What is tryptophan?  

Tryptophan is an essential amino acid that’s used by the body for muscle growth and to produce niacin, which in turn produces serotonin. There are actually two types of tryptophan: L-tryptophan and D-tryptophan, but the differences are largely unimportant for the layperson when it comes to benefiting from tryptophan. The recommended daily intake of tryptophan is 1.8mg per pound, so around 250mg a day for a 140lbs person.  

How does tryptophan affect my health?  

Recent studies have found that it can play a role in the therapy of cardiovascular disease, as well as chronic kidney disease, multiple sclerosis, and inflammatory bowel disease. It’s also been seen to have the potential to contribute to the therapy of cognitive issues such as autism, sleep, social function, and other cognitive functions.  

Tryptophan became popular for those looking to build muscle because it has been seen to increase lean muscle mass and decrease body fat, though it’s worth noting that most studies on this have been on rodents.  

Tryptophan is particularly noteworthy in its use in the production of serotonin – in fact, it’s the sole precursor of serotonin. Research has found that withdrawal of tryptophan (called tryptophan depletion) can incite depressive periods, though interestingly, more so in those that have already experienced depression or anxiety in the past.  Studies have seen that loading tryptophan in the diet increases the rate of serotonin synthesis in the brain, which in turn improves mood stabilization and decreases incidences of depression and anxiety.  

Tryptophan is found in protein, so naturally, it’s found in protein-rich foods such as:  

• Chicken & turkey breast (687mg in a 6oz breast)  

• Lean pork (in a 6oz Chop, 627mg)  
• Tofu (592mg per cup of uncooked firm tofu)  
• Salmon (570mg per 6oz fillet)  
• Lean, boneless, almost fatless rib-eye beef steak (378mg per 100g)  
• Mozzarella (603mg per 100g)  

• Pumpkin seeds (576mg per 100g)  
• Parmesan (560mg per 100g)  
• Chia seeds (436mg per 100g)  
• Tahini (393mg per 100g)  
• Sesame seeds (388mg per 100g)  

• Cheddar cheese (320mg per 100g)  
• Montery cheese (315mg per 100g)  

It’s also found in high protein vegetable sources, such as broccoli (30mg per 1 cup chopped but uncooked), but in much smaller amounts:  

• Seaweed (929mg per 100g)  
• Sweet peppers (229mg per 100g)  
• Leeks (117mg per 100g)  
• Spinach (100mg per 100g)   
• Potatoes (98mg per 100g)  

You’ll even find traces of it in herbs and spices like paprika (70mg per 100g), onion powder, black pepper, cinnamon, fresh basil, and dill. 

Dr. Nancy Rahnama, MD, ABOM, ABIM, is a medical doctor board certified by both the American Board of Obesity Medicine and the American Board of Internal Medicine. Her specialty is Clinical Nutrition, that is, the use of nutrition by a medical doctor to diagnose and treat disease. Dr. Rahnama has helped thousands of people achieve their goals of weight loss, gut health, improved mood and sleep, and managing chronic disease.