of vitamins such as B1, B3, and B6 as well as minerals such as iron, zinc and folic acid. Most of the B vitamins also work well together and are needed by the body.
Tryptophan can be converted to vitamin B3 (niacin and niacinamide)
Niacin synthesis in the body also needs vitamins and minerals including iron, riboflavin, Vitamin B6 (PLP), also need trp and adequate energy.
Vitamin B6 can cause a host of health issues related to mood disorders such as depression and mood swings as it is involved in converting tryptophan into the mood regulating hormone serotonin.
Vitamin B6 plays an important role in aiding sleep by helping to convert tryptophan into serotonin and then into melatonin.
Calcium can help induce sleep as it aids the brain in utilizing tryptophan, an essential amino acid that helps the body’s ability to naturally manufacture melatonin. Dairy products such as cheddar cheese are abundant in both tryptophan and calcium which help aid in sleep.
If Tryptophan doesn't work and the person has difficulty falling asleep inositol may work instead. A dose of 650mg of inositol taken 1 hour before bedtime is recommended (for a person weighing 160 lb) to help aid sleep.
Other amino acids compete with tryptophan and in order to cross the brain blood barrier it helps to take some form of simple carbohydrate such as a teaspoon of honey.
Tryptophan requires vitamin B3, vitamin B9, iron and calcium to convert to 5-htp.
The conversion of 5-htp to serotonin requires zinc, vitamin B6 and vitamin C.
Vitamin B6 is an important co-factor and helps with amino acid metabolism
Serotonin conversion to melatonin is assisted by B5 and maintaining natural circadian rhythm by avoiding artificial lighting after dark and especially once in bed.
Tryptophan can raise cortisol levels which can cause health problems if there is an existing adrenal fatigue or poor adrenal health and this will need increased levels of vitamin B5 and vitamin C.
Release of insulin helps tryptophan to cross the blood brain barrier
Tryptamine is an indolamine metabolite of the essential amino acid tryptophan. Tryptamine is synthesised in the human gut by symbiotic bacteria. The bacteria help convert dietary tryptophan to tryptamine.
Tryptamine is a naturally occurring compound that can activate 5-HT4 receptors, which are involved in the regulation of gastrointestinal motility. Tryptamine can act as a hallucinogen and has been reported to cause feelings of euphoria.
An abundance of tryptophan can cause an increase in the metabolism of tryptamine. Tryptamine is metabolized by the Monoamine oxidases A and B (MAOs).
Nutmeg spice can increase tryptophan uptake especially when added to milk which contains the amino acid.
Antagonists
Tryptophan is depleted by pesticide which includes roundup
Tryptophan antagonizes phenylalanine and tyrosine as it competes with these amino acids for entry to the brain
High amounts of leucine prevents conversion of tryptophan to niacin
All amino acids can prevent tryptophan uptake – usually this can be corrected by taking carbohydrates with tryptophan to help cross the blood brain barrier.
BCAAs (Branched chain amino acids which includes luecine, isoleucine and valine) compete with tryptophan which can impact levels of neurotransmitter serotonin and its synthesis. [R]
Lactose has shown to deplete tryptophan
One study showed that 31.5 gm of amino acids without tryptophan lowered plasma total and free tryptophan by 71-78 % which resulted in behavioral and/or brain metabolism change.
Food Sources of Tryptophan
Animal food sources of this amino acid include beef, chicken, turkey, goose, duck, fish such as salmon, cheese, eggs and milk.
Plant based food sources of tryptophan include nuts (peanuts), pumpkin seeds, sesame seeds, soy bean, soy products, alfalfa, baked beans, beet, broccoli, brussels sprouts, carrots, cauliflower, celery, spinach, sweet potato, turnip, watercress, endive, fennel chive and spinach.
The spice nutmeg can increase tryptophan uptake especially when added to milk. The antioxidant spice turmeric is also sometimes added to the milk.
Cheese contains the amino acid tryptophan and can increase dreams.
Turkey also helps aid sleep and increase dreams. It is the amino acid tryptophan found in turkey that can help with sleep. Eating turkey in the afternoon or for supper can help set the mood for better sleep in the evening. Tryptophan does not easily cross the blood brain barrier and is best utilized when taking at least a teaspoon to 1 tablespoon honey with the turkey.
Oats and bananas contain tryptophan that will help aid sleep.
Tart cherry juice or extract can help aid in sleep. Montmorency sour cherries (Prunus Cerasus) naturally contain melatonin which is known to aid with sleep. Tart cherry is available as a drink and also in supplemental extract form.
Milk is another source of relaxing nutrients that may help with sleep. You can add some barley malt extract syrup to boost its sleep inducing properties. Milk helps as it contains high amounts of calcium that can help with a good night’s sleep inducing a natural state of relaxation.
Rotate your diet to get the optimal benefits out of the food you eat, rotating helps ensure adequate needs of the body are met sufficiently.
Recommended Daily Allowance
Adults need around 5mg per kg of body weight per day from dietary intake for optimal functioning.
Children need more amino acids that adults as their body is still developing. The recommended daily amount for children over the age of three increases by 10% to 20% more than what is needed by adults. For infants the amount required increases by 150% more than what is needed by adults.
The requirements may change on individual basis and highly dependent on existing health.
Tryptophan Supplementation
High protein meals should be avoided when supplementing with tryptophan as all amino acids prevent tryptophan from crossing the blood brain barrier. Tryptophan can effectively cross blood brain barrier when taken on an empty stomach and with some carbohydrates such as fruit or fruit juice, or teaspoon honey. It is important to avoid hot beverages when taking tryptophan or any other amino acids.
If supplementing with Tryptophan with any adrenal issues it is important to take high dosed vitamin B5 and vitamin C to help support adrenal health as tryptophan increases cortisol.
5htp can be taken instead of tryptophan. The effects of 5htp are different from Tryptophan where 5htp may induce more sleepiness. It may be ideal to take tryptophan in the morning and 5thp before bedtime.
In some countries tryptophan requires a prescription.
Taking single amino acid supplements are not always recommended and may be harmful for those with damaged liver or kidneys.
Deficiency Symptoms of Tryptophan
Signs and symptoms of low tryptophan levels include:
- Pain intolerance (Increased sensitivity to pain)
- Acoustic startle (reflex from sound)
- Motor activity
- Aggression
- Anxiety
- Irritability
- Impaired memory and learning
- Low serotonin levels
- Insomnia
- Depression
- Obesity
Causes of deficiency include:
- Insufficient dietary intake
- Depleted tryptophan levels by pesticides (eg. roundup / glyphosate)
- Impaired gut health (healthy gut bacteria strains help produce serotonin from tryptophan in intestines)
- Low tryptophan intake
- Tryptophan - low in those with autism
- High intake of competing amino acids
- Lack of carbohydrates (helps to cross the blood brain barrier)
- High or excessive BCAA intake
Tryptophan converts to another amino acid 5-HTP and is a precursor for the neurotransmitter and hormone serotonin and melatonin. A deficiency can also lead to a deficiency of serotonin and melatonin which greatly impacts sleep.
Tryptophan is often found to be low in children with ADHD with supplementation showing no signs of improvement. Tryptophan is also found to be lower in people with autism. Low tryptophan may not be a cause for these conditions and instead likely to be a result of these conditions.
Study on ADHD and Tourette’s syndrome shows a link with low levels of tryptophan [R]
Study shows impaired memory and cognition with low tryptophan levels. Low tryptophan impairs long-term memory and memories that are connected to events and experiences [R] [R]
Tryptophan is important for cognition as it is needed to produce neurotransmitter serotonin which has a very important role in cognitive function, memory and learning as well as balancing mood. [R]
A high intake of leucine intereferes with tryptophan to niacin conversion which can cause symptoms of pellagra that is often due to a niacin deficiency.
Elevated blood levels of BCAA deplete tryptophan in the brain, which causes low serotonin.
All amino acids compete with tryptophan. In order to help tryptophan cross the blood brain barrier it is ideal to consume some carbohydrates such as a tablespoon of honey at the same time as consuming food rich in tryptophan or supplemental tryptophan. The honey or other simple carbohydrate will raise blood sugar levels which will then cause a release of insulin. The release of insulin drives away from the blood all amino acids into the liver except for tryptophan. This process allows tryptophan to cross the blood brain barrier.
Another way to enhance intake is by taking tryptophan away from meals and especially meals containing other amino acids.
Low tyrosine depression and low tryptophan depression
Phenylalanine or tyrosine and tryptophan are amino acids linked to and are involved in the synthesis of some very important neurotransmitters that affect mood which is why a deficiency in either one of these can lead to depression and other mood disorders.
Tryptophan / serotonin type of depression
Low mood can be linked to either low tryptophan or low tyrosine and in many cases even both. Each type has various clues that can help pinpoint to which is causing the low mood. In low moods linked to tryptophan there is also a low production of serotonin, a key neurotransmitter that helps balance mood. When tryptophan is very low there is a craving for sweets and foods high in carbohydrates. People with this type of craving will find they are wanting to eat simple carbs more of the time such as white bread, pasta, rice and other simple carbs. Sleep is also a major clue to low mood associated with low tryptophan as it is linked to insomnia which may be corrected with supplementation.
Tryptophan needs carbohydrates to be able to cross the blood brain barrier which explains the cravings for carbohydrates. Gut health is also important as most of the serotonin is produced in the gut. Foods high in pesticide aggravate gut health, impair digestion and reduce tryptophan levels. Women suffering from PMS or PMDD with mood swings and irritability during late luteal phase are likely to be low in serotonin and may notice a reduction of symptoms on taking oral supplementation of tryptophan.
Depression can be a balancing act between the two neurotransmitters serotonin which needs tryptophan and norepinephrine which needs tyrosine or phenylalanine. There needs to be a healthy balanced ratio of both neurotransmitters. In some cases taking high doses of tryptophan to increase serotonin can cause psychiatric and depressive symptoms to become worse when other neurotransmitters such as dopamine or norepinephrine may be deficient. If serotonin levels are low than tryptophan use may be very helpful and reduce associated symptoms of deficiency but if norepinephrine or dopamine is low these can be worse, in this case tyrosine or phenylalanine should help address symptoms associated with depression.
People with high fear levels (phobias, anxiety, etc.) are usually deficient in serotonin. The amino acid tryptophan is converted into niacin which is converted into serotonin.
Supplementation of tryptophan or niacin will increase serotonin production and lower fear levels. Prozac and other similar drugs increase serotonin by decreasing its degradation, enabling the users to live life with less fear. It's easy to do the same thing by increasing tryptophan in the diet or supplementing with more niacin which may be a safer option.
People who crave excess carbohydrate food may end up reaching for more simple sugars such as processed sugar are likely to be deficient in tryptophan. However although the sugar helps cross the blood brain barrier and stimulates the pleasure inducing feelings associated with dopamine release which will only work for a shorter duration needing to increase more sugar next time in order to get the same response. This excessive sugar intake may be counterproductive in the long term creating all kinds of health imbalance. Excess simple sugars are also converted to saturated fats which if out of balance with essential fatty acids adds to more health related problems.
The healthiest approach of replenishing tryptophan levels and serotonin synthesis is a healthy diet that also supports the gut health as healthy bacteria can help synthesise serotonin in the intestines.
A PET scan of the human brain showed that it can take 5 hours for tryptophan to convert to serotonin after ingestion of amino acid consumption. [R]
Toxicity Symptoms of Tryptophan
Tryptophan is an essential amino acid, however excessive amounts can cause a host of symptoms. The signs and symptoms of excess tryptophan include:
- Serotonin syndrome
- Headache
- Lightheadedness
- Drowsiness
- Dry mouth
- Visual blurring
- Muscle weakness
- Sexual problems
- Reduced fear*
In 1989, L-tryptophan supplements were linked to eosinophilia-myalgia syndrome (EMS), a deadly condition which had 37 deaths and more than 1500 reports who had become sick after ingestion. Subsequently L-tryptophan was banned and existing tryptophan supplements recalled by FDA. EMS condition is linked to exposure of L-5-hydroxytryptophan which is not made in the same way as L-tryptophan.
Excessive tryptophan symptoms will be similar to excessive serotonin and a condition known as serotonin syndrome which can be life threatening and requires urgent medical intervention.
If too much tryptophan is converted in serotonin and there with MAO deficiency this can lead to high levels of serotonin which can reduce fear to such a level so as to create aggressive behaviour.
An interesting study showed that there is a Dutch family which has a genetic defect which causes a deficiency of MAO-A (which degrades serotonin and norepinephrine). Norepinephrine increases anger, while serotonin suppresses fear. The men in this family had double the normal levels of norepinephrine and nine times the normal levels of serotonin. The high norepinephrine made them get angry easily and the high serotonin almost completely eliminated any feelings of fear. This combination resulted in high aggression and violent behavior. They get angry and have no fear of the consequences of attacking those who make them angry. [R] [R]
Tryptophan can keep you awake all night or cause insomnia if you are a heavy drinker. [R]
Excessive tryptophan symptoms will be similar to excessive serotonin and a condition known as serotonin syndrome which can be life threatening and requires urgent medical intervention.