L-Tyrosine
An amino acid turned into dopamine and noradrenaline, taken before a demanding moment.
- Focus and mental control
- Stress and pressure
- Endurance exercise
- Creative thinking
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
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On this page
What is L-Tyrosine?
L-tyrosine is an amino acid found in protein-rich foods and used by the body to build dopamine and noradrenaline, the chemical messengers tied to alertness and to how the body responds to a demanding moment. It is sold on its own as capsules or powder, either as plain L-tyrosine or as N-acetyl L-tyrosine (NALT), a more soluble form some sellers use instead. Most of the research behind it, and most of the interest in it, centre on brain performance under pressure: people reach for it before something that will test their concentration, their nerve, or both.
Why do people take L-Tyrosine?
Focus and mental control
The thinking. Dopamine and noradrenaline play a part in holding attention, switching between tasks and stopping an unwanted response, so the reasoning is that more of the raw material behind them might let these abilities hold steady under demand. People take it before something that will call heavily on concentration and self-control, such as an exam or a long, demanding shift.
What research has found. Four small trials tested tasks like these. Two found a benefit: tyrosine narrowed the extra time it took to switch between tasks, and made people more efficient at stopping a response they no longer needed to make. The other two found mixed results, in one case differing by a person’s genetic makeup. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Stress and pressure
The thinking. The same reasoning carries over to stress itself: noradrenaline is part of how the body reacts to pressure, so the thinking is that supporting its supply beforehand might soften how hard a stressful moment hits. Much of the research behind this reason tests people right before or during a demanding, high-pressure exercise, such as a training drill, rather than everyday stress.
What research has found. One trial put people through a demanding simulated emergency-response drill and found tyrosine made no difference to saliva stress hormones, heart rate or reported anxiety, though people taking it missed fewer responses on a stressful concentration task done during the drill. A second, smaller trial found a single dose lowered physical signs of arousal and sped up decision-making without people performing any worse. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.
Endurance exercise
The thinking. Tyrosine is also taken by some for physical stamina, particularly exercise that wears down the mind as much as the muscles, such as a long effort in the heat or after a mentally tiring day. The reasoning again rests on noradrenaline, which plays a part in how hard an effort feels, so the idea is that supporting its supply might let someone keep going.
What research has found. A meta-analysis pooling eight studies found no clear difference in time to exhaustion or time-trial performance, rating the evidence moderate quality. Trials since have mostly agreed, though one stood out: a small trial in cyclists who had just finished an hour of mentally tiring work found tyrosine let them cycle for longer with the effort feeling less taxing, while trials in soccer players and endurance-trained cyclists exercising in the heat found no difference in physical or decision-making performance. Research here is still young: a few studies so far, mostly pointing the same way.
Creative thinking
The thinking. A few people take tyrosine hoping it sharpens creative thinking rather than plain concentration, on the idea that some kinds of creativity call on the same top-down mental control as other demanding tasks, and so might respond to it in a similar way.
What research has found. The one trial to test this gave healthy adults two kinds of creative-thinking task: free brainstorming, and a more focused, puzzle-solving kind of thinking. It found no effect on the brainstorming task, but people did better at the focused thinking task after taking tyrosine. Few studies have measured this yet, so there is little to go on either way.
What does L-Tyrosine do in the body?
Tyrosine is the raw material the body uses to build dopamine and noradrenaline, the chemical messengers tied to alertness, motivation and how the body responds to a demanding moment. Reviewers describe these messengers as running low when the brain and body are under sustained pressure, and the reasoning behind taking tyrosine is that giving the body more of what it needs to keep making them might let performance hold up rather than fall away.
Reviewers are careful to say this is not a straightforward top-up: one review concluded tyrosine’s benefit shows up mainly in short, cognitively demanding or stressful situations, and mainly where the supply of these messengers has actually been run down, rather than as a general lift at any time. That is offered as the reason its trials so often test people right before or during a demanding task rather than on an ordinary day.
What do people say about taking L-Tyrosine?
These are anecdotes people have shared, not evidence.
What people like
- Feeling sharper or less foggy is the commonest positive report: several people describe clearer thinking or steadier focus after starting it.
- Mood came up unprompted too: one person taking it for an unrelated reason noticed feeling clearer-headed and happier as an unexpected side effect.
- A couple of people say they notice it by its absence, feeling less on-the-ball on the days they forget to take it.
- Menopausal brain fog is one setting where it comes up specifically, mentioned alongside other supplements taken for the same complaint.
Common complaints
- Anxiety is the complaint that recurs most in these threads: one strong reaction was enough to put another poster off trying it at all.
- Taking it daily is sometimes reported to disturb sleep; one person cut back to every other day to manage this.
- A few people say it made little difference to the anxiety or low mood they had hoped it would ease, and stopped taking it regularly.
- A couple of people mention being cautious before starting it at all, citing concerns about heart rate or an existing thyroid condition.
How people take it
- People in these threads commonly describe taking it first thing in the morning, on an empty stomach, before starting the day’s work.
- Pairing it with caffeine, taken at the same time in the morning, is a combination a couple of posters mention by name.
- It is often mentioned alongside other supplements, such as rhodiola or 5-HTP, rather than taken entirely on its own.
- Doses mentioned range from smaller amounts up to a standard 500 mg; not everyone takes it daily, and some keep it for occasional, as-needed use.
Read from these public discussions:
- Can I improve my ability to focus? (Mumsnet, 2023)
- Supplements that have helped brain fog/brain power. (Mumsnet, 2024)
- Supplements for mild anxiety and to lift mood (Mumsnet, 2019)
- L Tyrosine & 5Htp (Patient.info, 2018)
- Stress/Anxiety and its toll on memory and concentration (Patient.info, 2017)
What forms of L-Tyrosine are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| L-tyrosine | The plain amino acid on its own, the form almost all of the trials used. | 1 g |
| N-acetyl L-tyrosine (NALT) | L-tyrosine with an acetyl group attached, sold as a more water-soluble alternative to the plain form. | not in our price tables yet |
What else is worth knowing about L-Tyrosine?
- Where a trial stated its dose, it was often a large one: 150 mg per kilogram of body weight in some of the exercise trials, or a fixed 2 grams in some of the stress trials; labels give the amount per serving.
- A four-week trial testing doses up to 4 g a day in healthy men found no meaningful change in blood tests, and no more side effects than on a placebo.
- Phenelzine, a prescription antidepressant from the MAO inhibitor class, carries a warning against combining it with tyrosine, over a theoretical risk of a sharp rise in blood pressure; a review of the published literature found no reported cases of this happening, though the warning remains on the label.
- Many of the trials behind these reasons were small, some with fewer than ten people, and several of the exercise trials tested only men, so how well the findings carry over to other groups is not yet clear.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (14 studies)
- On the effects of tyrosine supplementation on interference control in a randomized, double-blind placebo-control trial. (2018, randomised trial)
- Effects of l-Tyrosine on working memory and inhibitory control are determined by DRD2 genotypes: A randomized controlled trial. (2016, randomised trial)
- Tyrosine promotes cognitive flexibility: evidence from proactive vs. reactive control during task switching performance. (2015, randomised trial)
- Eating to stop: tyrosine supplementation enhances inhibitory control but not response execution. (2014, randomised trial)
- Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill. (2024, randomised trial)
- The catecholamine precursor Tyrosine reduces autonomic arousal and decreases decision thresholds in reinforcement learning and temporal discounting. (2022, randomised trial)
- The effect of tyrosine supplementation on whole-body endurance performance in physically active population: A systematic review and meta-analysis including GRADE qualification. (2023, meta-analysis)
- Effects of L-Tyrosine Ingestion on Endurance Performance in Mentally Fatigued Cyclists. (2026, randomised trial)
- Tyrosine supplementation is ineffective in facilitating soccer players' physical and cognitive performance during high-intensity intermittent exercise in hot conditions. (2025, randomised trial)
- Failure of oral tyrosine supplementation to improve exercise performance in the heat. (2014, randomised trial)
- Food for creativity: tyrosine promotes deep thinking. (2015, randomised trial)
- Tyrosine for Mitigating Stress and Enhancing Performance in Healthy Adult Humans, a Rapid Evidence Assessment of the Literature. (2015, review)
- Administration of supplemental L-tyrosine with phenelzine: a clinical literature review. (2014, review)
- Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review. (2015, review)
How much does L-Tyrosine cost?
That depends on the form and the pack, so we work out the price of the same dose of every L-Tyrosine product we can find and rank them.