Ingredient guide
L-tryptophan is an essential amino acid the body uses to make serotonin and melatonin. Trials at 1 g or more support better sleep and a calming effect on mood. It has a complicated history due to the 1989 EMS outbreak from a contaminated batch.
Moderate evidenceL-tryptophan is one of the nine essential amino acids your body cannot make on its own. You get it from protein foods, especially turkey, chicken, eggs, dairy, oats, and seeds. In the brain, it is the sole raw material for making serotonin, the neurotransmitter that influences mood, sleep, appetite, and pain perception, and is in turn the precursor of melatonin, the sleep hormone.
Tryptophan competes with other amino acids to cross the blood-brain barrier, which is why a meal high in protein but low in carbohydrate does not raise brain serotonin much. Taking it on its own between meals raises tryptophan levels in the brain and supports serotonin and melatonin production over the following hours.
A review of clinical research found that oral tryptophan can shift mood in the direction of relaxation and lower perceived stress, with the effect linked to increased serotonin in the central nervous system. An older clinical trial in severe chronic insomnia using L-tryptophan reported markedly improved sleep in 76 percent of subjects between days 10 and 15.
More recent work has refined our understanding. Genetic differences in serotonin metabolism mean responses vary between people. The evidence is also marked by the 1989 EMS (eosinophilia-myalgia syndrome) outbreak traced to a single contaminated batch, which led to a temporary ban. Modern, properly produced tryptophan is considered safe at typical doses. We grade the evidence as moderate, with the strongest case for sleep and mild stress at 1 g or more.
Take 1 g to 5 g between meals, often before bed for sleep, to avoid competition with other amino acids. Choose third-party tested products. Never combine it with SSRIs, MAOIs, or other serotonin-affecting medicines without a doctor's input, due to the risk of serotonin syndrome.
Trials commonly use 1 g to 5 g of L-tryptophan per day, often before bed for sleep. Take between meals, since other amino acids compete for absorption into the brain. Ask your healthcare provider before regular use if you take antidepressants or any serotonin-affecting medicine.
Trials and reviews support better sleep at 1 g or more, especially in people with sleep complaints. Take it before bed between meals.
No, not without medical input. Combining tryptophan with SSRIs, MAOIs, or other serotonin-affecting drugs can cause serotonin syndrome.
It contains tryptophan, but the famous Thanksgiving drowsiness is mostly about a big meal and carbohydrate, not just turkey tryptophan, which is not absorbed well after food.
Yes, in modern properly produced form. A 1989 outbreak was traced to one contaminated batch, which led to better manufacturing and safer products today.
