Mastering the time change with ease: How L-tryptophan helps your internal clock stay on track

Imagine your alarm clock goes off, but your body has its own idea of what time it is. Every year, the time change—that little jump from Central European Summer Time back to Central European Time (CET)—throws us off balance for a moment. It's that moment, usually on the last Sunday in October, when we “gain” an hour, but our entire rhythm feels like jet lag.

But what if we could gently counteract this shift with a small but essential amino acid? The key to relaxation during this transition period often lies in consciously supporting our body's own mechanisms. In the following sections, we will take a look at how the amino acid L-tryptophan, an essential building block for serotonin and melatonin, can help to calmly synchronize the day-night rhythm [1]. We explain how this amino acid works in the human body and how you can make the most of it to strengthen your internal clock and start November without feeling jetlagged.

When your internal clock is an hour off: The challenge of daylight saving time

The annual clock change is a routine part of civilization. The Physikalisch-Technische Bundesanstalt (PTB) ensures that the legal time is observed in Germany, but our bodies have to find their own rhythm. When the clocks jump back from 3:00 a.m. to 2:00 a.m., the seemingly “gained” hour of sleep causes biological disorientation. This is referred to as “mini jet lag” because the change between summer time and winter time severely disrupts our sleep-wake rhythm. This change in rhythm can be particularly difficult for small children at first [2].

The strategy of gentle adjustment

When the clock changes, the body needs clear and consistent orientation signals to gently bring the day-night rhythm back into sync. A healthy lifestyle with conscious routines is essential here.

Actively shape your evening window: consciously shift your bedtime by one hour.

Set signals: Use warm, subdued lighting, avoid scrolling in bed (no blue light!), and send your body the signal to relax through rituals such as a cup of tea.

Recharge your batteries: Combine this with a short breathing routine (for example, inhale for 4 seconds, exhale for 6 seconds).

Use daylight in the morning: Bright light (windows and curtains open) in the morning synchronizes the internal clock and signals to the body that the day has begun.

This conscious control of habits can be supported by providing essential building blocks that the body needs to produce its own pacemakers. This is exactly where L-tryptophan comes into play. It is considered the natural companion to falling asleep [3].

The essential amino acid L-tryptophan

The amino acid L-tryptophan is much more than just a building block: it is a true hub for our well-being and sleep. It is considered an essential amino acid, which means that the human body cannot produce it itself. We are dependent on a sufficient supply through a varied diet [4].

The conversion: From tryptophan to the feel-good duo

The main function of tryptophan lies in its role as a biochemical precursor for two of the body's most important messenger substances, which control our mood, behavior, and sleep-wake cycle [4]:

Serotonin (5-HT): The proteinogenic amino acid L-tryptophan is first converted into 5-hydroxytryptophan and then decarboxylated to serotonin. Serotonin is a central neurotransmitter that influences cognition, mood, and appetite in the brain. A balanced serotonin level is crucial for emotional balance and general well-being. If serotonin levels drop, this can lead to depressive moods.

Melatonin: Serotonin, in turn, serves as a direct precursor for the sleep hormone melatonin, which is produced in the pineal gland. Melatonin is the primary regulator of our circadian system and signals to the body that it is time to sleep.

Due to this chain of conversions, L-tryptophan is considered essential for optimal body function, especially in relation to the psyche and sleep cycle. It is therefore a basic substance that we should definitely keep at a high level, especially when external shifts in rhythm are imminent [4].

You can find out more about tryptophan here.

Support for internal imbalances

The amino acid L-tryptophan is an important focus of research due to its role in our psyche and sleep cycle. It is known that health claims have been submitted to the European Union authorities to scientifically substantiate its positive effects.

Although these claims have not been recognized as official claims due to a lack of scientific basis, research shows the potential of L-tryptophan for your well-being:

Positive mood and serenity: As an essential precursor to serotonin, L-tryptophan is an important starting point in studies on maintaining a positive mood [5]. Especially during dark periods or when the body is stressed by time changes, supporting serotonin availability can help counteract depressive moods.

Stress relief: Studies also suggest that L-tryptophan can improve the body's ability to cope with stress. There is evidence that it can attenuate the cortisol response [4]. This is an important factor when the internal clock is stressed by external rhythm shifts.

The journey to the brain: How tryptophan reaches its destination

In order for L-tryptophan to fulfill its important function as a precursor for serotonin and melatonin in the central nervous system, it must overcome a highly selective barrier: the blood-brain barrier. This transport mechanism is the key to maximizing the effect of tryptophan [4].

The strategy: tryptophan versus the competition

The key biochemical detail is the competition at the blood-brain barrier. L-tryptophan competes with other large, neutral amino acids (L-tyrosine is one of them), which are also found in protein-rich foods. High levels of these competitors in the blood can hinder the transport of tryptophan into the brain because the transporters become saturated [4].

This provides the answer to the question of when L-tryptophan should ideally be taken to increase serotonin levels in the brain [4]:

Time separation: Ideally, take L-tryptophan capsules separately from protein-rich meals.

The carbohydrate trick: It should be taken on an empty stomach or with a small, carbohydrate-rich component (e.g., a piece of fruit or a small snack).

Carbohydrates lead to the release of insulin. Insulin not only helps with sugar metabolism, but also transports competing amino acids to the muscles. This increases the relative concentration of tryptophan in the blood plasma in relation to its competitors. This high relative proportion makes it easier for the amino acid L-tryptophan to cross the blood-brain barrier and stimulate neurotransmitter synthesis in the brain [6].

The necessary helpers: B vitamins

For effective serotonin and melatonin synthesis, the body also needs essential cofactors, especially B vitamins, above all vitamin B6. B vitamins are important for countless enzymatic reactions, including conversion to serotonin. Combining L-tryptophan capsules with B vitamins can therefore optimize bioavailability and effectiveness [7].

Tryptophan deficiency: When the building block is missing

As an essential amino acid, tryptophan must be supplied to the body in sufficient quantities. The recommended daily intake for adults is considered high, estimated at between 3.5 and 6.0 mg per kilogram of body weight per day [4].

A tryptophan deficiency leads to reduced availability of the precursors for serotonin and melatonin. So how can you tell if you have a tryptophan deficiency? The symptoms typically manifest themselves in the areas controlled by these neurotransmitters [8]:

Sleep disorders: Reduced melatonin production can directly lead to sleep disorders in the day-night rhythm.

Mental imbalances: An imbalance of neurotransmitters can lead to increased anxiety and susceptibility to stress and depressive moods.

Weakened immune system: Tryptophan also plays a role in the immune system; a deficiency can increase susceptibility to infections.

The primary source of tryptophan is a varied diet. Taking supplemental tryptophan preparations may be considered in certain situations, such as time changes or increased stress. The recommended dose for prescription preparations to promote sleep readiness is often 1 g of tryptophan (equivalent to 1000 mg) [4].

Foods rich in tryptophan [4]:

Dairy products: Emmental cheese (contains approx. 500 mg/tryptophan per 100 g)
Nuts/seeds: Sunflower seeds (contains approx. 290 mg/tryptophan per 100 g)
Cereals: Oatmeal (contains approx. 180 mg/tryptophan per 100 g)
Animal products: Eggs (contains approx. 170 mg/tryptophan per 100 g)

Safety and purity: What you need to know

The question of whether L-tryptophan capsules can be taken without hesitation requires a differentiated consideration of safety aspects, interactions, and historical background. In principle, pure L-tryptophan is considered a safe essential amino acid if the recommended intake is observed and interactions are ruled out [9].

The intended fatigue and tolerability

Does tryptophan make you tired? Yes, one of the intended effects of tryptophan, which promotes relaxation and provides the body with the precursor for melatonin, often leads to a certain drowsiness when taken. Therefore, evening intake is preferred to support the sleep-wake cycle [10].

L-tryptophan can be taken daily as long as the recommended dosage in mg is adhered to and there are no contraindications. Excessive amounts can cause side effects in some people, including headaches or dizziness [4].

Serotonin syndrome

The most important safety risk when taking tryptophan supplements concerns interactions with medications that also affect serotonin levels in the brain [11].

What should not be mixed: Combining L-tryptophan with certain antidepressants or serotonergic substances can lead to potentially life-threatening overstimulation of the serotonin system, known as serotonin syndrome [11].

The simultaneous use of L-tryptophan with the following is strictly contraindicated [11]:

Selective serotonin reuptake inhibitors (SSRIs).
Tricyclic antidepressants.
MAO inhibitors (monoamine oxidase inhibitors).

Symptoms of serotonin syndrome include extreme anxiety, severe muscle spasms, delirium, and hyperthermia. Individuals taking psychotropic medications must consult a physician before taking tryptophan [11].

Key questions about L-tryptophan and your balance

To ensure a comprehensive understanding of the effects and uses of tryptophan, we answer the most frequently asked questions from our readers here.

What is L-tryptophan good for?

L-tryptophan is an essential amino acid that serves as a precursor for serotonin (mood, cognition) and melatonin (sleep-wake cycle). It can contribute to a positive mood and relaxation [4].

Does tryptophan make you tired?

Yes, by promoting melatonin production, tryptophan can cause drowsiness and fatigue. That is why it is often taken before bedtime to accompany the natural onset of sleep [10].

Does L-tryptophan increase dopamine?

No, L-tryptophan is the precursor to serotonin. Dopamine is synthesized from another essential amino acid, L-tyrosine [4].

Is L-tryptophan better than melatonin?

They serve different purposes. L-tryptophan provides the body with the building block it needs to produce its own sleep hormone, melatonin, as required. Compared to exogenous administration of the hormone, this can have a gentler effect on the day-night rhythm [4].

Can tryptophan be taken by young children?

There is insufficient data on the safety of supplementation in young children. It should only be used under strict medical supervision and on the advice of a doctor.

When does the clock change to winter time?

The change to winter time (CET/Central European Time) always takes place on the last Sunday in October throughout the European Union and EU countries.

What is tryptophan 2,3-dioxygenase?

Tryptophan 2,3-dioxygenase is an important enzyme involved in the breakdown of free tryptophan. Its activity can be highly regulated by certain circumstances (such as inflammation), which can lead to less tryptophan being available for the synthesis of serotonin [12].

Gently back into rhythm

We have seen that the time change poses a small challenge for our human body and internal clock, but with the right routines and nutrients, it can be mastered in a relaxed manner.

The key lies in mindfulness: conscious signals in the evening, warm light, rituals, and half an hour without media help the body prepare for sleep. And this is exactly where the essential amino acid L-tryptophan becomes a valuable companion. As an indispensable precursor for the feel-good duo serotonin and the sleep hormone melatonin, tryptophan naturally supports your body in finding its day-night rhythm [4].

Remember: after a few evenings, you will find your rhythm again. So you can feel that November can start without jet lag. It is up to you to make it a peaceful time with a healthy lifestyle and the right building blocks.