what you need to know about tryptophan(L-tryptophan)

A total of 20 naturally occurring amino acids play a fundamental role in animal and human nutrition and health, L-tryptophan is one of them. it is more precisely called an “essential” amino acid since the body cannot make it. It must be taken from dietary sources.

After consumption, it is metabolically transformed to bioactive metabolites, including serotonin, melatonin, kynurenine, and the vitamin niacin (nicotinamide).

Serotonin is a chemical in the brain that can affect mood. Eating foods that contain the essential amino acid known as tryptophan can help the body to produce more serotonin.

Melatonin is a natural hormone which your body produces by the pineal gland (located inside brain). It helps control sleep cycle. The body produces melatonin just after sunset, peaking in the early midnight and reducing during daytime. Melatonin acts on receptors in body to encourage sleep.

l-Kynurenine is also a metabolite of this amino acid which is used in the production of niacin.

Niacin(Vitamin B3) is one of eight B-complex water-soluble vitamins. Niacin has a range of uses inside body, it helps functions in the digestive system, skin and nervous system. Niacin, a name coined from nicotinic acid vitamin, comes in several forms, including niacinamide (nicotinamide) and inositol hexanicotinate. Each of these forms has various uses as well.

Nicotinamide, also known as niacinamide or nicotinic acid amide, is the water-soluble, active form of vitamin B3. although It has been studied for different factors in the field of dermatology, still more research is needed to certify its value.

What fitness and health benefits does amino acid tryptophan have?

research shows that L-tryptophan can improve power during exercise if taken before each session and can able you train with more intensity and focus(since serotonin raises focus and meditation phase)but research has not still found any benefit for people doing long cardio training and taking this amino acid and it seems like tryptophan helps with fast-twitch muscle fibers rather than slow–twitch muscle fibers.

L- tryptophan and its metabolites(serotonin, melatonin, kynurenine, and the vitamin niacin (nicotinamide) seem to have the potential to help people suffering from chronic kidney disease , cognitive function, autism, inflammatory bowel disease and microbial infections, cardiovascular disease, multiple sclerosis, renal cell carcinoma, depression. Tryptophan can also facilitate the diagnosis of certain conditions such as human cataracts, colon neoplasms and the prognosis of diabetic nephropathy.

Also it has been shown helpful to Treat premenstrual dysphoric disorder (PMDD). Taking 6 grams of L-tryptophan per day may decrease mood swings, tension, and irritability with PMDD.

And since it helps with mood with serotonin production, it has been shown to help people struggling with addiction and drug abuse especially cigarette smoking.

Best food sources of amino acid tryptophan

The recommended daily intake(RDA) for tryptophan is 4mg per Kg or 1.8mg per Lbs of body weight.

The foods mentioned below are some of the highest sources of L-tryptophan and the number inside parenthesis is the amount of this amino acid in 100 grams.

Chicken or Turkey(404mg)



Kidney beans(178mg)




Cashews and pistachios(240mg)