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Tyrosine is a powerful aromatic amino acid that is a building block for dopamine, epinephrine, norepinephrine, and thyroid hormones. Tyrosine supplements are nootropics and adaptogens that help with performance during times of stress. Many people find that it helps significantly with fatigue from stress.

Read this post to learn more about tyrosine, its side effects, and whether you should take it or avoid it.

Introduction to Tyrosine

Tyrosine is a neutral aromatic amino acid. It is a building block for proteins. It is found in many high-protein foods such as cheese, chicken, and eggs.

In the body, tyrosine is mainly used in the brain as a precursor to a class of neurotransmitters called catecholamines (dopamine, norepinephrine, and epinephrine). These catecholamines are used in many different cognitive functions.

To become a catecholamine, tyrosine requires two transformative steps. Firstly, it must be converted into dihydroxyphenylalanine (DOPA). Then, an enzyme (usually some form of a decarboxylase) turns the DOPA into one of the three catecholamines.

Tyrosine is a Precursor to Neurotransmitters

Tyrosine is a precursor to neurotransmitters, which include dopamine, norepinephrine, and epinephrine [R].

Elevated levels of tyrosine increase the production of these neurotransmitters when our bodies need more of them [R].

However, these situations have to be sufficiently challenging to require the extra release of neurotransmitters and subsequent depletion of these neurotransmitters. To maintain optimal neural performance, tyrosine supplementations prevented the neurotransmitters from depleting [R].

1) Tyrosine Replenishes Cognitive Resources Used in Memory

Tyrosine supplements restored certain cognitive resources used to increase working memory [R].

Working memory is responsible for the continued updating and maintenance of memory [R].

Studies showed that tyrosine only replenished certain cognitive resources when the resources get used up, so only challenging situations that require the use of these cognitive resources see an enhancement of the cognitive resources [R].

2) L-Tyrosine Is a Building Block of Thyroid Hormones

Thyroid hormones control energy production in the body, aiding in the repair and renewal of damaged cells while increasing resistance to constant stress [R].

In a bird study, chicks with induced tyrosine deficiencies had much lower levels of T3 and T4, common thyroid hormones, in their blood [R].

Birds that were given only phenylalanine supplements, which is the direct precursor to tyrosine, did not gain as much weight as birds given phenylalanine plus tyrosine supplements. This evidences that tyrosine supplementation helped in the growth of the chicks [R].

In rat studies where certain rats were put under constant stress, the stressed rats suffered from reductions in T3 and T4 thyroid hormones [R].

This is due to a decrease in the enzymes’ thyroid peroxidase and oxidase, which are crucial for thyroid hormone production. Many depressed patients also suffered from hypothyroidism [R].

Supplementation with tyrosine increased levels of the neurotransmitter norepinephrine, which increased thyroid hormone release. The tyrosine-supplemented rats not only gained less weight but also exhibited better cognitive function (as measured in maze tests and distance traveled) [R].

3) Tyrosine Increases Dopamine Levels in the Brain

Tyrosine supplementation increased dopamine levels in the striatum of the brain when animals are given treatments that increase dopamine demand [R].

Tyrosine administration also increased dopamine levels in the extracellular fluid of the brain. However, this effect was short-lived as excessive tyrosine in the brain also slowed down neuronal firing. This, in turn, brought the dopamine levels back to the original levels before tyrosine administration [R].

4) Tyrosine Helps with Performance During Stress

Tyrosine is a precursor to norepinephrine. Stress reduces norepinephrine levels in the brain  (locus coeruleus, hippocampus, and the hypothalamus) [R].

When rats were subjected to shock, norepinephrine levels dropped heavily. But, when tyrosine was injected into the rats, the norepinephrine levels remained constant. This is most likely caused by the fact that tyrosine enhanced the rate of norepinephrine production during stressful situations [R].

The added tyrosine caused the rats to show no behavioral deficits while rats that did not get the tyrosine supplements did show behavioral changes resulting from stress [R].

It was also hypothesized that tyrosine may improve physical performance only if the exercise being done produces enough cognitive stress and depletes dopamine or norepinephrine levels [R].

5) Tyrosine May Improve Attention Deficit Disorders

Clinical trials of using tyrosine to try to improve attention deficit disorder symptoms in humans showed some positive results. Of the 12 adults that volunteered for the clinical trials, eight of them showed some form of clinical improvement in two weeks [R].

However, after six weeks, all eight of the patients developed a tolerance to the tyrosine and improvements stalled. Further investigation into how tyrosine may be used to cure attention deficit disorders needs to be done [R].

Impaired neurotransmitter energy production may be a predisposition for attention deficit disorder [R].

Although this only accounts for 5 to 10% of the attention deficit disorder cases, it is more likely that such cases would benefit more from tyrosine supplementation [R].

6) Tyrosine to Treat Depression

Tyrosine was found to help depression in certain patients in some clinical trials. A single case, placebo-controlled, case involving a 30-year old woman suffering from depression showed marked improvement after tyrosine therapy [R].

Placebo treatments immediately showcased a return of depression symptoms. Continued tyrosine therapy brought back a marked improvement [R].

Further trials regarding two other patients with depression also showed improvement regarding symptoms [R].

However, a larger clinical trial of 65 patients did not support that tyrosine can be used as an antidepressant [R].

Possibly, this was because depression is dependent on many factors, not simply a lack of dopamine or norepinephrine. Tyrosine might only help depression patients with low dopamine and norepinephrine levels [R].

7) Tyrosine for Treatment of Parkinson’s Disease

Nine patients who had Parkinson’s disease were treated with tyrosine and probenecid. These patients showed an increase in homovanillic acid in the cerebrospinal fluid. The presence of homovanillic acid, a product of dopamine energy production, correlates to the fact that dopamine is being released in the brain [R].

Because Parkinson’s is strongly linked to the degeneration of neurons that release dopamine, increased levels of homovanillic acid could be good proof that tyrosine may be used to treat the disease [R].

8) Tyrosine Improves Inhibition

Tyrosine administration could help reduce unwanted tendencies [R].

One study describes these tendencies as inhibitory control. When patients were asked to perform a stop-signal task (where the patient clicks stop when a green arrow turns red), patients with tyrosine injections performed better than those with a placebo [R].

9) Tyrosine Improves Mood During Winter Blues

During stressful situations such as the cold or elevated altitudes, increased tyrosine levels improved mood by lowering the intensities of symptoms from the cold and lowered oxygen levels [R].

In a long-term study, patients in Antarctica were given tyrosine supplements daily over the summer and winter. However, during only stressful conditions in the winter months did the tyrosine supplements help to improve mood (by 47%) [R].

Summer conditions were not harsh enough to elicit a response [R].

Side Effects of Tyrosine Supplementation

1) Tyrosine Supplementation May Reduce Energy

Although many users state that tyrosine supplementation has benefited them tremendously, some other users have noticed a constant tired state that follows tyrosine supplementation. People take tyrosine supplements sometimes to help their tiredness, but in some cases, it actually made them more tired [R].

2) Tyrosine Supplementation May Cause Stiffness in the Shoulders and Neck

One user on tyrosine supplementation noticed stiffness in his/her shoulder and neck area. Other reviewers noticed similar side effects and agreed with that user [R].

3) Tyrosine Supplementation May Lead to Weight Gain

One user noticed that tyrosine supplementation led to unwanted weight gain. Three other reviewers corroborated this side effect [R].

Synergies with Other Supplements

Users of tyrosine supplements have also seen major improvements when combined with other supplements. Some users that use tyrosine to fight depression have noticed improvements when using tyrosine supplements along with 5-HTP, a tryptophan supplement. This is because 5-HTP increases serotonin in the brain while the tyrosine increases dopamine and norepinephrine, which all have to do with increasing mood [R].

The user mentions that other antidepressants like Prozac only increase serotonin, so tyrosine supplementation can help with increasing the release of other neurotransmitters [R].

Another user suffering from fatigue and low adrenal output also used the tyrosine supplement along with 5-HTP and found similar beneficial effects [R].

Combining the tyrosine supplements with a Super Cortisol supplement from Now Foods has helped another patient suffering from fatigue. The user mentions that energy levels have increased and that brain fog has disappeared after combined usage [R].

However, drug mixing should always be done under the supervision of a doctor. Please consult with your local physician before combining any supplements.

Drug Interactions

1) Tyrosine Interferes with the Uptake of the Parkinson’s Drug L-dopa into the Brain

Tyrosine supplementation may actually interfere with the treatment of Parkinson’s disease [R].

A common occurrence in the disease is the “on-off” phenomenon where levodopa is not as well absorbed or transported at times [R].

During the “off” times of the disease, the patients are barely able to walk at all or accomplish their everyday tasks, necessitating the need for a constantly “on” treatment [R].

Studies of nine patients showed that when amino acid-rich meals were taken, the levodopa concentrations in the blood decreased by 29% and the absorption was delayed by 34 minutes [R].

This happens due to the competing nature of levodopa and tyrosine into the brain. Higher levels of tyrosine can reduce the transport of levodopa into the brain reducing the effectiveness of the treatment [R].

2) Tyrosine Supplementation with Thyroid Hormone Pills May Lead to Overload of Thyroid Hormones

Tyrosine supplementation leads to an increase in thyroid hormones [R].

If this supplement is taken along with thyroid hormone pills, the body may produce too many of the hormones and cause unwanted side effects. Thyroid hormones control a wide range of bodily processes such as regulating the energy production in the body, aiding in the repair and renewal of damaged cells, and increasing resistance to constant stress, so excessive hormones may damage the body’s ability to perform these tasks [R].

Please consult a professional before taking tyrosine supplements when using other drugs.

Are You Struggling With Chronic Health Issues?

If you are struggling with chronic health issues – the way I used to – you probably have piles of lab tests that can potentially tell you a lot about your health. However, doctors never had enough time to explain it properly. They will only notice it if the lab flags your test results as outside of normal. But what if all your results are coming back normal, yet you know you are feeling nowhere near healthy? They may even tell you there is nothing wrong with you, and that it’s all in your head – I’ve been there.

Lab Test Analyzer is the tool I wish I had when I was dealing with all my health issues. Instead of normal, it will tell you the optimal values for lab tests. And if you are outside the optimal range, it will give you actionable tips and recommendations that will help you get there.

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The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.


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  • Maureen McGovern

    Ben, I’m sorry I can’t reply to your message. It won’t let me. RLS can be cured (along with MANY other illnesses) by supplementing with l-serine. It’s what needed to put glutamate where it belongs, in the NMDA receptor. Due to chemicals we are all l-serine deficient, hence the RLS and many, many other epidemics today.

    1. CIndy G

      Thank you Maureen. I had been wondering about the NMDA receptor for glutamate transfer. I just bought some lyserine. Ive been taking L-Glutamate for my gut health and I need to make sure it isn’t destructive.
      Also, I’ve been on Trosine, Taurine and SamE for years. I’ve just begun elevating Tyrosine as last year I was the victim of severe head wounds. Was very dizzy getting up or lying down. A lot of headaches. Still have a cheek bone that is depressed into my sinuses, but getting the Drs to repair it.
      I was worried about CTE and figured Tyrosine would be the best neurotransmitter enhancer to bulk up on. It made a difference. 2.5 grams in the morning and my dizziness decreased. After a year I tried to go back to 500mg and all the headaches and dizziness returned, along with memory issues. So I’m taking additional 2g Tyrosine in the afternoon and night. I think my body did adjust to the given Tyrosine load and needed more.
      The Drs are clueless in the preventative use of these amino acids, so it’s wonderful to find others who are finding solutions.

  • Ben

    Sioux Rogers, magnesium can make a big difference with restless legs. I haven’t had RLS chronically, but when I do, magnesium always helps. Some forms are better-absorbed and therefore could be more effective than other (cheaper) forms. My personal choice is magnesium malate, but any kind could be worth a try.
    Also, since you have been dealing with this for a while, you have probably already tried it, but doing stretches of the affected muscles can help a bit.

  • Sioux Rogers

    Confused with tyrosine vs L-tyrosine. I have HIT the wall with life time strugle of Willis-Eikbon Disease (WED) which is the official name for restless leg syndrome. Recently returned from a major disappointing trip to Johns Hopkins Hospital. They said I would be on methadone for the rest of my life. A bummer since I have never even smoke, let alone used any drugs of that sort. So on a self quest for a natural balance to lower the excess glutamate (the culprit) naturally, I am starting with tyrosine but am already confused. Any suggestions? I have wide open ears. Thanks, Very very desperate grown up lady.

  • Debra

    Can you take tyrosine with venlafaxine Clonazepam and levothyroxine?

  • JJ Lyman

    Thank you for all of this valuable and needed information.

  • kelly hearn

    Can I take this ONLY and discontinue my Levothyroxide pills?
    I purchased the Thyroid T-3 formula that has L Tyrosine 300mg tablets. They say to take 4-6 tablets daily.
    I am hypothyroid.
    Would love a response, thank you!

  • Ruby Owens

    What is the recomended dosage? You usually list them for your suppliments.

  • Doug

    I have seen cautions against using Tyrosine in cases of migraine, elevated cortisol, anger problems, anxiety, hyperthyroidism. Also in one well known book (The Mood Cure by Julia Ross) there is a firm warning about Tyrosine for those with melanoma history, but no references are given. Why no mention of these possible contraindications? I can’t get over how much online (and published) content about supplements fails to collate all the known or suspected risks.

  • Janice B Smith

    Correction to my previous comment Pedal should be Lexapro

  • Janice B Smith

    I have been taking Pedal to for several years which helped with anxiety but left me feeling depressed and constant mind fog. After taking 50 mg of L Tyrosine twice a day I have more energy and concentration has improved tremendously.

  • Håkon Martin NIlsen Bjerke

    You still need iodine and selenium to make the T4 and T4 out of tyrosine, right???

  • Neta Mills

    Using to help depression and memory

  • Jason

    Hello! I have enjoyed your site frequently the last year or so. I am starting my own site revolving specifically around the Val158Met ++ snp. I like the idea of having anecdotal evidence like you did using upvoted side effects from a vitamin site, but I would personally place emphasis on the fact that it is anecdotal. If one could encourage the budding biohackers to self hack so to speak and give anecdotal evidence, then one could aggregate that data. I think it is important. Take for instance CBD. I live in Denver and take it. I didn’t realize it also would make me and my wife lose 40 pounds. That isn’t a well known side effect. In low doses it provides energy but in high doses it has anti anxiety applications. I personally would preemptively advertise that this site is for educational and ENTERTAINMENT purposes only. I like the FDA markers but might as well emphasis entertainment and encourage even more interaction with site visitors, (chat boards etc) and avoid and pre empt potential scrutiny.

    My wife reached out to you a couple weeks ago and was going to speak to someone about your CFO needs but there were technical difficulties. I am currently working on a couple of site ideas. I have an education as a Network Engineer and years of experience in Advanced technical support. I was also a musician for years and have those connections and experience. Absolutely interested in helping grow and advance your project. Feel free to reach out. And if not, then best of luck and thanks for your work!

    1. Shea

      Jason, thanks for your comment. Please see our hiring page for more info:

  • jon miller

    one of the best things for thyroid problems,try it,you will be glad you did,helps with depression

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