Last updated: August 11, 2021

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Welcome to our big phenylalanine test 2021. Here we present all the products we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the internet.

We would like to make your purchase decision easier and help you find the best phenylalanine preparation for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy a phenylalanine product.




The most important facts

  • Phenylalanine is an amino acid that occurs naturally as a protein component. It was first synthesised from legumes in 1879.
  • Phenylalanine belongs to the essential amino acids and must therefore be taken in by humans through food. In the body, this amino acid plays an important role in building protein, muscles, other amino acids such as tyrosine and in hormone production.
  • There are two structures of phenylalanine, the L-form and the D-form. The L-form is natural and is absorbed by humans as an essential ingredient. The D form, on the other hand, is produced synthetically. It is believed that this form also has important functions in the body.

The Best Phenylalanine: Our Picks

Guide: Questions you should ask yourself before buying phenylalanine

Is the natural requirement of phenylalanine already covered by food?

Some of the amino acids can be synthesised by the body itself, others have to be taken in through food - these amino acids are called essential amino acids. Phenylanine is one of them.

For this reason, a balanced and conscious diet is the key to a fully functional and healthy metabolism (1)

The amino acid is found in many common foods and is mainly absorbed in the intestine. Amino acids form proteins, among other things, which is why you will find phenylalanine above all in foods with a high protein content. (2)

Phenylalanine is one of 23 amino acids, the components of proteins. (Source: pixabay.com )

Phenylalanine and tyrosine are particularly abundant in the following foods:

  • Nuts
  • Seeds
  • Wheat germ
  • Vegetables
  • Dairy products

Soybeans are a very high supplier. In 100 g there is about 1970 mg of the amino acid. In combination with vitamin C and vitamin B6, the amino acid can be absorbed and processed particularly efficiently by the body.

Phenylanine can also be used to treat depression. 1-Phenylalanine in combination with 1-deprenyl leads to an improvement in patients' depression when taken orally and intravenously. This can be attributed to an increased 1-phenylalanine concentration in the brain. (3)

When might you consider phenylalanine as a dietary supplement?

As explained earlier, under normal circumstances, the actual need for phenylalanine can already be met with a balanced diet. S

f you want to avoid foods that contain large amounts of phenylalanine, either because of an allergy, intolerance or because you don't like the taste, you can take phenylalanine in powder form, i.e. as a food supplement.

In certain situations with a corresponding clinical picture, it can also be assumed that there is an additional need. For example, in the case of chronic pain (remedy possibly with D- or DL-phenylalanine), in the case of depression or in the case of a general lack of amino acids in the body caused by diseases or Parkinson's disease. (Source: 123rf.com / Katarzyna Białasiewicz )

The supplement could also be interesting for you if your body is exposed to high stress or physical strain, such as hard training, a stressful daily routine or when preparing for a competition.

How much phenylalanine can you take daily?

For healthy adults, the daily requirement of phenylalanine per kilogram of body weight is about 14 mg, according to the World Health Organisation (WHO). The German Nutrition Society (DGE) even sets the value at 25 mg/kg body weight.

The following table shows the possible phenylalanine and tyrosine requirements in different years of life.

Adults

Groups of people Age Daily recommended amount of phenylalanine & tyrosine in mg/kg body weight
Infants Under 1 month, Under 2 months, Under 4 months, ½ to under 1 year 238, 158, 112, 59
Children & adolescents 1 to under 3 years, 3 to under 15 years, 15 to under 19 years 40, 30, 28
25

How much you can actually consume depends, of course, on other factors such as high stress, high physical exertion through sport and other factors already mentioned.

People suffering from phenylketonuria are treated with a low-phenylalanine diet. It is very important that the foods consumed are very well selected so that malnutrition does not occur despite the restricted diet. (4)

How should you take phenylalanine?

Phenylalanine supplements are usually available in powder or capsule form. Each product usually tells you how and how many capsules to take. The capsules should normally be taken with sufficient water or juice.

Remember, however, that this is only a food supplement. You should not forego a normal and balanced diet under any circumstances.

If you want to be on the safe side, you can always seek advice from a doctor.

Decision: What types of phenylalanine are there and which is the right one for you?

Basically, you can distinguish between 3 different types of "phenylalanine":

  • L-phenylalanine
  • D-phenylalanine
  • DL-phenylalanine (DLPA)

What is L-phenylalanine and what are the advantages and disadvantages of L-phenylalanine?

This type is the natural form of phenylalanine. It is found in many protein foods such as salmon, egg, meat and many vegetables.

It is an essential amino acid and must therefore be taken in with food. In the body, it is processed into important messenger substances and amino acids.

Advantages
  • The daily requirement is usually already covered by a balanced diet under normal circumstances
  • Is responsible for the production of important endogenous substances
  • Phenylalanine can indirectly lift the mood and improve performance
  • Helps the body through stressful times (little sleep, a lot of work, great athletic performance, etc.)
Disadvantages
  • The substance must be avoided in cases of phenylketonuria
  • An overdose can lead to some side effects in rare cases

What is D-phenylalanine and what are its advantages and disadvantages?

This is the D form of the amino acid phenylalanine. This form does not occur naturally, but is produced artificially. D-phenylalanine is a non-proteinogenic amino acid and is not metabolised by the human body.

Regarding the effectiveness of D-phenylalanine, there are currently more assumptions than firm scientific evidence.

Advantages
  • It possibly blocks certain enzymes that break down painkillers in the central nervous system - result: analgesic effect
  • Has antidepressant abilities
  • Relieves chronic pain
  • Uplifts mood
Disadvantages
  • Should only be taken in consultation with a doctor
  • Must be taken in advance for an effect to occur

What is DL-phenylalanine and what are its advantages and disadvantages?

DL-phenylalanine, also known by the abbreviation DLPA, is a preparation that consists of a combination of L-phenylalanine and D-phenylalanine. The respective properties of the individual substances are combined in one product.

Advantages
  • May help with chronic pain
  • Pain-relieving effects in migraine (chronic), menstrual pain, toothache
  • May support pain-relieving effects related to acupuncture
  • Mood elevating effect
  • May help with withdrawal from alcohol and drugs
Disadvantages
  • Taking too long or too much can cause side effects including headaches and high blood pressure
  • Pregnant women should be very careful when taking

Buying criteria: You can use these factors to compare and evaluate phenylalanine supplements

In the following, we would like to show you which factors you can use to compare and evaluate phenylalanine preparations.

This will make it easier for you to decide whether a particular phenylalanine preparation is suitable for you or not.

In summary, these are:

  • Active ingredient
  • Dosage
  • Manufacturer's information and warnings
  • Control procedures, certifications, tests

In the following paragraphs we will explain to you what is important in the individual criteria to make your purchase decision easier.

Active ingredient

Since there are different types of phenylalanine, you should check online shops or similar places to find out which product you are really looking at.

If you take a phenylalanine preparation, it will usually be L-phenylalanine, which also occurs naturally in food.

There are also D-phenylalanine preparations and DL-phenylalanine preparations. However, you should not take these products on your own, but consult a doctor. (Source: 123rf.com / Vitaliy Vodolazskyy )

Dosage

Not every preparation has the same dosage. There are products with a dosage of 750 milligrams per serving or 500 milligrams.

These are the most common dosages in Germany. The dosage is either mentioned in the ingredients or often made clear in the product name on the label.

For example, if it says "L-phenylalanine 500", one capsule or daily dose contains 500 milligrams of the active ingredient, in this case the amino acid.

Manufacturer's information and warnings

When looking for the right preparation for you, it is advisable to read the manufacturer's information and warnings.

These can give you important information about taking the product, dosage and storage. Warnings regarding children and pregnancy can also be found here.

Control procedures, certifications, testing

It is important that the active ingredient is really pure and that there are no more unfavourable by-products. These can arise during the manufacturing process.

To check how pure a substance is, manufacturers carry out a test using chromatography, among other things. An HPLC is used for this.

The production should also take place under the prescribed standards and be accompanied by extensive control procedures. Germany is very strict in these areas, also with regard to the food industry.

Such standards and certificates can concern, among other things, the production of phenylalanine itself, as well as the respective raw materials from which it is made.

If you want to be on the safe side when making your choice, you can look for these standards and certificates among the suppliers and manufacturers themselves. You might come across the following:

type standard or certificate short info
control procedures ISO 13485 medical devices: Quality management systems - Requirements for regulatory purposes/ Requirements to be met in the development, implementation and maintenance by suppliers and manufacturers of medical devices
Quality standard ISO 9001 To improve company performance at all levels for more transparency, sustainable improvement of customer satisfaction and reduction of error rate and costs
Quality standard HACCP Engl: Hazard Analysis and Critical Control Points, a quality tool created for the handling and production of food
Good Manufacturing Practice GMP guidelines on production processes and quality assurance in the manufacture of medicines, active ingredients, animal feed, cosmetics, etc.

Facts worth knowing about phenylalanine

How does phenylalanine affect your body?

The natural form L-phenylalanine, which is found in many foods, is responsible for the production of important substances in the body. One of these is the amino acid tyrosine.

Tyrosine, which is made from phenylalanine, also performs important functions.

It is helpful in the production of hormones (thyroid hormone thyroxine, insulin, etc.), neurotransmitters and catecholamines, such as dopamine, noradrenaline and adrenaline. These act as messengers to stimulate the nerve cells and mediate stimuli.

When dopamine is released, your body gets the message that it is doing well. So you feel motivated and good. Indirectly, phenylalanine influences your mood.

Is phenylalanine also contained in sweeteners?

As mentioned above in the article, many protein-rich foods in the normal diet contain enough phenylalanine to meet the body's daily needs under normal circumstances.

However, those who have to watch out for phenylalanine-containing foods due to certain conditions, diseases or metabolic disorders, such as phenylketonuria, should also watch out for the sweetener aspartame. (5)

It contains up to 40 % phenylalanine. All products sweetened with this substance must be labelled accordingly and indicate that they contain phenylalanine.

Can overdosing lead to side effects?

If you accidentally take more phenylalanine than recommended, it is not the end of the world.

As long as you are healthy, your body will find its balance again relatively quickly. The excess amount that it does not need is excreted.

In rare cases, side effects may occur. These include headaches, high blood pressure and anxiety.

When does phenylalanine become dangerous?

Additional phenylalanine could only be dangerous if you are not allowed to consume it due to a certain disease.

These include severe liver diseases, increased dopamine levels, schizophrenia or the use of certain antidepressants.

Phenylketonuria is a metabolic disorder that affects 1 in 7,000 newborns in Germany alone. (5) The body lacks a liver enzyme that enables the conversion of phenylalanine into tyrosine. The phenylalanine therefore accumulates in the blood.

If the level is too high, this eventually leads to poisoning. This shows in the skin, hair and brain. Mental development is slowed down, seizures, brain disorders and skin disorders are the result. Affected persons must therefore follow a strict diet for life.

Picture source: 123rf.com / Trojanowski P.

References (5)

1. hagavan, N. V., & Ha, C.-E. (2011). Protein and Amino Acid Metabolism. Essentials of Medical Biochemistry, 169–190.

2. Corinna Melanie Brichta (2013): Untersuchung von Phenylalanin und Tyrosin im Mikrodialysat von Patienten mit Phenylketonurie und Hyperphenylalaninämie .

3. Birkmayer, W., Riederer, P., Linauer, W., Knoll, J. (1984). L-deprenyl plus l-phenylalanine in the treatment of depression. Journal of Neural Transmission, 59(1), 81–87.
Source

4. Weetch, E., & MacDonald, A. (2006). The determination of phenylalanine content of foods suitable for phenylketonuria. Journal of Human Nutrition and Dietetics, 19(3), 229–236.
Source

5. Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive1 EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS)2, 3 European Food Safety Authority (EFSA), Parma, Italy.

Why you can trust me?

Wissenschaftlicher Artikel
hagavan, N. V., & Ha, C.-E. (2011). Protein and Amino Acid Metabolism. Essentials of Medical Biochemistry, 169–190.
Wissenschaftlicher Artikel
Corinna Melanie Brichta (2013): Untersuchung von Phenylalanin und Tyrosin im Mikrodialysat von Patienten mit Phenylketonurie und Hyperphenylalaninämie .
Wissenschaftliche Studie
Birkmayer, W., Riederer, P., Linauer, W., Knoll, J. (1984). L-deprenyl plus l-phenylalanine in the treatment of depression. Journal of Neural Transmission, 59(1), 81–87.
Go to source
Wissenschaftlicher Artikel
Weetch, E., & MacDonald, A. (2006). The determination of phenylalanine content of foods suitable for phenylketonuria. Journal of Human Nutrition and Dietetics, 19(3), 229–236.
Go to source
Wissenschaftlicher Artikel
Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive1 EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS)2, 3 European Food Safety Authority (EFSA), Parma, Italy.
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