N-acetyl-L-tyrosine (NALT) supposedly has better absorption and stronger nootropic effects than L-tyrosine. However, science tells a different story and points to some major drawbacks. Read on to find out if NALT is a better option and how to use it properly.
What is N-Acetyl-L-Tyrosine?
A Form of L-Tyrosine
L-tyrosine is an amino acid your body uses to make proteins, neurotransmitters, and other vital compounds. Your body can make it from another amino acid, phenylalanine. You can also get it from good protein sources such as cheese, meat, eggs, and beans [1, 2, 3].
N-acetyl-L-tyrosine (NALT or NAT) is a derivative of L-tyrosine promoted for its supposedly higher absorption and efficacy. People use it as a supplement to boost their physical and mental performance. Still, science supports only a fraction of these claims and anecdotal benefits.
- Boosts cognition and alertness under stress
- May improve mood
- May increase thyroid hormones
- May speed up metabolism
- Only partly metabolized into L-tyrosine
- May cause headaches and fatigue
- May worsen cognition in the elderly
- Interacts with L-DOPA and thyroid medications
- Not well studied in humans
The potential health benefits discussed below refer to L-tyrosine if not stated otherwise. Although NALT is a source of L-tyrosine, it may not have the same health effects.
How It Works
A portion of ingested NALT turns into L-tyrosine, an amino acid with promising nootropic and stimulant effects. L-tyrosine increases neurotransmitters known as catecholamines: dopamine, norepinephrine, and epinephrine .
They play central roles in your mental health, cognition, behavior, and stress response. The body needs a steady supply of tyrosine to maintain their production and keep physical and cognitive performance at peak levels [5, 6].
Cognition, Memory & Wakefulness
In multiple clinical trials, L-tyrosine was able to boost cognition, alertness, and memory in stressful and demanding situations [7, 8].
It seems to have a nootropic effect in extreme conditions that deplete catecholamines and expose the body to additional stress. These include sleep deprivation, multitasking, military training, and cold weather [9, 10, 11].
Users attribute the same benefits to N-acetyl-L-tyrosine, but studies haven’t confirmed this yet.
No valid clinical evidence supports the use of NALT or L-tyrosine for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.
According to low-quality clinical evidence and animal trials, L-tyrosine may also:
- Increase thyroid hormones [12, 13]
- Help with heroin addiction and withdrawal 
- Speed up metabolism 
- Improve mood [16, 12]
L-tyrosine doesn’t seem to be effective for:
Read this post about the benefits of l-tyrosine.
NALT vs. L-Tyrosine
N-acetyl-tyrosine is more water-soluble than L-tyrosine and thus more suitable for parenteral (intravenous) nutrition for people who can’t eat and drink .
The body supposedly also uses it better from supplementation than L-tyrosine, but the evidence doesn’t fully support these claims. We partly metabolize NALT into free tyrosine but eliminate 35-38% of unchanged substance with the urine [23, 24, 25].
In a study of 13 people, NALT didn’t increase tyrosine levels at all. The authors suggested tyrosine linked to other amino acids (alanine or glycine) as preferred options for parenteral nutrition .
All studies used injected NALT, and there’s no available data on the metabolism and efficacy of oral supplements.
However, acetylation of amino acids is a well-known and powerful tool for boosting their brain uptake and stability, which often unlocks new health benefits. N-acetyl-cysteine (NAC) and acetyl-DL-leucine both have beneficial effects on the brain and mental health [27, 28, 29].
Future research should investigate the potential advantages of the acetylated form of L-tyrosine.
N-Acetyl-L-Tyrosine Side Effects & Safety
Common Side Effects
Keep in mind that the safety profile of NALT is relatively unknown, given the lack of clinical data. Although similar to L-tyrosine, it may have different side effects. Consult your doctor about all potential side effects, based on your health condition and possible drug or supplement interactions.
In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.
L-tyrosine is labeled as “generally recognized as safe” (GRAS) by the FDA. It can cause only minor side effects such as [7, 20, 30]:
NALT gets transformed into L-tyrosine in your body and should thus be safe for oral consumption. However, no clinical trials have verified its long-term safety yet.
In an observational trial of over 3,400 Chinese participants, high blood levels of tyrosine were associated with increased rates of diabetes type 2. The association was much stronger for those who had low HDL, or “good” cholesterol .
Excessive dietary tyrosine increased cholesterol levels in one study on rats .
Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let them know about all drugs and supplements you are using or considering.
L-tyrosine may interact with L-DOPA and thyroid medications [33, 12].
Since some users take NALT for Parkinson’s disease, the potential interaction with L-DOPA deserves attention. As a source of tyrosine, NALT may hinder the transport of L-DOPA into the brain and cause variations in its effectiveness known as the “on-off” phenomenon .
The fact that high doses of L-tyrosine may cause cognitive decline in the elderly questions the use of NALT in this population .
Children and pregnant women should avoid NALT unless prescribed by their doctor.
N-Acetyl-L-Tyrosine Dosage & Supplements
NALT supplements have not been approved by the FDA for medical use. In general, regulatory bodies aren’t assuring the quality, safety, and efficacy of supplements. Speak with your doctor before supplementing.
The below doses may not apply to you personally. If your doctor suggests using NALT, work with them to find the optimal dosage according to your health condition and other factors.
NALT usually comes in 350 mg pills or bulk powders. The second option may be better, given the high dosage of L-tyrosine used in most clinical trials: 7 g daily for a 154-lbs (70-kg) person [7, 20].
That said, product manufacturers suggest much lower NALT doses (700-1000 mg), which seem to be effective in some users.
For short-term nootropic effects, taking it 30-60 mins before a stressful or challenging task may give the best results .
Supplement retailers often make unverified claims about the advantages of NALT over L-tyrosine. As mentioned, L-tyrosine remains a better choice for oral supplementation according to the available evidence.
The opinions expressed in this section are solely from the users who may or may not have medical background. Their reviews do not represent the opinions of SelfHacked. SelfHacked does not endorse any specific product, service, or treatment.
Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or another qualified healthcare provider because of something you have read on SelfHacked.
Users take NALT to boost cognitive performance, mood, and thyroid hormones. The majority of them report positive experiences, while others find it ineffective and inferior to L-tyrosine.
Older patients use it for Parkinson’s disease, and they also report mixed results.
The most common side effects are fatigue and headache.
Where to Buy L Tyrosine
N-acetyl-L-tyrosine (NALT) is a derivative of L-tyrosine, an amino acid that builds neurotransmitters crucial for brain health. It may boost cognition and alertness in stressful situations. There’s insufficient evidence for other purported benefits such as mood improvement, weight loss, and substance withdrawal.
Supplements contain pills with 350 mg of NALT, but a higher dose may be needed for optimal results. Users take 700-1000 mg and report decent nootropic effects. However, some of them have experienced headaches, fatigue, and nausea.
Although NALT is a more soluble form of tyrosine and supposedly has better absorption, studies on oral supplementation are scarce. Until more evidence shows up, you may want to stick with L-tyrosine.
Both forms can interact with certain medications, and they are not suitable for children and pregnant women. Talk to your doctor before supplementing.