N-Acetyl-L-Tyrosine

Acetylated form of L-tyrosine, marketed nootropic supplement

ATC code: A16AA-NALT (N-Acetyl-L-Tyrosine)

Brand names – supplements

NOW Foods NALT N-Acetyl Tyrosine, Doctor's Best N-Acetyl L-Tyrosine, Jarrow Formulas N-Acetyl Tyrosine

Supplements are not tested in clinical trials and are not registered as medications.

Mechanism of action

Acetylated form of L-tyrosine. iHerb and Amazon sellers position NALT as a more bioavailable version of tyrosine because of better solubility. In practice bioavailability alone does not equal clinical effect: NALT must first be deacetylated to tyrosine to enter the brain, and conversion efficiency in humans is low. There are no head-to-head RCTs of NALT vs L-tyrosine on cognitive tests or clinical outcomes.

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Memory and concentration enhancement

Not recommended

N-acetyl-L-tyrosine (NALT) is marketed as a nootropic for memory, concentration and cognitive endurance. did not confirm the health claim for L-tyrosine in 2011, and the N-acetyl derivative has no separate assessment. There are no RCTs comparing NALT with placebo or with L-tyrosine on cognitive outcomes in humans. Biologically NALT must be deacetylated to tyrosine before entering the brain, and conversion efficiency in humans is low, so the marketing claim of better bioavailability is not supported. If memory bothers the patient, start with sleep hygiene, ferritin, B12 and thyroid checks and discuss the request with a doctor before spending money on NALT.

Sources

EFSA: Scientific Opinion on the substantiation of health claims related to L-tyrosine and contribution to normal synthesis of catecholamines (2011)

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Safety

Contraindications

Hypersensitivity to NALT or L-tyrosine
Hyperthyroidism and thyrotoxicosis
Non-selective MAO inhibitors
Melanoma
Phaeochromocytoma

Serious adverse effects

Hypertensive crisis with non-selective MAO inhibitors
Worsening of thyrotoxicosis
Allergic reactions

Common adverse effects

Nausea
Headache
Insomnia with evening dosing
Palpitations

PregnancyFDA C

FDA Category C. Safety of NALT in pregnancy has not been studied separately. Safety is extrapolated from L-tyrosine: safe in food-derived amounts, with no evaluation of pharmacological doses in pregnant women.

Breastfeeding

Compatible with caution. No data in lactating women; safety is extrapolated from L-tyrosine, which transfers into milk at physiological concentrations.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is N-Acetyl-L-Tyrosine used for?

N-Acetyl-L-Tyrosine is evaluated for the following indications with varying evidence strength: Memory and concentration enhancement (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of N-Acetyl-L-Tyrosine?

Common side effects of N-Acetyl-L-Tyrosine (≥ 1 in 100): Nausea, Headache, Insomnia with evening dosing, Palpitations. See the Safety section for uncommon and serious reactions.

Is N-Acetyl-L-Tyrosine safe during pregnancy?

FDA category C. FDA Category C. Safety of NALT in pregnancy has not been studied separately. Safety is extrapolated from L-tyrosine: safe in food-derived amounts, with no evaluation of pharmacological doses in pregnant women.

Is N-Acetyl-L-Tyrosine compatible with breastfeeding?

Compatible with caution. No data in lactating women; safety is extrapolated from L-tyrosine, which transfers into milk at physiological concentrations.

Who should not take N-Acetyl-L-Tyrosine?

N-Acetyl-L-Tyrosine is contraindicated in: Hypersensitivity to NALT or L-tyrosine; Hyperthyroidism and thyrotoxicosis; Non-selective MAO inhibitors; Melanoma; Phaeochromocytoma. Full list in the Safety section.

Mechanism of action

Safety

Contraindications

Hypersensitivity to NALT or L-tyrosine
Hyperthyroidism and thyrotoxicosis
Non-selective MAO inhibitors
Melanoma
Phaeochromocytoma

Serious adverse effects

Hypertensive crisis with non-selective MAO inhibitors
Worsening of thyrotoxicosis
Allergic reactions

Common adverse effects

Nausea
Headache
Insomnia with evening dosing
Palpitations

PregnancyFDA C

Breastfeeding

Compatible with caution. No data in lactating women; safety is extrapolated from L-tyrosine, which transfers into milk at physiological concentrations.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is N-Acetyl-L-Tyrosine used for?

What are the side effects of N-Acetyl-L-Tyrosine?

Common side effects of N-Acetyl-L-Tyrosine (≥ 1 in 100): Nausea, Headache, Insomnia with evening dosing, Palpitations. See the Safety section for uncommon and serious reactions.

Is N-Acetyl-L-Tyrosine safe during pregnancy?

Is N-Acetyl-L-Tyrosine compatible with breastfeeding?

Compatible with caution. No data in lactating women; safety is extrapolated from L-tyrosine, which transfers into milk at physiological concentrations.

Who should not take N-Acetyl-L-Tyrosine?