Our bodies use amino acids to create the chemicals that allow our nervous systems to function. One of these amino acids is L-tyrosine. Our bodies use it to create the neurotransmitter dopamine. A highly bioavailable form of this amino acid called N-acetyl L-tyrosine (NALT or NAT) has become popular with nootropic users.
In this science-backed article, we’re going to take a look at the nootropic benefits of N-acetyl L-tyrosine. But before we do, let’s see what NALT is and how it works in the body.
What Is N-Acetyl L-Tyrosine (NALT)?
This is a highly bioavailable form of L-Tyrosine, an amino acid the body uses to create the neurotransmitter dopamine. L-tyrosine is what’s known as a precursor. These are substances the body uses to create other substances. By using the enzyme tyrosine hydroxylase, the brain converts L-tyrosine into L-DOPA (levodopa). Then, through a process called decarboxylation, L-DOPA is converted into dopamine.
Dopamine is a neurotransmitter known to play a role in motivation, reward, arousal, executive functions, motor control, and more. Because of this, dopamine is often one of the main neurotransmitters affected by nootropics.
From there, the body uses dopamine to create norepinephrine (noradrenaline) and epinephrine (adrenaline), two other neurotransmitters. Norepinephrine is known to play a role in arousal, alertness, and readiness for action. Together, these three neurotransmitters are collectively known as catecholamines.
Nootropic users have been using both L-tyrosine and N-acetyl L-tyrosine for years to improve cognitive performance. Among the benefits typically reported are those associated with the catecholamines: increased attention, focus, and motivation, and improved overall cognition. We’ll take a look at what the science has to say about these claims shortly. But first, let’s compare L-tyrosine with N-acetyl L-tyrosine.
L-Tyrosine vs N-Acetyl L-Tyrosine (NALT)
N-acetyl L-tyrosine (NALT) is just L-tyrosine with an added acetyl group. In the body, NALT breaks down into L-tyrosine. So why do some nootropic users take NALT instead of regular L-tyrosine?
The main reason is bioavailability. NALT has been shown to be much more soluble than L-tyrosine. Because of this, it’s often assumed that NALT is more bioavailable and thus increases dopamine levels more than regular L-tyrosine. But the science paints a different picture.
A placebo-controlled study published in the Journal of Pharmacy and Pharmacology compared oral administration of several forms of tyrosine. The researchers checked brain tyrosine levels after 1 and 4 hours post-administration. While both L-tyrosine and NALT increased tyrosine levels in the brain, L-tyrosine increased them nearly twice as much at the 1 hour mark. After 4 hours, brain tyrosine levels were slightly higher in the L-tyrosine group than in the NALT group. Both were higher than placebo.
Additionally, a 2003 study showed that 35% of NALT is excreted unchanged in urine. Obviously, if 35% of NALT is excreted, it’s not being converted to L-DOPA and then dopamine. Comparatively, levels of L-tyrosine excreted in urine are around 5%.
In spite of all this, many people report a greater nootropic effect from taking NALT than L-tyrosine. However, some nootropic users report the exact opposite. It appears to come down to individual body chemistry. But as we’ve explored above, there’s no question that both L-tyrosine and NALT can increase catecholamine levels in the brain. Now let’s take a look at the nootropic benefits of NALT and L-tyrosine.
The Nootropic Benefits of L-Tyrosine and N-Acetyl L-Tyrosine (NALT)
Nootropic users have claimed a number of benefits from taking both L-tyrosine and N-acetyl L-tyrosine (NALT). These benefits include improved memory and mood, decreased anxiety and stress, and more. Let’s see what the science has to say about these claims.
A 1989 study took a look at the effect that l-tyrosine had on stressed (but otherwise healthy) humans. This study used a double-blind, placebo-controlled model. The researchers wanted to see how people given l-tyrosine reacted to 4.5 hours of being exposed to cold and hypoxia (lack of oxygen). The participants given l-tyrosine shows significantly less signs of stress than those given a placebo. The tyrosine group has less stress, less performance impairment, and a more stable affect.
A 2015 literature review published in Military Medicine also showed that tyrosine supplementation could reduce cognitive stress. This review looked at the results of 14 previously-published studies. The researchers concluded that while tyrosine supplementation doesn’t reduce physical stress, it may boost cognitive performance by reducing mental stress.
A 1999 placebo-controlled study looked at the effect tyrosine supplementation had on 21 cadets during a military combat training course. The researchers monitored the cadets mood, blood pressure, and stress levels. While they didn’t notice any affect on mood, the researchers found that tyrosine supplementation could reduce blood pressure and the effects of fatigue and stress on cognitive tasks.
The research that’s been done on the effect tyrosine has on mood has been less encouraging. While some research has shown that tyrosine supplementation can improve mood in depressed patients, others have shown no effect.
A 1983 review published in the Journal of Psychiatric Research mentioned a study where at least one depressed patient’s mood improved with tyrosine supplementation. However, other studies have failed to find any effect on mood.
A double-blind, placebo-controlled clinical trial done in 1990 looked at the effect L-tyrosine supplementation had on patients diagnosed with major depressive disorder (MDD). 65 participants were given either L-tyrosine, imipramine (an antidepressant), or placebo for 4 weeks. The participants in the L-tyrosine group did not experience any improvement in mood.
Increased Cognitive Flexibility
This is an interesting one. A 2015 study found that tyrosine supplementation increased cognitive flexibility. This is the ability to switch between thinking about two-or-more concepts at the same time. In this double-blind, randomized, placebo-controlled study, 22 healthy adults performed a number of tests. The researchers found that the participants given L-tyrosine showed greater cognitive flexibility than the participants in the placebo group.
Increased cognitive flexibility definitely sounds like a nootropic benefit to me. Being able to easily switch between multiple concepts at the same time should increase overall productivity.
This is one of the most sought after benefits of nootropic users. Several studies have shown that tyrosine supplementation can improve working memory. Let’s take a look at a couple of them.
A 2006 study published in Physiology & Behavior looked at the effect tyrosine had on cold-related memory deficits. 15 participants completed a battery of tests after being immersed in warm water and then cold water resulting in lowered body temperature. Each participant did one warm and two cold-water tests. During each of the cold-water tests, they were given an energy bar that either contained L-tyrosine or a placebo. The participants performed better on the memory-related tests when given the energy bar containing tyrosine. The researchers concluded that tyrosine supplementation is effective at improving working memory and overall cognitive performance when exposed to cold temperatures.
A similar study published in the same journal the following year had comparable results. 19 healthy volunteers completed three test sessions over the course of multiple days: one after being immersed in warm water (control) and two after cold water. Before the cold water tests, participants were either given L-tyrosine or a placebo. The participants given L-tyrosine showed faster and more accurate information processing. The researchers concluded that tyrosine supplementation improved the working memory deficits caused by cold-water immersion.
A 2013 study published in Frontiers in Behavioral Neuroscience looked at the effect L-tyrosine supplementation had on cognitive functioning. The participants of this study performed an N-back task under demanding and non-demanding conditions. N-back tests are used to measure memory and concentration. The results of this study showed that the participants given L-tyrosine performed better on N-back tasks under demanding conditions.
As you can see, there is quite a bit of research to suggest that tyrosine supplementation can improve memory. These are just a few studies from the past couple decades, but there are others that also support tyrosine’s effectiveness at improving memory. It seems to be especially effective during stressful situations.
Improved Overall Cognition
Some other studies have also shown that tyrosine supplementation can improve various aspects of cognition. Let’s take a look at a couple of them now.
A 2003 study published in Nutritional Neuroscience compared the effects of tyrosine, phentermine, caffeine, amphetamine, or placebo on sleep deprived (but otherwise healthy) young men. A variety of tests were performed by the researchers. Although not as effective as some of the other substances, tyrosine improved performance on several tests. The sleep-deprived participants given L-tyrosine had improved mathematical processing, logical reasoning, and working memory.
A 2015 review published in the Journal of Psychiatric Research looked at a number of human studies done on tyrosine. The researchers state that, while there isn’t a lot of evidence to support tyrosine’s use to improve physical performance, there is lots of evidence to suggest it can improve cognitive performance. However, they note that most of the research done has been on participants who’s dopamine and norepinephrine levels were temporarily depleted by cold or other stressors. So it’s unclear whether or not tyrosine improves cognition in non-impaired individuals.
Lastly, another 2015 review published in Pharmacology, Biochemistry, & Behavior found tyrosine to have a beneficial effect on cognition. This review looked at the results of 15 previously published studies. The authors found that tyrosine supplementation had no significant effect on exercise performance. However, they did find that tyrosine improves working memory and information processing, particularly under demanding situations.
L-Tyrosine and N-Acetyl L-Tyrosine (NALT) Dosage
Since NALT is much more bioavailable than L-tyrosine, lower dosages are needed. Typical NALT dosages used for nootropic purposes range anywhere from 300-1,000 milligrams (mg).
L-tyrosine dosages are usually much higher. In many of the studies mentioned above, dosages of 100-150 mg/kg of body weight were used. For someone who weighs between 150-200 pounds, this comes out to anywhere from 9-13.5 grams (that’s 9,000-13,500 mg). However, some people use L-tyrosine in doses of between 500-2,000 mg.
Most nootropic users prefer NALT to L-tyrosine for its superior bioavailability and comparable effectiveness at much lower dosages. Personally, I’ve tried them both and find the effects to be similar. So I agree with most nootropic users: NALT is the way to go if you’re looking to boost dopamine and norepinephrine levels by using a precursor.
L-Tyrosine and NALT Side Effects
In all the studies we’ve looked at, the researchers did not note any adverse effects other than upset stomach in some participants. Several authors did note how well tyrosine was tolerated. If you experience upset stomach from taking L-tyrosine or NALT, you could try lowering the dosage or taking it with a meal. However, taking either of them with food may decrease absorption.
Where To Buy N-Acetyl L-Tyrosine (NALT)
Most online nootropic vendors offer NALT. Some sell it in capsule form, others as a powder. If it’s NALT capsules you’re looking for, I recommend getting them from Pure Nootropics. They’ve been around for years and are one of the leading online nootropic vendors.
If you’re looking for NALT in powder form, I recommend Nootropics Depot. They offer 125 and 250-gram tubs of NALT powder at a lower price than most of their competitors. Nootropics Depot has an excellent reputation for providing high-quality products and having an amazing selection of nootropic products to choose from. They also offer NALT in capsule form.