Triptophan: spelling variant of the essential amino acid L-tryptophan
Triptophan is a common spelling variant of the essential amino acid L-tryptophan. The correct form is tryptophan with the y, which carries the precise chemical name. The variant triptophan often arises through mispronunciation or typing error. Pharmacologically and biochemically the same substance is meant.
Tryptophan is one of nine essential amino acids and is taken in with food. Rich sources are meat, fish, dairy, eggs, legumes, nuts and chocolate. Clinically, tryptophan is mainly important as a precursor of serotonin and melatonin and for the synthesis of vitamin B3 (niacin) and NAD.
Mechanism of action
L-tryptophan is metabolised in the body via several pathways:
- Serotonin synthesis: tryptophan hydroxylase converts tryptophan to 5-hydroxytryptophan, which is then converted to serotonin. Serotonin regulates mood, sleep, appetite, pain perception and gastrointestinal function
- Melatonin synthesis: serotonin is converted in the pineal gland to melatonin, the sleep hormone
- Niacin synthesis (vitamin B3): via the kynurenine pathway part of the tryptophan is converted to NAD and NADP
- Protein biosynthesis: tryptophan is part of many proteins
Additional tryptophan intake via supplements increases availability for serotonin synthesis if uptake into the CNS succeeds against the competition of other large neutral amino acids. Carbohydrate-rich meals improve tryptophan uptake into the brain because insulin shifts the other amino acids into muscle cells.
Indications
- Sleep disturbances, especially difficulty falling asleep: as supportive therapy
- Depressive moods: off-label, especially as augmentation or in patients who do not want classic antidepressants
- Seasonal affective disorder (SAD): complementary to light therapy
- Premenstrual syndrome (PMS): off-label
- Pellagra: niacin deficiency with diarrhoea, dementia and dermatitis, can be treated with tryptophan and niacin
Tryptophan is available as a medicine (Kalma) and food supplement. With diagnosed psychiatric conditions, use should be embedded in the overall concept.
Dosing and administration
Sleep disturbances: 500 to 1,000 mg about 30 minutes before bed, combined with a carbohydrate-rich meal.
Depressive mood: 1,000 to 3,000 mg per day, divided into two to three doses.
Take between meals or with a carbohydrate-rich snack to promote CNS uptake. Do not take with protein-rich food, since other large amino acids compete for the same brain transporter.
Treatment duration: for sleep disturbances, short term or as needed; for chronic complaints, the diagnosis and overall concept should be reassessed.
Side effects
Common: nausea, abdominal pain, heartburn, constipation, fatigue, dry mouth.
Uncommon: headache, dizziness, slightly raised liver values, rash.
Rare: eosinophilia myalgia syndrome (EMS) with contaminated tryptophan products in the 1990s, which led to a temporary withdrawal; current preparations from controlled sources are considered safe.
Special notes:
- In eosinophilia myalgia syndrome (1989) impurities were the main trigger, not the amino acid itself
- Combination with serotonergic drugs carries a risk of serotonin syndrome
- With prolonged high-dose use, possible interference with vitamin B3 metabolism
Interactions
- MAO inhibitors (tranylcypromine, moclobemide): risk of serotonin syndrome, combination contraindicated
- SSRIs, SNRIs, triptans, lithium, tramadol, pethidine: additive serotonergic effect, risk of serotonin syndrome; combination possible but counsel about warning signs
- Sedatives and hypnotics: additive sedation
- Anticonvulsants: theoretical level changes, rarely clinically relevant
- Iron deficiency: tryptophan hydroxylase requires iron as cofactor; with iron deficiency reduced serotonin synthesis
Special considerations
Pregnancy and breastfeeding: tryptophan from food is unproblematic. Supplementation in pharmacologically high doses should be discussed with the treating doctor.
Children: tryptophan supplementation is rarely indicated in children; sleep problems should first be addressed non-pharmacologically.
Pre-existing conditions: with liver disease, renal impairment or neurological disease, consult a doctor before starting.
Realistic expectations: tryptophan is not a classic antidepressant or sleep medication in the pharmacological sense. Studies show moderate effects, especially with subclinical complaints. With clinically relevant depression or sleep disorder, established therapies should take priority.
Lifestyle: regular exercise, balanced diet, sleep hygiene, stress management and adequate light exposure are often as effective as tryptophan and should form the basis of any therapy.
Related substances
- Tryptophan, correct spelling
- Agomelatine, melatonergic antidepressant
- Zolpidem, short-acting hypnotic
- Buspirone, 5-HT1A partial agonist as anxiolytic
Frequently asked questions
Triptophan or tryptophan?
The correct form is tryptophan with the y. Triptophan is a spelling variant. Both refer to the same essential amino acid.
Does tryptophan make you tired?
Tryptophan can have a mild calming and sleep-promoting effect via serotonin and melatonin synthesis, especially combined with carbohydrate-rich food. The effect is much milder than with classic sleep medication and barely subjectively noticeable in many people.
What was eosinophilia myalgia syndrome?
In 1989 thousands of cases of eosinophilia and severe muscle pain occurred in the USA under a tryptophan product. The cause was a manufacturing impurity. The substance itself has since been considered safe, provided purity is ensured. Today's approved preparations are strictly controlled.
Can I get tryptophan from diet?
Yes. Rich sources are turkey, chicken, fish, dairy, eggs, nuts, legumes, soy products and chocolate. A balanced diet usually covers the requirement entirely. Supplementation only makes sense for specific indications or complaints.
Sources
- German Nutrition Society reference values
- BfArM Federal Institute for Drugs and Medical Devices
- BfR Federal Institute for Risk Assessment
- Gelbe Liste tryptophan monograph
Legal notice and disclaimer
The information on this page is provided for general information purposes only and does not constitute medical advice, diagnosis or treatment recommendation. It does not replace the advice of a licensed physician or pharmacist. Medicines should only be used after a doctor's prescription or pharmacy supply. All information is based on summaries of product characteristics and accepted scientific sources at the time of writing; the current SmPC of the manufacturer is always decisive. Sanoliste accepts no liability for completeness, timeliness or accuracy. In a medical emergency, dial the emergency number 112.