Skip to content


The methionine is part of the essential amino acids, which means that the body is unable to synthesize it . Therefore, it is very important to get it incorporated into the diet, since it is the only way to provide this amino acid to the body.

What is methionine

This essential amino acid is, together with cysteine, one of the few amino acids that contain sulfur in its chemical composition. That is why it is also known as sulfur amino acid.

Methionine belongs to the family of nonpolar or hydrophobic amino acids. This means that it has groups of a hydrocarbon nature, which is why it repels water. Like all amino acids, it is characterized by having an amino group and a carboxyl group, both attached to an asymmetric carbon atom.

This essential amino acid is also known as L-Methionine, Met, or just M for short. Its chemical formula is HO2CCH (NH2) CH2CH2SCH3 and its molecular formula is C5H11NO2S.

Anabolism and metabolism

As methionine is an essential amino acid, it means that the body is not capable of producing it by itself. The following explains the process of its biosynthesis or anabolism and its metabolism.

Anabolism or biosynthesis

This essential amino acid is synthesized in plants and microorganisms . For this, there is only a single route, in which aspartic acid and cysteine ​​participate. First, aspartic acid is converted to homoserine through beta aspartate semialdehyde dehydrogenase.

During this process, methylene groups are introduced, and subsequently, homoserine is converted to O-succinyl-homoserine. The cysteine ​​then reacts with O-succinyl-homoserine to produce cystanionine. Finally, for the formation of methionine, the thiol group undergoes a methylation from phosphates.

Among the different enzymes that participate in the anabolism of this essential amino acid are cystathionine beta lyase, homoserine acetyltransferase, aspartokinase, aspartate beta semialdehyde dehydrogenase, among others.


Regarding its metabolism, methionine passes into S-adenosylmethionine, an important co-substrate in the transfer of methyl groups. Subsequently, this common co-substrate demelites to S-adenosyl homocysteine, which is hydrolyzed to homocysteine.

Homocysteine ​​can follow two metabolic routes to be eliminated from the body. The first is by remethylation, where homocysteine ​​is recycled to be rememethylated to methionine.

The second route is through transulfuration, which consists of the transformation of homocysteine ​​into cystanionine and later to cysteine. Cysteine ​​is then metabolized to sulfate, which is excreted in the urine.

Properties of methionine

This essential amino acid has many properties and benefits, which we will see later. Regarding its properties, methionine is characterized by being an excellent antioxidant, due to its great ability to fight free radicals .

In addition, thanks to this amino acid, the body can synthesize two other non-essential amino acids, taurine and cysteine. It also has antidepressant and antiallergic properties . The latter is due to the fact that it reduces the levels of histamine in the body.

Also, another of the properties that stand out of this amino acid is its ability to transport fat and transform it into energy. Now, let’s see all its properties:

  • It favors the function of Selenium.
  • It helps in the breakdown of fats and to avoid excess cholesterol.
  • It transports fat and transforms it into energy.
  • It is part of the functions of the lymphatic system , spleen and pancreas in an active way.
  • Reduces the level of histamine .
  • Essential for the synthesis of taurine and cysteine.
  • It has antioxidant properties.
  • Provides protection against radiation.
  • Helps remove heavy metals from the body.

Health benefits

Methionine, in addition to having all the properties mentioned above, also provides various benefits:

Health in bones, skin and hair

This essential amino acid is an excellent source of sulfur for the body . For this reason, the health of our bones, nails, skin, and even hair, is benefited. That is why it helps to strengthen the structure of the hair, helps fight alopecia and also strengthens the nails.

Lowers cholesterol

By helping to break down fat and transform it into energy , it prevents it from accumulating both in the arteries and in the liver . That is why it is beneficial to reduce and prevent bad cholesterol.

Helps to treat and prevent various diseases

In relation to the above, methionine also helps prevent liver and cardiovascular diseases. It is also used as an aid in the treatment of Parkinson’s disease . But not only that, it is also used to prevent and treat mental illnesses.

This is because it promotes the feeling of well-being and improves moods . Therefore, it helps prevent anxiety and depression thanks to its anxiolytic and antidepressant properties. In addition, it is an excellent natural relaxant, making it ideal for preventing stress , relaxing, and helping you sleep.

Helps with muscle strengthening and cartilage formation

This essential amino acid participates in the improvement of muscles , preventing their weakening, thus improving muscle performance. This is why many athletes take methionine supplements.

In addition, by containing sulfur, this essential amino acid participates in the formation of cartilage, since the joints need this element. Therefore, it helps to form cartilage cells, but not only that, it also reduces inflammation and calms the pain caused by osteoarthritis .

Functions and importance of methionine

As mentioned previously, methionine is essential for the synthesis of two non-essential amino acids. That is why one of its main functions is to synthesize cysteine ​​and taurine.

But in addition to this, it plays an important role in the transformation of fat into energy. So, as already explained, it prevents the accumulation of fat in the arteries and liver, which helps prevent diseases and lower cholesterol .

It also works as an excellent natural antiallergic, participates in the elimination of toxins, is an important antioxidant , stimulates the formation of cartilage and helps creatine fulfill its function of supplying energy for the movement of muscles.

In the event of a methionine deficiency in the body, this can have the following consequences:

  • Because it helps to break down fat, in case of a deficiency of this essential amino acid, the accumulation of cholesterol could increase.
  • It could also generate a buildup of free radicals.
  • Increases the chances of developing histadelic schizophrenia.
  • It increases the propensity for different infections.

How to provide methionine to the body?

The main way to provide methionine to the body is through the consumption of foods that have this essential amino acid. However, there are also supplements that are available in various forms.

Supplements of this essential amino acid can come in capsules, pills, and even as a powder. In general, these supplements are consumed by athletes, since the necessary doses of this amino acid can be obtained through diet.

Recommended dose

The RDA for methionine for adults is about 800 to 1000 milligrams. However, for athletes and high performance athletes who want to burn fat and gain more muscle mass, they can take up to 1500 milligrams maximum per day.

Supplements of this essential amino acid are usually available in 500 mg capsules or tablets, which should be taken half an hour before each meal. However, it is best to go to a professional who indicates the recommended dose for each person and particular case.

In what foods is methionine found?

Methionine is found in a large number of foods rich in protein , as it is precisely a proteinogenic amino acid. Foods such as meat and dairy contain high percentages of methionine, however, many vegetables, seeds and legumes also have it.

That is why people who eat a vegetarian or vegan diet can also get enough of this amino acid through a varied diet.

Foods of animal origin

  • Beef.
  • Pork Meat.
  • Chicken.
  • Fish such as grouper, mackerel, sardines, among others.
  • Eggs.
  • Milk.
  • Dairy products like cheese.

Vegetarian food

  • Legumes (lentils, chickpeas, peanuts, beans, etc., however, it is necessary to combine them with cereals).
  • Vegetables (purslane, spinach, broccoli, and others).
  • Cereals (rice, oats, barley …).
  • Nuts and seeds (pumpkin seeds, hazelnuts, chia and sesame seeds …).

Side effects or contraindications

As mentioned above, this essential amino acid can be provided easily and correctly through a varied and balanced diet. In this way, we can ensure that we consume the necessary methionine without side effects.

In cases where Met supplements are taken, side effects are likely. Some people may be allergic to the supplement, leading to allergy reactions such as itching or swelling.

Also, side effects may include shortness of breath, feeling nauseous, and even having drowsiness and tightness in the chest. In fact, the excessive consumption of supplements of this essential amino acid is associated with diseases such as angina pectoris and others.

If you develop any of these symptoms after consuming this supplement, it is essential that you receive medical assistance. As for contraindications, if you are taking any medication, the ideal is to consult your doctor, since methionine can interact with some drugs .

Also, Met supplements are completely contraindicated in pregnant women . Similarly, people with kidney or liver problems should not take these types of supplements.

Methionine along with other substances

Regarding the functioning and interaction of this essential amino acid with other substances, we have the following:

Methionine and selenium

As already mentioned , methionine helps in the absorption of selenium , but not only this, since it also works together with it. Together they are called seleniomethionine, and they help support the immune system, protect the body from free radicals, and strengthen the function of the thyroid gland.

Methionine and zinc

For its part, the consumption of methionine and zinc favors the absorption of this mineral. In addition, it helps that zinc is not wasted or discarded by the body, since it becomes more resistant. In fact, it causes the zinc to become chelated, making it more difficult for it to bind with intestinal fibers, phytic acid, and phytos.

Methionine and Cystine

As previously noted, methionine is essential for the synthesis of cystine. Both amino acids have sulfur, which is why they promote good skin, hair and nail health.

S-adenosylmethionine (Methionine and adenosine triphosphate)

This union is sold as a supplement, and is of great help in regulating mental states, which is why it is excellent for preventing depression . In addition to this, it helps with the transfer of methyl groups and in molecular chemical transactions.

Methionine and lysine

These two essential amino acids work together for the synthesis of carnitine , a non-essential amino acid. Carnitine is very useful for high-performance athletes as it helps to improve sports performance, accelerates recovery and increases the capacity for high-intensity activity.

Data to take into account

It is important to bear in mind that if you are consuming methionine supplements, the recommended doses must be respected. In addition, it is best to go to a specialist so that you know with certainty what dose you should consume .

If you are not an athlete, remember that it is not necessary to take supplements unless the doctor recommends it. If you eat a varied diet that contains foods rich in protein such as meat, fish, etc., you can have the necessary supply of this essential amino acid.

In case you are vegetarian or vegan, you can also obtain the Met necessary for your body. Just remember that legumes, despite containing methionine, do not provide enough of this essential amino acid. That is why you should combine them with cereals such as rice, oats, barley, corn, among others.

Website | + posts

Hello Readers, I am Nikki Bella a Psychology student. I have always been concerned about human behavior and the mental processes that lead us to act and think the way we do. My collaboration as an editor in the psychology area of ​​Well Being Pole has allowed me to investigate further and expand my knowledge in the field of mental health; I have also acquired great knowledge about physical health and well-being, two fundamental bases that are directly related and are part of all mental health.

Leave a Reply

Your email address will not be published. Required fields are marked *