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 really 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 under stress
- Improves milder mood disorders
- May boost thyroid hormones
- Helps with narcolepsy
- Only one part is turned into L-tyrosine
- May cause headaches and fatigue
- May worsen cognition in the elderly
- Interacts with L-DOPA and thyroid medications
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. Your body needs a steady supply of tyrosine to maintain their production and keep your physical and cognitive performance at peak levels [5, 6].
May Boost Cognition, Mood & Wakefulness
In clinical trials, L-tyrosine was able to:
- Boost cognition in stressful and demanding situations [7, 8]
- Help with milder forms of depression and mood disorders [9, 10, 11]
- Combat narcolepsy (daytime sleepiness) [12, 13]
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 [14, 15, 16].
Users attribute the same benefits to N-acetyl-L-tyrosine, but studies have yet to confirm this.
May Increase Thyroid Hormones & Improve Attention
According to limited clinical evidence and animal trials, L-tyrosine may also:
- Increase thyroid hormones [17, 18]
- Help with attention disorders in adults [19, 20]
- Relieve addiction and substance withdrawal 
Effects on Blood Lipids & Weight Loss
In computer tests, several N-acetyl-tyrosine derivatives activated PPAR-alpha, a protein that breaks down fat, boosts weight loss, and increases MTHFR gene production. However, we can’t know if NALT activates the same pathways in humans based on this study .
Benefits Lacking Evidence
There’s not enough evidence to support supplementation for:
- Enhancing physical performance [7, 26]
- ADHD in children 
- Major depression 
- Weight loss 
- Phenylketonuria (PKU) 
- Parkinson’s disease 
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 supplement 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 [32, 33, 34].
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 [36, 37, 38].
Future research may reveal some hidden perks of the acetylated form of L-tyrosine, too.
N-Acetyl-L-Tyrosine Side Effects & Safety
Common Side Effects
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.
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 .
Given these potential drug interactions, make sure to consult your doctor before taking NALT for Parkinson’s or combining it with any medications.
The fact that high doses of L-tyrosine may cause cognitive decline in the elderly also 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
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, you should take it 30-60 mins before a stressful or challenging task .
Note: 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.
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.
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N-acetyl-L-tyrosine (NALT) is a derivative of L-tyrosine, an amino acid that builds neurotransmitters crucial for brain health. It can boost cognition under stress, improve mood, and reduce daytime sleepiness.
Supplements contain pills with 350 mg of NALT, but you may need a higher dosage 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 that supposedly has better absorption, studies on oral supplementation are scarce. Until more evidence shows up, you may want to stick with L-tyrosine.