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Home Nutrition Complete Guide to L-Tyrosine - Benefits, Indications, Proof

Complete Guide to L-Tyrosine – Benefits, Indications, Proof

Based on the research done so far, there is promising evidence that suggests supplementing with tyrosine realigns these important neurotransmitters and improves overall mental function, compared to the results with placebo supplementation.

What is L-Tyrosine and What Does it Do?

L-Tyrosine is essentially an amino acid, commonly found in the diet that is metabolized to produce catecholamines, and that generates noradrenaline and dopamine. It has proved to be helpful in reducing stress in situations when acute stressors go off. Acute stressors tend to consume noradrenaline. It can also be beneficial to people who suffer from stress-induced memory and attention deficits.L-Tyrosine plays also a part in the production of thyroid hormones. Weight loss and pre-workout dietary supplements usually include it for these reasons.

Which foods contain L-Tyrosine?

It can also be found in many foods, the most in cheese, where it was first discovered. Interestingly, “tyros” means “cheese” in Greek.
Food that also contains it is chicken, turkey, fish, dairy products, and a variety of other high-protein foods.

In a nutshell, L-Tyrosine is an amino acid that our body produces with the help of phenylalanine. When used as a supplement, it is believed to help increase important brain chemicals that affect your mood and stress response.

L-TyrosineWhat Are The Benefits of L-Tyrosine?

A lot of people believe that L-Tyrosine can even help with increasing dopamine and adrenaline outright, but this has turned out to be false. The synthesis of catecholamines is very well coordinated in the body, so just increasing the amount of L-tyrosine in your body doesn’t really mean it will increase the overall catecholamine production.

However, there is some evidence that proves that when you are in a stressful situation and noradrenaline expands a protective effect, taking L-Tyrosine supplements seems to provide a ‘safety shield’ of building blocks. This means that it can extend the anti-stress effect of catecholamines by delaying their exhaustion. This has been tested when people experienced cold stress, psychological stress, and sleep deprivation but at a tad higher dose of 150mg/kg. Some researchers claim that this supplement can lead to the improvement in memory and attention during stressful situations, although this effect still isn’t completely trustworthy.

Another potential benefit of using L-Tyrosine supplements could be helping those who are sleep deprived. In one clinical trial done by Aviat Space Environ Med. a single dose of the supplement helped people who didn’t sleep the previous night stay alert for three hours longer than they would otherwise.

To summarize, although studies have shown that L-Tyrosine can help maintain your mental capacity before a stressful situation, there is still no evidence that supplementing with it can boost your overall memory.

Are There Any Side Effects of Taking L-Tyrosine?

L-Tyrosine has so far proven to be safe when taken orally in food amounts and when taken by adults in medicinal amounts over a shorter period of time. L-Tyrosine is most commonly prescribed in doses up to 150 mg/kg per day for about 3 months.

Some of the possible side effects that have been reported so far include nausea, headache, fatigue, heartburn, or joint pain. So far, it hasn’t been thoroughly tested to see if L-Tyrosine is safe for children to use for medical purposes. So remember not to give it to your child unless your doctor advises you to, and until more research has been done.
Generally, L-Tyrosine is considered safe. It’s in the group of basic amino acids that generate proteins in the human body. Although this doesn’t suggest that any amount is safe, it does suggest that the body can handle it safely.

L-Tyrosine before exerciseWhat’s The Best Way to Take L-Tyrosine?

So far, the best way to take L-Tyrosine has been proven to be in doses of 500-2000mg approximately 30-60 minutes before an expected acute stressor.
Studies done by Catherine O’Brian and other researchers have shown the most anti-stress promise for supplemental L-Tyrosine recommend a dosage range of 100-150mg/kg bodyweight which should be taken 60 minutes before exercise, even though it still hasn’t been proven to be beneficial for exercise performances. For example, this is a dosage range of 9-13.5g for a 200lb person and 7-10g for a 150lb person.

If someone is using higher doses and is experiencing digestive issues, it should be split into two separate doses, taken by half an hour (30 and 60 minutes prior to acute stress).

Can L-Tyrosine Help With Working Memory?

Stress is something that a great number of people deal with, it can negatively affect your reasoning, memory, attention, and knowledge by decreasing neurotransmitters.
In one study in 22 women, L-Tyrosine has shown to have a great improvement on working memory during a mentally demanding task, unlike placebo. Working memory is very significant when it comes to concentration and following instructions.

There was one more similar study where 22 participants were given either a tyrosine supplement or placebo before they had to do a test meant to measure cognitive flexibility. Compared to the placebo, L-Tyrosine had a very strong impact on improving cognitive flexibility.

Cognitive flexibility is ones’ ability to quickly switch between tasks or thoughts. The quicker a person can do this, the better their cognitive flexibility.
Keep in mind, L-Tyrosine still hasn’t shown the ability to actually improve memory. The reason for this is that most research doesn’t examine this, and the research that did had mixed results.

Can L-Tyrosine Help With Blood Pressure?

Early research that has been done so far doesn’t suggest that taking tyrosine by mouth affects blood pressure in patients with slightly high blood pressure.
Although, L-Tyrosine has shown promise in reducing blood pressure increases during psychological stress, but not enough research has been conducted on this subject. When it comes to other forms of stress like hypertension, and healthy participants, not many improvements have been registered.

Can L-Tyrosine Help With Depression?

The evidence regarding the effect of L-Tyrosine on depression is still very mixed. Depression is widely believed to occur when the neurotransmitters become unbalanced in your brain. Antidepressants are the most common medication people use to realign these neurotransmitters.

Because tyrosine can help with the production of neurotransmitters, it’s believed that it can also act as some form of an antidepressant. However, experts that have conducted some early research don’t believe this to be true.

There was a study where 65 people with depression received either 100 mg/kg of tyrosine, 2.5 mg/kg of a common antidepressant, or a placebo each day for four weeks. The result of this was that L-Tyrosine didn’t show much promise to have antidepressant effects.
Since depression is such a complex illness, it isn’t that easy to determine whether a food supplement like L-Tyrosine can be useful at dealing with its symptoms.

However, depressed people that have low levels of dopamine, adrenaline, or noradrenaline could potentially benefit from L-Tyrosine.
There was a promising study that tested individuals who had dopamine-deficient depression, and the results suggest that L-tyrosine provided clinically significant benefits.

Can L-Tyrosine Help With Exercise Performance?

So far, the research done on L-tyrosine’s effects on exercise performance has resulted in mixed results. In a 2011 study from the European Journal of Applied Physiology, researchers tested eight healthy male volunteers. They have found that consumption of an L-Tyrosine drink helped increase their endurance while exercising.

However, there have also been studies, like the one in 2016 published in the International Journal of Sports Nutrition and Exercise Metabolism that suggest there is no real influence of L-Tyrosine on those who have taken it before their exercise performance. Participants took L-tyrosine before participating in treadmill walking with a load carriage and it didn’t seem to enhance their strength or endurance. Also, they took L-Tyrosine during a cycling test and it didn’t seem to improve heart rate or performance.

Can L-Tyrosine Help With Phenylketonuria?

Phenylketonuria (PKU) is a very rare genetic illness that is caused by a defect in the gene that helps create the enzyme phenylalanine hydroxylase. Your body uses this enzyme to convert phenylalanine into tyrosine that is later used to create neurotransmitters.
Supplementing with L-Tyrosine could be an option for alleviating the symptoms of this disease, but the evidence so far is mixed.

In one study, experts investigated the effects of tyrosine supplementation alongside or in place of a phenylalanine-restricted diet based on intelligence, growth, nutritional status, mortality rates, and quality of life. The experts analyzed two studies including 47 people but haven’t found a significant difference between those who were supplemented with L-Tyrosine and those with placebo.

Conclusion

In summary, L-Tyrosine is a very popular dietary supplement and it is prescribed for several different reasons.

In the human body, it’s used to create neurotransmitters, which tend to decrease in number when an individual is in a stressful or mentally demanding situation.
Based on the research done so far, there is promising evidence that suggests supplementing with tyrosine realigns these important neurotransmitters and improves overall mental function, compared to the results with placebo supplementation.

Supplementing with L-Tyrosine has been proved to be safe in the research so far, even in high doses. However, it has the potential to negatively react with certain medications, and therefore doctor consultation is recommended before taking it.

While L-tyrosine could potentially have a lot of benefits, more evidence is needed to completely prove its efficiency.

Allison King
The reason why we have entrusted our medical advice to our very own Allison King is her PhD in Biology. Alison has spend her formative years specializing in cell and molecular biology and she also holds an undergraduate degree in biochemistry with a minor in experimental physics. Her experience extends to multiple universities in Eastern Canada where she currently consults on masters and doctoral studies. Allison holds our articles to a higher standard as she believes that peer-reviewed research is the most accurate source when writing on a given topic. Her articles are well researched but also enriched with her own experience. Ms King enjoys a healthy vegetarian lifestyle and steps out of her comfort zone by competing in various races and marathons across our country.