The Science Behind the Natural Sedative in Meat: What is Tryptophan?

November 14, 2025 •

3 min read

The notion that the tryptophan in turkey acts as a natural sedative in meat, making you sleepy after a big meal, is a widespread myth, often exaggerated around holidays. In reality, the effect is far more complex and involves a chain reaction of brain chemicals and digestive processes, not just the meat itself.

Quick Summary

The amino acid L-tryptophan is the natural sedative in meat, acting as a precursor to serotonin and melatonin. Its sleep-inducing effects depend on other dietary factors and competition with other nutrients.

Key Points

Tryptophan is the key amino acid: The 'natural sedative in meat' is the amino acid L-tryptophan, a precursor to serotonin and melatonin, which help regulate sleep.
Brain access is competitive: Tryptophan must compete with other amino acids to cross the blood-brain barrier, making the amount in a typical meal unlikely to cause noticeable drowsiness on its own.
Carbs are the real trigger: High-carbohydrate foods boost insulin, which removes competing amino acids and allows more tryptophan to enter the brain, contributing to post-meal sleepiness.
The 'food coma' is more complex: Post-meal fatigue is typically caused by large portion sizes, high carbohydrate intake, and potentially alcohol, rather than just the tryptophan in meat.
Variety is key: Many foods, including other meats, fish, nuts, and seeds, also contain tryptophan, often in higher concentrations than the famously cited turkey.
Meal timing matters: Eating heavy, protein-rich foods like red meat late in the evening can disrupt digestion and interfere with sleep, so timing is important.

The Amino Acid at the Center: Tryptophan

Tryptophan is an essential amino acid, meaning the human body cannot produce it and must obtain it from dietary sources. It is one of the building blocks of protein and plays a crucial role in many bodily functions beyond just forming muscle tissue. When we consume meat, we are ingesting a source of this important compound. While meat is an excellent source of tryptophan, it is not uniquely high in this amino acid compared to other protein-rich foods.

Why Tryptophan isn't an Instant Knockout

The reason the tryptophan in your dinner doesn't make you immediately sleepy lies in the blood-brain barrier, a protective mechanism that regulates what enters the brain. For tryptophan to cross this barrier and have a central effect, it must compete with other large neutral amino acids (LNAAs) that are also abundant in protein-rich foods. In a typical meal featuring meat, the high concentration of competing amino acids significantly limits the amount of tryptophan that can reach the brain.

From Tryptophan to Sleep Hormones

Once tryptophan successfully crosses the blood-brain barrier, it is converted into several neurochemicals vital for sleep regulation. The pathway is a multi-step process:

Conversion to 5-HTP: L-tryptophan is first hydroxylated by an enzyme called tryptophan hydroxylase, a rate-limiting step, to produce 5-hydroxytryptophan (5-HTP).
Synthesis of Serotonin: The 5-HTP is then converted into serotonin, a neurotransmitter that regulates mood, appetite, and sleep.
Production of Melatonin: Serotonin can be further converted into melatonin in the pineal gland, a hormone that regulates the body's circadian rhythms and helps signal the brain that it's time to sleep.

The Truth About the Food Coma

The post-meal drowsiness, or "food coma," often attributed to the tryptophan in meat, is much more likely caused by the high intake of carbohydrates and overall volume of food. When you consume a carbohydrate-heavy meal, your body releases insulin to regulate blood sugar levels. Insulin effectively removes the competing LNAAs from the bloodstream, allowing more of the available tryptophan to enter the brain. This, combined with the general digestive process requiring a lot of energy, is the more scientifically plausible cause of post-meal fatigue, not the meat alone. Alcohol consumption also contributes significantly to this drowsy feeling.

Tryptophan Content Across Different Meats

While meat contains tryptophan, it is important to remember that it is not exclusive to turkey. Many other animal and plant-based foods contain this amino acid, some in higher amounts.


Food (per 100g, approx.)	Tryptophan Content (mg)	Notes
Elk Meat (cooked)	545	Gamier meats often contain more.
Chicken Breast (roasted)	507	A high source of protein and tryptophan.
Pork Tenderloin (roasted)	274	A good source often overlooked in the sleep conversation.
Sockeye Salmon	335	Excellent source of tryptophan and omega-3s.
Turkey Breast (roasted)	318	The classic, but not superior, source.
Beef (roast, approx.)	229	Another solid meat source of this amino acid.
Yellowfin Tuna	252	High concentration of tryptophan among seafood.

Maximizing Tryptophan's Benefits for Sleep

Rather than relying on a single meal to induce sleep, a more balanced approach is needed. Incorporating tryptophan-rich foods alongside moderate carbohydrates can enhance the amino acid's transport to the brain. For example, pairing a smaller portion of lean meat or fish with a serving of rice or sweet potatoes may be more effective. Eating lighter meals earlier in the evening also supports better digestion, preventing it from interfering with sleep onset. For additional support, other food sources of sleep-regulating compounds can be included in your diet. Melatonin and magnesium-rich foods like tart cherries, kiwifruit, and nuts have also shown promise in promoting restful sleep.

Conclusion: More Than Just the Meat

The idea of a single "natural sedative in meat" simplifies a much more intricate physiological process. While the amino acid tryptophan is the foundational building block for sleep hormones like serotonin and melatonin, its path to inducing drowsiness is complicated by nutrient competition and other metabolic factors. The tired feeling after a large meal is likely a result of the collective impact of portion size, carbohydrate intake, and alcohol, rather than just the tryptophan from the meat. A balanced diet and lifestyle, rather than reliance on a single food item, are key to supporting healthy sleep patterns, and understanding the science can help demystify some of these enduring nutritional myths. For deeper insights into the complex relationship between nutrients, mood, and sleep, you can explore scientific reviews like this one from the National Institutes of Health.

Frequently Asked Questions

No, the common myth that the tryptophan in turkey makes you sleepy is largely untrue. The amount of tryptophan in turkey is not significantly higher than in other meats, and its effect is minimal in the context of a large meal filled with competing amino acids.

The feeling of tiredness after a large meal, often called a 'food coma', is primarily caused by overeating, especially high-carbohydrate foods, and alcohol, rather than the tryptophan in the meat.

Tryptophan is used by the body to produce serotonin and melatonin. Serotonin is a neurotransmitter that helps regulate mood and sleep, while melatonin is a hormone that controls the sleep-wake cycle.

Yes, tryptophan is an essential amino acid, so it is found in all protein-containing foods, including various meats, poultry, fish, eggs, cheese, nuts, and seeds.

You can potentially increase tryptophan's effects by pairing protein-rich foods with carbohydrates. The insulin released from carbs helps reduce the levels of competing amino acids in the bloodstream, allowing more tryptophan to reach the brain.

It depends on the type and portion. Heavier, fattier meats like red meat can be difficult to digest and may interfere with sleep. Lighter, leaner proteins are generally a better choice if you eat close to bedtime.

Yes, many foods are known to promote sleep. Examples include nuts and seeds (magnesium), fatty fish (omega-3s), milk, tart cherries (melatonin), kiwifruit, and oats.