Guide
How much L-tyrosine should you take a day?
There's no official recommended dose for L-tyrosine. The trials that found a cognitive effect used single loading doses of 100-150 mg per kilogram of body weight — several times more than the 500 mg to 2 g found on most commercial labels.
There's no official recommended dose of L-tyrosine, unlike vitamins and minerals with a government-set intake range. What exists instead is a gap between what's commonly sold — usually 500 mg to 2 g per serving — and what the trials that found a short-term cognitive effect actually used: single loading doses of 100 to 150 mg per kilogram of body weight, which works out to roughly 7 to 10.5 grams for a 70 kg (154 lb) adult.
What trials have actually tested
Most of the research behind tyrosine's cognitive-performance findings used a single, weight-based loading dose rather than a fixed number of milligrams. A 1994 trial used 100 mg/kg (about 7 g for a 70 kg adult) about an hour before a stress-sensitive cognitive task (PMID 8293316), and a 1989 trial used the same 100 mg/kg dose ahead of a multi-hour cold-and-altitude stress exposure (PMID 2736402). A 1995 trial used a higher amount, 150 mg/kg (about 10.5 g for a 70 kg adult), split into parts and given partway through a night of sleep loss (PMID 7794222). See L-tyrosine benefits: what the research does and doesn't show for what each of these trials actually found.
One field trial used an amount much closer to what's sold commercially: 2 g a day, given daily for 5 days to military cadets during a combat training course, rather than as a single dose timed before one stressful event (PMID 10230711). That's the closest match in this literature to a typical bottle's serving size — most other positive findings came from doses several times higher, taken once, shortly before a specific demanding task.
Why the gap matters
A commercial serving of 500 mg to 2 g is a fraction of the 7-10.5 g single doses used in most of the positive cognitive-performance trials above. That doesn't mean a smaller amount does nothing — no trial has directly tested and compared a 500 mg dose against a 5,000 mg dose head-to-head — but it does mean the label amount on most bottles hasn't itself been the dose tested in the research people are often pointed to. Tyrosine also has to compete with other amino acids for transport into the brain, so how much of a given dose actually reaches the brain depends partly on what else is circulating in the blood at the time, not the milligram number alone (PMID 17513421). See when is the best time to take L-tyrosine? for how that plays into timing.
Is there a maximum, or a dose that's "too much"?
Tyrosine doesn't have an established upper intake level the way magnesium or vitamin D do — no government body has set one specifically for supplemental tyrosine. The highest amount used in the trials reviewed here was 150 mg/kg (about 10.5 g for a 70 kg adult) as a single dose, described by its authors as relatively benign at that level in the people studied (PMID 7794222). That's a description of tolerability in one trial, not a ceiling that's been formally tested as a maximum — going meaningfully beyond it isn't something the research here can speak to either way.
N-acetyl-L-tyrosine (NALT) doses aren't interchangeable with L-tyrosine
Because NALT converts back to usable tyrosine inefficiently in the limited research available (see what is L-tyrosine? A plain guide), a milligram amount of NALT on a label isn't equivalent to the same milligram amount of plain L-tyrosine used in the trials above. No dosing research establishes a reliable conversion between the two forms.
Questions people ask
How much L-tyrosine per day is typical?
Commercial products commonly list 500 mg to 2 g per serving. That range is closer to the 2 g/day used in the one field trial covered above (PMID 10230711) than to the single, larger loading doses used in most of the other cognitive-performance trials.
How much L-tyrosine should I take?
There's no single research-backed number to give. Following the directions on whatever product you're using, and asking a pharmacist if you're unsure — especially if you take any prescription medication — is more reliable than picking a number from this research, since most of it used doses well above a typical serving.
Is 1,000 mg (1 g) of L-tyrosine too much?
No formal maximum exists to compare it against, and 1 g sits below every dose used in the trials reviewed here. It's a common commercial serving size, not an amount flagged as excessive in this research.
How much L-tyrosine to take with a stimulant medication?
This page doesn't cover dosing alongside a specific prescription medication — see L-tyrosine and medications: what to check and ask a doctor or pharmacist before combining the two.
Is there an L-tyrosine dosage calculator?
Not one backed by this research. The trials that found an effect used a dose scaled to body weight (100-150 mg/kg), but none of them compared different doses against each other to identify an optimal amount, so there's no formula to recommend beyond following a product's own label.
What's the dose for N-acetyl-L-tyrosine (NALT)?
No dedicated dosing trial establishes an equivalent NALT amount to the L-tyrosine doses covered above. See what is L-tyrosine? A plain guide for why the two forms aren't interchangeable milligram-for-milligram.
Related reading: what is L-tyrosine? A plain guide, when is the best time to take L-tyrosine?, and L-tyrosine side effects.
Sources
- Effect of tyrosine on cognitive function and blood pressure under stress A 1994 crossover trial in 16 healthy adults found a single 100 mg/kg dose of tyrosine improved performance on two stress-sensitive cognitive tasks under noise stress, with a brief, early dip in diastolic blood pressure and no effect on mood, systolic blood pressure or heart rate.
- Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans A 1989 crossover trial found 100 mg/kg of tyrosine reduced symptoms, adverse mood and performance impairment during a 4.5-hour combined cold-and-high-altitude stress exposure, in people who responded most to that stress.
- The effects of tyrosine on cognitive performance during extended wakefulness A 1995 trial found that 150 mg/kg of tyrosine, given partway through a night of sleep loss, reduced the usual decline in psychomotor performance and vigilance lapses for about 3 hours compared with placebo, and was well tolerated at that dose.
- Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course A 1999 field trial gave 21 military cadets either 2 g/day of tyrosine or a calorie-matched carbohydrate drink for 5 days during a combat training course; the tyrosine group performed better on memory and tracking tasks and had lower systolic blood pressure, with no difference in mood.
- Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain A 2007 review explains that tyrosine is the metabolic precursor of the catecholamine neurotransmitters dopamine, norepinephrine and epinephrine, with the effect concentrated in neurons that are actively firing — a proposed mechanism, not a measurement of what a supplement does in a person.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.