Does L-tryptophan work? (3+ benefits)

In this article, we will discuss the working of L-tryptophan. Furthermore, we will explore what research suggests on this, the potential health benefits of L-tryptophan, its effectiveness in enhancing mood and improving sleep quality, risks or potential side effects, recommended dosage and factors to consider while using L-tryptophan supplements. 

Does L-tryptophan work? 

Yes, L-tryptophan can work effectively in some individuals. However, the effectiveness of L-tryptophan may vary among individuals as everyone is unique and responds differently to medications, supplements and dietary sources. (1)

L-tryptophan is considered an essential amino acid that can’t be produced by your body on its own, rather you have to incorporate it in your diet. It is the precursor of serotonin, which means it helps in the synthesis of an important neurotransmitter that plays a crucial role in regulating your sleep, mood and appetite. (1)

You can assess L-tryptophan through both, dietary sources like cereals, milk or nuts and over-the-counter supplements. It’s important to keep in mind that supplements must be used cautiously and other the guidance of your doctor to avoid any harmful interactions with food or other medications. (1,2)

How is L-tryptophan absorbed in your body?

L-tryptophan is absorbed in your body through a process called active transport. When you eat L-tryptophan-rich foods like meat, poultry, dairy products, nuts etc, the protein is broken down into individual amino acids with the help of stomach acid and some digestive enzymes. They are further broken down in the small intestine and ultimately L-tryptophan is absorbed into the bloodstream. (2)

L-tryptophan can cross the blood-brain barrier and in the brain, it serves as a precursor for serotonin. Serotonin exerts its effects by improving one’s mood and it may also influence melatonin regulation, which is a hormone responsible for your sleep-wake cycle. (2)

Any excess or unused L-tryptophan can be eliminated from your body through urine. However, it’s important to remember that certain factors may influence the absorption or removal of excess L-tryptophan from your body. So it’s crucial to consult a healthcare provider before starting any supplement.

What does research suggest?

According to research, a randomized control trial was conducted by researchers to determine the effectiveness of L-tryptophan on depressive patients with no other major health conditions. They found out that L-tryptophan is an effective approach to reduce the symptoms of anxiety and promote positive feelings. (3)

The people who took L-tryptophan supplements felt more happy and more relaxed compared to those who didn’t take it. After reviewing 11 controlled trials, they concluded that taking 0.14-3 grams of L-tryptophan per day along with regular meals, appeared to help improve mood and reduce depression and anxiety. (3)

What are the potential health benefits of L-tryptophan?

Here are some potential benefits of L-tryptophan: (1)

Mood regulation: L-tryptophan helps your body make serotonin, a happy hormone which makes you feel good and improves overall mood. 

Sleep improvement: Serotonin, synthesized from L-tryptophan is capable of converting into melatonin which is a hormone that regulates your sleep-wake cycle. In this way, L-tryptophan helps improve your sleep quality and can be given to insomniac people as well. 

Stress reduction: Serotonin is thought to play a crucial role in managing stress. Sufficient levels of serotonin boost your confidence and help the body cope with stress, thereby reducing the risk of depression and anxiety.

Appetite regulation: L-tryptophan can also be linked to appetite regulation through serotonin production. It is also found to be effective in weight management. 

Cognitive functions: Serotonin produced by L-tryptophan is involved in various cognitive functions like it improves memory and learning. It helps to reduce confusion and enhances focus, thus having a positive impact on cognitive performance. 

Pain management: L-tryptophan may help in pain management as serotonin is involved in pain perception. Some studies have shown its potential use in chronic pain conditions.

What are the risks and potential side effects of L-tryptophan? 

L-tryptophan is usually considered safe when taken through a balanced diet but taking its supplements might cause certain side effects. It’s important to be aware of these potential issues before starting L-tryptophan supplements: (4)

Allergic reactions: Some individuals may be more sensitive or allergic to the use of L-tryptophan and experience symptoms like itching, swelling or rashes on the skin and difficulty in breathing. So if you experience any allergic reaction, it is recommended to talk to your doctor.  

Serotonin syndrome: If you consume L-tryptophan supplements in high amounts for a prolonged time or combine them with certain medications that increase serotonin levels like antidepressants including Luvox, Citalopram etc, this may lead to a life-threatening condition called serotonin syndrome. Its symptoms might include fever, hallucinations, confusion rapid heartbeat, seizures etc.

Gastrointestinal issues: Some people may experience gastric issues like nausea, vomiting or diarrhoea while taking L-tryptophan supplements. So it’s better to take them with a meal with less protein content and rich in carbs. 

Interaction with medications: L-tryptophan can also interact with medications like antidepressants, antipsychotics or others that affect serotonin levels. This may lead to excessive accumulation of serotonin which can be harmful. 

Pregnancy and breastfeeding: Women who are pregnant or breastfeeding must consult their healthcare providers before starting this supplement to ensure the safety of use. (5)

What is the recommended dose of L-tryptophan to minimize side effects?

The recommended dose of L-tryptophan supplements may vary depending on the individual’s specific health status, how much deficient they are of the essential amino acid and the specific product or formulation. The normal prescribed dose of L-tryptophan supplements generally ranges from 500-2000 mg per day. (3,5)

As a pharmacist, I would suggest you always stick to the recommended dosage regimen provided by your doctor and do not adjust the dose or decide the period of course on your own. It’s usually better to start with a low dose of supplement like 500mg per day and then gradually increase the dose over time if needed and observe how your body is responding. 

You need to be mindful of the possible interactions, so don’t start any other medication while you’re taking the supplements without your doctor’s approval. It’s better to obtain L-tryptophan through dietary sources which are safer rather relying solely on supplements. 

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National Library of Medicine. MedlinePlus Drug Information. L-tryptophan, [Internet]. Available from: