Use Tryptophan to Boost Serotonin for Better Mental Health

Edited and medically reviewed by Patrick Alban, DC | Written by Deane Alban

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Boosting serotonin levels with tryptophan can improve depression, anxiety, ADHD, memory loss and more. Learn how tryptophan supplements and foods can help.

Every Thanksgiving, tryptophan gets its 15 minutes of fame as the amino acid in turkey that makes you tired.

(Contrary to popular belief, it’s the massive amount of carbs — not turkey — that’s responsible.) (1)

For the rest of the year, tryptophan is largely ignored, and that’s unfortunate …

Because it’s an essential building block for serotonin, an important mood-boosting brain chemical.

Yet, due to a biological quirk, very little dietary tryptophan is available for serotonin synthesis.

For many people, this may not be a problem.

But depression, anxiety, ADHD, memory loss, binge eating, and a host of other mental health issues have been correlated to a low level of tryptophan.

So a lack of bioavailable tryptophan may have a big impact on your life.

Read on to learn how to strategically use food and tryptophan supplements to optimize serotonin levels.

How Tryptophan Raises Serotonin Levels

Tryptophan is an essential amino acid needed to synthesize serotonin, the neurotransmitter dubbed the “happy molecule.”

You can see the pathway of serotonin synthesis from tryptophan in the diagram below.

diagram of the tryptophan-serotonin synthesis pathway
The pathway of tryptophan-serotonin synthesis. (Image courtesy of Dr. Katherine Chung)

Serotonin plays a large role in mood, sleep, learning, and appetite control.

Low serotonin is widely believed to be a major cause of depression.

The most popular antidepressant medications like Prozac and Zoloft are selective serotonin reuptake inhibitors (SSRIs) which work by making more serotonin available in the brain.

If you want more serotonin, you can’t just pop a “serotonin pill” since serotonin molecules are too large to enter the brain.

But you can increase serotonin levels by providing more of its raw material in the form of tryptophan instead.

Key Role of Tryptophan in 10 Mental Health Disorders

By increasing serotonin levels, tryptophan can improve the quality of life for people who have a surprising variety of brain-related and mental health issues. (2)

1. Tryptophan and Depression

Studies have found tryptophan to be as effective for depression as antidepressant drugs. (3)

This is an exciting discovery for the millions of people for whom antidepressants either don’t work or have unacceptable side effects.

Note: Do not mix SSRIs and tryptophan without talking to your doctor. When taken together, they can cause serious side effects.

2. Tryptophan and Anxiety

Tryptophan has been found useful for reducing general anxiety, social anxiety disorder, and panic attacks. (4)

3. Tryptophan and ADHD

Both low levels of tryptophan and serotonin imbalances are associated with attention deficit hyperactivity disorder (ADHD).

Children with ADHD have 50% lower than average blood levels of tryptophan. (5)

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4. Tryptophan and Memory Loss

Low tryptophan can cause long-term memory loss and impair other cognitive functions. (6)

Tryptophan has been found to improve memory in both healthy adults and those with depression.

5. Tryptophan and PMS

Ladies, if your family tries to avoid you when it’s “that time of the month,” you might benefit from additional tryptophan.

Tryptophan can offer significant relief from premenstrual syndrome (PMS) symptoms like mood swings and irritability. (7)

6. Tryptophan and Bipolar Disorder

Tryptophan supplements can alleviate the depression that accompanies bipolar disorder by increasing serotonin levels.

It’s not as effective as lithium and doesn’t help mania, so it won’t replace, but can support, conventional medical treatment.

Tryptophan can reduce symptoms of tardive dyskinesia, a common side effect of antipsychotic drugs. (8)

If you are bipolar, seek the help of a medical professional before adding a tryptophan supplement to your supplement regimen.

7. Tryptophan and Obsessive-Compulsive Disorder

SSRIs are sometimes used to treat obsessive-compulsive disorder (OCD).

Tryptophan enhances the effects of SSRIs when taken for OCD. (9)

It has been found to be especially helpful when taken with niacin and vitamin B6, a cofactor needed to turn tryptophan into serotonin.

8. Tryptophan and Seasonal Affective Disorder

The usual treatment for seasonal affective disorder (SAD) is exposure to light.

But if light therapy alone doesn’t help, try upping your intake of tryptophan.

When tryptophan is taken either on its own or along with light therapy, it can reduce the symptoms of SAD. (10)

9. Tryptophan and Eating Disorders

Dieting causes low tryptophan and serotonin levels, especially in women.

This can lead to increased cravings and binge eating since serotonin helps regulate appetite and food intake.

People with bulimia tend to have low serotonin levels.

It’s believed that low levels of tryptophan and serotonin trigger bulimics’ binge eating too.

Tryptophan supplements, especially when taken with vitamin B6, can improve eating habits, feelings about eating, and mood. (11)

10. Tryptophan and Insomnia

Besides being the precursor to serotonin, tryptophan is also a building block of the sleep hormone melatonin.

Tryptophan can help you fall asleep faster, sleep longer, and awake less often in the night.

It can also produce significant improvements in obstructive sleep apnea.

Ideally, taking tryptophan at bedtime along with a small carbohydrate snack improves its uptake into your brain.

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The Dilemma of Increasing Serotonin with Tryptophan-Rich Foods

If you think you could benefit from more tryptophan, the next logical question is:

Should you try to get tryptophan from food or is it better to take a tryptophan supplement?

The best sources of tryptophan are animal products — meat, seafood, poultry, eggs, and dairy. (12)

But there is a big problem with trying to increase your level of tryptophan from these foods.

These foods are also all high in protein, but, paradoxically, both tryptophan and serotonin drop after eating a meal containing protein. (13, 14, 15)

This is because protein blocks the synthesis of tryptophan into serotonin.

The trick for working around this dilemma is actually quite simple though.

Strategic eating of carbohydrates alone (with no protein) at some of your meals allows tryptophan to enter your brain and boost serotonin levels.

There are a handful of relatively low-protein, tryptophan-rich foods you can include in your diet, such as spinach and other green leafy vegetables, sea vegetables, soybeans, asparagus, cauliflower, and sunflower or sesame seeds. (16)

According to the International Journal of Tryptophan Research, the top food sources of tryptophan proven to actually cross into the brain to synthesize serotonin are dairy products, poultry, tuna, and oatmeal. (17)

Why Supplemental Tryptophan Works Better Than Food

Of all the amino acids in your body, tryptophan is the least common and yet it’s needed in abundance to perform a variety of functions.

Stress, insulin resistance, magnesium deficiency, and increasing age affect your ability to turn tryptophan into serotonin. (18)

Even if you eat a lot of tryptophan foods, only a small amount — less than 1% — is available for serotonin synthesis in the brain.

For these reasons, taking a tryptophan supplement often works better than trying to get enough tryptophan from food alone.


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Tryptophan Safety, Side Effects, and Interactions

Tryptophan supplements were actually banned for some years following 1989 when a contaminated supplement batch caused thousands of side effects, including several fatalities. (19)

The ban was lifted years ago and, for the past 25 years, thousands of studies, with no safety issues, have been done on tryptophan.

It’s now well established that there is nothing inherently dangerous about tryptophan.

However, tryptophan is not right for everyone.

It should not be taken by anyone with liver or kidney disease and its safety has not been established for pregnant women or nursing moms.

The most common side effects of tryptophan are digestive upset, loss of appetite, headache, and drowsiness.

Tryptophan should not be taken along with SSRIs or supplements that increase serotonin such as 5-HTP or SAM-e (S-adenosylmethionine).

When taken together, they can increase serotonin level too much, causing a potentially serious condition known as serotonin syndrome.

Additionally, tryptophan should not be taken with sedating drugs (sleeping pills, benzodiazepines) or supplements (kava, St. John’s wort, valerian).

When taken together, any of these combinations can cause excessive drowsiness.

If you are unsure whether any drugs or supplements you take should not be mixed with tryptophan, you’ll find a comprehensive list of interactions on MedlinePlus.

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Tryptophan Dosage

There is no official recommended dosage for tryptophan and suggested doses vary widely.

As little as 250 mg has been found to increase the quality of sleep.

On the other hand, Mayo Clinic recommends 8 to 12 grams per day for depression. (20)

Tryptophan is available either in capsules or as a loose bulk powder (which we recommend if you are taking large doses of it).

Most supplement manufacturers suggest a daily dose of 1,000 to 1,500 mg.

If you don’t know where to begin, we suggest starting with 500 mg a day and then working your way up to a higher dose as needed and tolerated.

3 Ways Tryptophan Is Superior to 5-HTP

Another way to raise serotonin levels is with the mood-enhancing supplement 5-HTP.

You may recall from the chart at the beginning of this article that tryptophan is first broken down into 5-HTP and is then converted to serotonin.

But there are three compelling reasons supplemental tryptophan is superior to 5-HTP:

  • Tryptophan more readily enters the brain than 5-HTP.
  • Studies have not conclusively proven that 5-HTP helps depression.
  • 5-HTP is not intended for long-term use.

This last drawback is a deal breaker.

5-HTP increases serotonin, but at a cost.

It simultaneously depletes other neurotransmitters such as dopamine, norepinephrine, and epinephrine. (21)

This is why 5-HTP works for some people for a while, but then suddenly stops working.

Within a few months, you may feel even worse than you did before you started taking 5-HTP.

Tryptophan and Serotonin: Take the Next Step

Tryptophan is an essential amino acid found mainly in high-protein animal foods.

It’s essential for the formation of serotonin — the neurotransmitter responsible for mood, sleep, learning, and appetite control.

Getting adequate tryptophan to create optimal levels of serotonin from food alone can be challenging.

There are many reasons for this, including the paradox that protein blocks the formation of serotonin.

There are two simple solutions: 1) strategically eat carbohydrates and/or 2) take a tryptophan supplement.

READ NEXT: Serotonin Deficiency: Signs, Symptoms, Solutions