supplementNot FDA-approvedOTC supplementN-acetyl-L-tyrosine is sold in the US as a dietary supplement and is not an FDA-approved drugClinical use of the acetylated form has been limited to parenteral nutrition research rather than routine outpatient prescribing
N-Acetyl L-TyrosineBenefits, Dosage & Interactions
Also known as: NALT
N-Acetyl L-Tyrosine (NALT) is an acetylated derivative of the amino acid L-tyrosine. L-tyrosine is a non-essential amino acid that serves as a precursor for several important neurotransmitters, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), collectively known as catecholamines. Research on N-Acetyl L-Tyrosine focuses on cognition and mood.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Moderate — Covered by a systematic review, without regulatory approval.
Evidence strengthModerate · 3/4
PreclinicalStrong human evidence
Covered by a systematic review, without regulatory approval.
Plasma half-life
Not applicable
Typical timing
morning
Food rule
empty stomach
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- N-acetyl-L-tyrosine has been studied as a tyrosine substitute in parenteral nutrition formulas and in oral tyrosine-loading studies reviewed alongside free tyrosine doses of roughly 100–150 mg/kg body weight[1][2][3]
Reported for N-Acetyl L-Tyrosine in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the N-Acetyl L-Tyrosine entry is written from. Each number matches an inline marker above.
- [1]N-acetyl-L-tyrosine as a tyrosine source in adult parenteral nutritionBerlana D, Sabin P, Gimeno-Ballester V, et al. · JPEN. Journal of Parenteral and Enteral Nutrition · 2003 · Peer-reviewed · PMID 14621123
- [2]Utilization of tyrosine dipeptides and acetyltyrosine in normal and uremic humansFurst P, Stehle P · The American Journal of Physiology · 1991 · Peer-reviewed · PMID 1996632
- [3]Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A reviewJongkees BJ, Hommel B, Kuhn S, Colzato LS · Journal of Psychiatric Research · 2015 · Peer-reviewed · PMID 26424423
How to track N-Acetyl L-Tyrosine doses
Tracking N-Acetyl L-Tyrosine well takes four fields and a habit. Here is what to record so the log is still useful in three months.
- 1
Add the dose and unit
Log N-Acetyl L-Tyrosine with its dose in mg so totals stay comparable over time — including days when you split the dose or skip it.
- 2
Set the time of day and food rule
Typical timing is morning. Take it on an empty stomach, and record it that way so absorption stays consistent. Reminders fire at that time and can export to your calendar.
- 3
Check it against the rest of the stack
Run N-Acetyl L-Tyrosine through the interaction checker against everything else in the routine — supplements, peptides, hormones and prescriptions — before it becomes a daily habit.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
Review N-Acetyl L-Tyrosine alongside your logged metrics and any relevant blood work every few weeks before changing the dose, so the change is a response to data rather than to a good or bad day.
What to log each time
- Dose in mg
- Time of day and whether it was taken on an empty stomach
- Taken / skipped / delayed
- Any side effects or notable changes
References & Evidence
Sources on this page that document N-Acetyl L-Tyrosine dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is N-Acetyl L-Tyrosine studied for?
What is N-Acetyl L-Tyrosine?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
N-Acetyl L-Tyrosine (NALT) is an acetylated derivative of the amino acid L-tyrosine. L-tyrosine is a non-essential amino acid that serves as a precursor for several important neurotransmitters, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), collectively known as catecholamines. It is also a precursor to thyroid hormones and melanin pigment (PubChem). The acetylation of L-tyrosine to form NALT is thought by some manufacturers to enhance its bioavailability compared to standard L-tyrosine; however, scientific evidence directly comparing the absorption and efficacy of NALT versus L-tyrosine in humans is not consistently robust. Some research suggests NALT may have better water solubility (Examine.com), which theoretically could improve absorption. However, other studies indicate that NALT may actually be less efficiently converted to tyrosine in the body compared to L-tyrosine itself (Examine.com). Regardless of conversion efficiency, the ultimate goal of NALT supplementation is to supply the body with L-tyrosine, which can then be utilized in the synthesis of catecholamines. These neurotransmitters play key roles in mood, stress response, and cognitive functions such as alertness, attention, and executive function. NALT is commonly used as a dietary supplement marketed for cognitive enhancement, stress reduction, and support during physically or mentally demanding situations.
What does the research say about N-Acetyl L-Tyrosine?
Tap a section to expand.
The primary mechanism of action for N-Acetyl L-Tyrosine (NALT) is its role as a precursor to the amino acid L-tyrosine. Once absorbed and, if necessary, deacetylated back to L-tyrosine in the body, it enters the metabolic pathway for catecholamine synthesis. The synthesis process begins with L-tyrosine being converted to L-DOPA (L-3,4-dihydroxyphenylalanine) by the enzyme tyrosine hydroxylase (TH). This is the rate-limiting step in catecholamine synthesis (NCBI Bookshelf). Subsequently, L-DOPA is decarboxylated to dopamine by DOPA decarboxylase. Dopamine can then be converted to norepinephrine by dopamine beta-hydroxylase. Finally, norepinephrine can be methylated to epinephrine by phenylethanolamine N-methyltransferase (Examine.com, PubChem).
Catecholamines are neurotransmitters that govern a wide range of physiological responses. Dopamine is crucial for reward, motivation, motor control, and executive functions. Norepinephrine is involved in alertness, arousal, vigilance, and the 'fight-or-flight' stress response. Epinephrine also plays a significant role in the stress response, increasing heart rate, muscle strength, blood pressure, and sugar metabolism (MedlinePlus). By increasing the availability of L-tyrosine, NALT aims to support the synthesis of these neurotransmitters. This mechanism is particularly relevant when the demand for catecholamines is high, such as during acute stress, sleep deprivation, or demanding cognitive tasks, where endogenous L-tyrosine levels might be depleted (Cochrane review). The brain's ability to synthesize catecholamines is highly dependent on L-tyrosine availability. Therefore, providing additional L-tyrosine (via NALT) may help to maintain or restore optimal neurotransmitter levels under specific challenging conditions.
Source for this section: Sources for How does N-Acetyl L-Tyrosine work?: Jumps to this entry in the sources and references list at the end of the page.
NALT is primarily explored for its potential benefits related to cognitive function and stress response, largely due to its role as a precursor to catecholamine neurotransmitters.
* **Cognitive Function Under Stress:** Research, including some Cochrane reviews, has investigated L-tyrosine (and by extension NALT) for its ability to mitigate cognitive decline during acute stress, sleep deprivation, or demanding tasks. Studies suggest that under conditions of acute stress (e.g., cold exposure, noise, combat simulation, prolonged wakefulness), L-tyrosine supplementation may help maintain working memory, attention, reaction time, and vigilance by preventing the depletion of catecholamines (Cochrane Review, _Nutrients_ journal review). This effect is generally not observed in unstressed individuals.
* **Mood Regulation:** As a precursor to dopamine and norepinephrine, NALT may indirectly influence mood. While not a direct antidepressant, some individuals report perceived improvements in mood or a reduction in feelings of being 'run down' when facing chronic stressors, possibly by supporting neurotransmitter balance (Examine.com).
* **Enhanced Alertness and Focus:** By potentially supporting optimal levels of norepinephrine and dopamine, NALT is sometimes used to enhance alertness and focus, particularly during periods of mental fatigue or low motivation. This aligns with its role in the catecholamine synthesis pathway, which is critical for arousal and attention (Examine.com). However, robust clinical evidence specifically for NALT (rather than L-tyrosine) demonstrating these effects in healthy, unstressed individuals is limited.
* **Support During Physical Demands:** Athletes and individuals undergoing intense physical training sometimes use NALT, hypothesizing it could aid in maintaining mental acuity and reducing perceived effort during strenuous activity by sustaining catecholamine levels (Examine.com). The evidence supporting this directly in performance is less clear than for cognitive function under stress.
The evidence for N-Acetyl L-Tyrosine largely mirrors that of L-tyrosine, as NALT's primary function is to deliver L-tyrosine to the body. Most research focuses on L-tyrosine:
* **Cognitive Performance Under Stress:** A significant body of evidence, including meta-analyses and systematic reviews, supports L-tyrosine's role in preserving cognitive function under conditions of acute stress (e.g., cold, high altitude, combat scenarios, sleep deprivation). A Cochrane review noted that several studies have shown L-tyrosine can improve performance on tasks related to working memory and attention when individuals are exposed to stressful environments or sleep deprivation. However, it emphasized that these effects are not typically observed in healthy, unstressed individuals (_Nutrients_ journal, Cochrane Library).
* **Bioavailability:** The claim that NALT is more bioavailable than L-tyrosine is not consistently supported by robust human data. Some animal and in-vitro studies suggest improved solubility for NALT, but human pharmacokinetic studies have yielded mixed results regarding its conversion efficiency to L-tyrosine in the body (Examine.com). Some research indicates that NALT may actually be a less efficient delivery method for L-tyrosine than L-tyrosine itself (DrugBank, Examine.com). More direct comparative research in humans is needed.
* **Mood and Alertness:** While the theoretical basis linking L-tyrosine to mood and alertness via catecholamine synthesis is sound, direct clinical trials specifically showing NALT's efficacy for these outcomes in healthy individuals (not under stress) are less conclusive or plentiful. Effects, if any, are generally subtle and more likely to be present during periods of increased demand on the catecholamine system.
* **Dosage considerations for L-Tyrosine studies:** Studies commonly use L-tyrosine in doses ranging from 500 mg to 2000 mg, sometimes higher, especially in acute stress protocols. Individual needs vary — talk to a licensed clinician.
Overall, the strongest evidence for NALT (and L-tyrosine) pertains to its potential benefit in maintaining cognitive performance and mood under acute stressful conditions where catecholamine depletion is likely to occur.
N-Acetyl L-Tyrosine (NALT) is generally considered well-tolerated when consumed at commonly studied doses (Examine.com). However, as with any supplement, potential side effects can occur. These are often mild and may include:
* Gastrointestinal upset, such as nausea, heartburn, or stomach discomfort.
* Headaches.
* Fatigue, paradoxically, in some individuals.
* Jitteriness or anxiety, particularly if taken in very high doses or combined with other stimulants.
More severe side effects are rare but can include allergic reactions. Individuals with pre-existing conditions or those taking other medications should exercise caution and consult a healthcare professional. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Individuals with certain medical conditions should approach N-Acetyl L-Tyrosine (NALT) with caution. Because NALT is a precursor to thyroid hormones, individuals with hyperthyroidism (overactive thyroid) or Graves' disease should avoid NALT or use it only under strict medical supervision, as it could potentially exacerbate their condition (Examine.com). Similarly, those with melanoma, a type of skin cancer, should consult a clinician, as tyrosine is a precursor to melanin pigment and there is a theoretical concern about stimulating cancer growth, though this is not well-established in clinical practice. Individuals with phenylketonuria (PKU) should also exercise extreme caution as their bodies cannot properly metabolize phenylalanine and tyrosine, and supplementation could be problematic (MedlinePlus). Pregnant or breastfeeding individuals should avoid NALT due to a lack of sufficient safety data. As NALT can affect neurotransmitter levels, individuals with mental health conditions, especially those prone to anxiety or manic episodes, should use it only under medical guidance. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
N-Acetyl L-Tyrosine (NALT) is contraindicated in individuals with certain medical conditions to prevent adverse health outcomes. Absolute contraindications include:
* **Hyperthyroidism:** NALT is a precursor to thyroid hormones. Supplementation could lead to an overproduction of these hormones, worsening symptoms in individuals with an already overactive thyroid (Examine.com).
* **Graves' Disease:** Similar to hyperthyroidism, this autoimmune condition can be exacerbated by increased substrate for thyroid hormone production (Examine.com).
* **Phenylketonuria (PKU):** Individuals with PKU have a genetic inability to properly metabolize phenylalanine, which can lead to a buildup of toxic byproducts and impaired tyrosine production. While tyrosine is typically deficient in PKU, supplementation should be done under strict medical guidance due to the complex metabolic interactions (MedlinePlus). Over-supplementation could potentially disrupt the delicate balance maintained through dietary restrictions.
* **Melanoma:** While theoretical, there's a concern (not definitively proven) that tyrosine, a precursor to melanin, could potentially stimulate the growth of melanoma (PubChem). Therefore, it is generally advised against use.
Relative contraindications or situations requiring strict medical supervision include pregnancy, breastfeeding, and individuals with a history of bipolar disorder or other mental health conditions where mood swings or manic episodes could theoretically be influenced by changes in catecholamine levels. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Caution should be exercised when combining N-Acetyl L-Tyrosine (NALT) with certain medications or other supplements due to potential interactions or additive effects.
* **Thyroid Hormones:** Since NALT is a precursor to thyroid hormones, taking it concurrently with synthetic thyroid hormones (e.g., levothyroxine) could potentially lead to an oversupply of thyroid hormones in the body, which could be dangerous for individuals with hypothyroidism or those undergoing thyroid hormone replacement therapy. This could also interfere with the proper dosing of such medications (Examine.com).
* **MAO Inhibitors (MAOIs):** Monoamine oxidase inhibitors are a class of antidepressants that block the breakdown of monoamine neurotransmitters, including dopamine, norepinephrine, and serotonin. Combining NALT, which increases the availability of catecholamine precursors, with MAOIs could theoretically lead to dangerously high levels of these neurotransmitters, potentially causing a 'hypertensive crisis' with symptoms like severe headache, chest pain, and rapid heartbeat (DrugBank). This combination is generally contraindicated.
* **Stimulant Medications:** NALT may have an additive effect when combined with stimulant medications such as those for ADHD (e.g., methylphenidate, amphetamines) or other adrenergic drugs. This could increase the risk of side effects like increased heart rate, blood pressure, anxiety, or jitteriness (Examine.com).
* **Other Catecholamine Precursors:** Combining NALT with other supplements that increase dopamine or norepinephrine, such as L-DOPA (Mucuna pruriens), could potentially lead to excessive neurotransmitter levels.
Always consult a healthcare professional before combining NALT with any other medications or supplements. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
N-Acetyl L-Tyrosine (NALT) is typically recommended for intake in the morning or early afternoon, particularly if its purpose is to support alertness or focus. Taking it later in the evening might interfere with sleep for some individuals due to its potential stimulating effects on catecholamine neurotransmitters (Examine.com). It is often suggested to take NALT on an empty stomach, approximately 30-60 minutes before a meal, to potentially enhance absorption, as amino acid absorption can be competitive with other food components (Examine.com). However, if gastrointestinal upset occurs, taking it with a light snack might be tolerated better. For acute stress or cognitive demands, some individuals may take it approximately 30-60 minutes before the stressful event or demanding task.
Source for this section: Sources for When should you take N-Acetyl L-Tyrosine?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with N-Acetyl L-Tyrosine?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any glp1 + supplement | Note | Category ruleConfidence: theoretical | GLP-1 medications slow stomach emptying, changing how/when oral supplements absorb; rapid weight loss raises the importance of protein and micronutrients.Source pending | Time oral supplements when nausea is lowest; prioritize protein and micronutrients; discuss with your provider. |
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pending | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
Frequently asked questions about N-Acetyl L-Tyrosine
N-Acetyl L-Tyrosine is a supplement. It is also known as NALT. What follows is drawn from peer-reviewed literature indexed on PubMed, FDA label text where a label exists, and NIH reference records.
N-Acetyl L-Tyrosine is commonly discussed in the context of supporting brain. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For N-Acetyl L-Tyrosine, it is typically taken in the morning and it is usually taken on an empty stomach. Always follow the specific dose your clinician or the product label prescribes.
N-Acetyl L-Tyrosine carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
N-Acetyl L-Tyrosine is a supplement, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Because N-Acetyl L-Tyrosine is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers N-Acetyl L-Tyrosine with no sign-up.
Combining a supplement like N-Acetyl L-Tyrosine with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Each peptide class carries its own profile against N-Acetyl L-Tyrosine: a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for N-Acetyl L-Tyrosine varies by protocol and formulation, so the label or prescription is what sets it. It is typically taken in the morning. Most protocols have it taken on an empty stomach. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of N-Acetyl L-Tyrosine depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For N-Acetyl L-Tyrosine the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at N-Acetyl L-Tyrosine?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Utilization of tyrosine-containing dipeptides and N-acetyl-tyrosine in hepatic failure(opens PubMed in a new tab)Hepatology · 1995 · PMID 7705801 · https://pubmed.ncbi.nlm.nih.gov/7705801/
- 2.Amino acid solutions for premature neonates during the first week of life: the role of N-acetyl-L-cysteine and N-acetyl-L-tyrosine(opens PubMed in a new tab)JPEN J Parenter Enteral Nutr · 1994 · PMID 7815670 · https://pubmed.ncbi.nlm.nih.gov/7815670/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 68310(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/68310
Verify at
Publisher search links for N-Acetyl L-Tyrosine. These are places to check the information — they are not citations, so they are not numbered.
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Examine.com(publisher search, opens in a new tab)Examine.com · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed labeling archive(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on N-Acetyl L-Tyrosine?
Plain-text summary, safe to quote verbatim:
N-Acetyl L-Tyrosine (NALT) is an acetylated derivative of the amino acid L-tyrosine. L-tyrosine is a non-essential amino acid that serves as a precursor for several important neurotransmitters, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), collectively known as catecholamines. Research on N-Acetyl L-Tyrosine focuses on cognition and mood.
Source: DoseRoutine — https://doseroutine.com/library/n-acetyl-l-tyrosine
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). N-Acetyl L-Tyrosine — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/n-acetyl-l-tyrosine
What compounds are similar to N-Acetyl L-Tyrosine?
Others in the supplement category or studied for the same goals.
Which goals is N-Acetyl L-Tyrosine used for?
Other compounds studied for the same benefits as N-Acetyl L-Tyrosine.
Continue exploring
See every compound DoseRoutine catalogs for these goals.