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L Tyrosine and Thyroid

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L-Tyrosine is a natural amino acid that can be used to improve hypothyroid problems.

L-Tyrosine is the synthetic form of a naturally occurring amino acid produced to stimulate thyroxine, the hormone produced by the thyroid gland. The body needs the amino acid Tyrosine for many functions. It is especially important in thyroid performance, and a lack of L-Tyrosine in the diet can create hypothyroid conditions.

Synthetic L-Tyrosine is known by several names including:

  • Acetyl-L-Tyrosine
  • N-Acetyl L-Tyrosine
  • Tirosina
  • Tyr
  • Tyrosinum
  • 2-amino-3-propionic acid
  • 4-hydroxyphenyl propionic acid


Amino acids and specifically L-Tyrosine are responsible for the structure of proteins in the body. It is required for the body to produce such important neurotransmitters as L-dopa, epinephrine, and the body’s natural feel-good “drug” dopamine.

Without adequate amounts of L-Tyrosine in the body, depression and other common symptoms of an underactive thyroid known as hypothyroid become more prominent.

L-Tyrosine works in conjunction with iodine which is normally found in many forms of seafood, but most notably in seaweed such as kelp.

Cooking can leech the iodine out of foods. The difficulty, and in some cases the dangers, of eating raw seafood and seaweed make iodine supplements a better alternative for many people who want to boost L-Tyrosine action.

Facts About Hypothyroidism

Hypothyroid, or underactive thyroid, causes a 6% reduction in metabolic rates.

Hypothyroidism causes low body temperature. People with underactive thyroids are often between two and four degrees colder than normal.

Low body temperature causes a further reduction in metabolism and can be as much as 24% lower than normal.

Hypothyroidism also creates poor blood sugar regulation and can lead to diabetes.

Blood tests for hypothyroid conditions are not 100% accurate, and hypothyroidism is often undiagnosed.

What are L-Tyrosine Supplements Used For?

Along with adjusting thyroid production, and creating a reversal of hypothyroid, L-Tyrosine is used in treating depression, ADHD, narcolepsy, Alzheimer’s disease, chronic fatigue, heart disease, stroke, erectile dysfunction, as an appetite suppressant and even for support during cocaine and alcohol withdrawal. L-Tyrosine is also a commonly used supplement for treatment of Parkinson’s Disease.

Topical L-Tyrosine is also an ingredient in many skin care formulas to help reduce wrinkles and age-related damage.

Where to Find L-Tyrosine

Like other amino acids, the body makes L-Tyrosine naturally. Sometimes, however, there is a lack of these amino acids and it causes hypothyroidism. To prevent it, you can boost your L-Tyrosine levels through foods or supplements.

L-Tyrosine is found in many typical food sources. Foods high in Tyrosine include:

  • Dairy products
  • Meat
  • Green vegetables
  • Kale

However, people who are dieting or have a poor diet may not be eating enough of this important amino acid. When L-Tyrosine in foods is low, a synthetic form must be taken to keep the thyroid working normally.

Over the counter L-Tyrosine supplements come in several forms, all are easy to take. You can get them in tablets, capsules and powder form. There is some evidence that NALT (N-Acetyl L-Tyrosine) powder is absorbed faster, and made more instantly available for thyroid function than pills and capsules.

Experts and dieticians agree on the typical daily dose of L-Tyrosine supplements. You should take 500mg to 1000mg two or three times a day about a half hour before eating with a physician’s approval.

However, it is safe to begin an L-Tyrosine regimen without a doctor’s evaluation, provided you are not taking other drugs or herbal medications, and do not have any of the conditions that L-Tyrosine can aggravate.

When taking L-Tyrosine supplements on your own it is best to start with very low doses of 50 to 100mg two times a day a half hour before meals. Slowly increasing the dose to the normal recommendations as tolerated.

Children should not be given L-Tyrosine without a doctor’s orders.

Using L-Tyrosine

Eating foods high in Omega-3 fatty acids such as fish and avoiding alcohol and tobacco consumption will help increase the ability of L-Tyrosine to alleviate hypothyroidism. Fruits and foods with high antioxidant levels are also beneficial. Avoid foods such as:

  • Broccoli
  • Cabbage
  • Brussels Sprouts
  • Spinach
  • Turnips
  • Soybeans
  • Peanuts
  • Linseed
  • Mustard Greens
  • Cauliflower

All which interfere with the proper function of the thyroid gland, and can over stimulate the thyroid causing overdose of L-Tyrosine.

When treating severe hypothyroid symptoms such as goiters, alternating hot and cold compresses against the neck can help along with your thyroid medications,  and L-Tyrosine supplements.

Benefits of L-Tyrosine

Along with the known benefits of L-Tyrosine & underactive thyroid performance, L-Tyrosine is necessary for the production of skin pigment (melanin) as well as healthy, strong hair and hair color. L-Tyrosine is also a necessary ingredient for adrenal and pituitary function.

The most common reason for taking L-Tyrosine supplements is for thyroid function. When taking L-Tyrosine for thyroid function, it is helpful to take an iodine supplement as well or eat foods high in iodine such as kelp.

Many people, even in the well-developed countries where some foods are supplemented with iodine have severe iodine deficiencies that lead to many problems, not the least of which is hypothyroidism.

Hypothyroidism causes weight gain, difficulty losing weight as well as many other health problems.

When You Should Not Take L-Tyrosine Supplements

If you are already taking prescription thyroid medications, taking additional L-Tyrosine supplements can interfere with their action. Before adding L-Tyrosine supplements to medications such as Levothroid, Unithroid, Synthroid,  or Levoxyl consult with your physician. It can also cause an overdose of those medications, and create dangerous, even fatal levels of thyroxine (the thyroid hormone) in the system.

Tell Your Doctors When…

You are pregnant or trying to get pregnant before taking L-Tyrosine.

Have allergies to foods, food dyes or preservatives.

Are breastfeeding.

May have, or are being treated for Graves disease, phenylketonuria (PKU), or are on hypothyroid medications.

Are taking any other prescription medications or herbal supplements or non-prescription medications that may interfere with, or result in problems from taking L-Tyrosine.

Testing for Proper Thyroid Function

If you feel your thyroid is not performing, you can ask your doctor to test for proper thyroid function. They will look for proper levels of T4 and T3 (the thyroid hormone) in your blood.

Do not rely on typical physical checkups or blood tests to find thyroid problems. Those blood tests do not look for the thyroid hormone, and a simple physical exam will not reveal the problems associated with thyroid conditions because they can be vague such as headaches, fatigue, muscle aches.

It isn’t until symptoms of hypothyroid become extreme that your doctor may automatically request the tests to check for low levels of T3 and T4.

People who have high blood pressure should also refrain from taking any L-Tyrosine.

How to Naturally Boost the Performance of L-Tyrosine Supplements

When taking L-Tyrosine supplements, it is a good idea to help your body assimilate them. Aerobic activities help increase the oxygen in the blood and improve blood flow, carrying L-Tyrosine better and restoring enzyme and hormone levels. Such activities include:

  • Yoga
  • Swimming
  • Cycling
  • Walking or Treadmill
  • Elliptical Machines

Side Effects of L-Tyrosine & Hypothyroid Supplements

Regular doses of L-Tyrosine do not cause serious side effects. Common problems such as heartburn, stomach activity such as rumbling or feeling bloated, nausea and gas are common with L-Tyrosine supplements.

However, overdoses of L-Tyrosine can cause some serious side effects such as increased body temperature, loss of coordination, hallucinations, agitation, overactive reflexes, rapid heart rate and in rare cases eosinophilic myalgia syndrome, a condition that can be fatal and affects the blood, muscles and major organs including the skin.

Homeopathic Remedies for Hypothyroid

If you are experiencing symptoms of hypothyroid including difficulty losing weight, low body temperature, fatigue, difficulty concentrating or others, but do not test low enough in regular thyroid tests, you might consider taking L-Tyrosine supplements available over the counter.

If you have any questions about whether L-Tyrosine supplements are right for you, ask your doctor. They can help you determine the best course of action to stimulate an underactive thyroid with L-Tyrosine.

Next Article: Thyroid Health | How to Boost T3 and T4 Levels