Last updated: August 15, 2021

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You've heard in the gym that taking aspartic acid produces more testosterone in the body and you're hoping for better training results and better sperm quality? The talk with your mate hasn't quite convinced you yet and you would like to gather some more scientific background knowledge? Then the following article is just the right thing for you to bring some "light into the darkness".

The following aspartic acid test 2022 explains exactly what aspartic acid actually is, where it is produced, how it works and whether you should take it in capsule or powder form or whether you can do without it. In the following, we substantiate all findings with the corresponding scientific studies in order to offer you real added value and to inform you about the topic. So whether you are an absolute fitness freak or are planning your first child with your girlfriend, you should really read on here.


  • Aspartic acid in its natural L-form is one of the proteinogenic alpha-amino acids. It is produced in the body by transamination of the homologous keto acid oxaloacetate. In the urea cycle, L-arginine is formed from aspartic acid via several reactions. This amino acid releases the urea and thus has a detoxifying effect on the metabolism.
  • According to some scientific studies, the synthetic D-aspartic acid (D-form) (1) can decisively intervene in the neuroendocrine nervous system of humans. As a neurotransmitter, D-aspartic acid (D-AA) is involved in the production of testosterone and progesterone.
  • According to a study by an Italian research group, D-AA can increase testosterone levels in men. (2) Increased testosterone levels can lead to greater muscle growth during muscle training.

The Best Aspartic Acid: Our Picks

Buying and evaluation criteria for D-aspartic acid

In the following, we have listed some aspects that will help you find the best way to integrate D-aspartic acid into your daily routine. You can also save money and avoid unpleasant side effects. With a preparation like aspartic acid, you should make sure that it is of very high quality, if only for the sake of your health. Look for quality seals such as "made in Germany", "100% pure" or "tested by laboratory xyz" and check the correctness, e.g. on the website of the consumer advice centre.

By making the right choice for you, you can save money and avoid unpleasant side effects. You also make sure that you don't give your body anything it doesn't need. Therefore, always make sure that you take a balanced amount of the active ingredient and that it is of high quality. If you are unsure, ask to see the manufacturer's certificates.

Dosage form

We have already learned that, in addition to D-aspartic acid powder, you can also buy pills and liquid in an ampoule. You now have to choose the dosage form that suits you best from these options. Of course, the powder has the advantage that you can adapt it most precisely to your needs. Pills and ampoules already have fixed amounts of active ingredients. The dosage form can also have an effect on the price. On average, powders are cheaper than pills and pills are cheaper than ampoules.

Pills have the advantage that they can be taken "on the go" or "in between, very quickly", e.g. with a sip of water, whereas the powder always has to be processed in a drink first. Pills and ampoules allow better control of the training success, as you can dose both very precisely during the training session. However, if you come to your fitness training with a protein shake anyway, you will certainly be pleased with the D-aspartic acid powder, which you can simply mix in.


It is often said that the dose makes the poison. Although D-aspartic acid is not life-threatening, it can also work against the desired training success if taken in the wrong dosage. Studies have shown that a cyclical intake of small amounts of D-AA is most promising for the beginning. A dose of no more than 3 grams every day for 2-3 weeks, divided into a morning and an evening ration and a break of 1-2 weeks at the end of the intake period is considered a recommendation (3).

An amount of 3 grams per day is recommended.

Depending on how the body reacts to the administration of D-aspartic acid, the athlete can slowly increase the amount to e.g. 5 grams per day after the first intake cycle. Of course, extreme caution must be exercised, because testosterone overproduction quickly leads to unattractive results (e.g. gynaecomastia), which are associated with the conversion of excess testosterone to oestrogen via the aromatase enzyme controlled by D-AA. To prevent this effect, you would need to use an aromatase inhibitor such as zinc or Resverartrol.

Package size

When it comes to pack size, it is advisable to know if you just want to try D-AA for a while, or if you are ready to use D-AA for a longer period of time. Someone who only wants to try it out can safely take a 100gr. D-AA powder pack and dose the amount themselves. However, if you are following a training plan and already know what amounts you need over a period of time, then a pack of pre-dosed capsules may be more useful.

Taking the capsules is easier and faster because they can be consumed directly and do not have to be mixed into a shake first. However, they are also more expensive in comparison, but make it easier to manage the sometimes "expensive training plans" that contain other supplements besides D-AA. For those who are willing to spend a little more money, the ampoules with D-AA and other amino acids and vitamins are recommended. Here, the athlete really gets everything he or she needs for successful training in already measured form for quick intake.

Other ingredients

Here you often come across additives such as tribulus terrestris extract or maca extract. Especially the saponins contained in them are said to have a positive effect on muscle growth and potency, but scientific evidence for this is lacking. Tribulus-Terrestris, also called earth spine nut, is a widespread plant whose secondary plant substances such as saponins are also found in many other (vegetable) plants such as beans, asparagus and soy. (4)

Ingredients such as Tribulus Terrestris and Maca have no proven effect on muscle growth.

The maca plant (Lepidium meyenii Walp.) belongs to the cruciferous family and comes from the high altitudes of the Peruvian Andes. For some years now, products containing maca have been offered in Germany as food supplements in the trade, especially via the internet.

Some of the capsules, dragées and tablets are advertised as increasing potency, fertility and libido, and athletes are promised performance gains. The Federal Institute for Risk Assessment (BfR) has evaluated these products and had scientific studies carried out. Animal experiments did show some effects on the sex organs and the hormone balance of animals, but it cannot be deduced that there are similar effects in humans.

Moreover, the data basis of the existing studies is too small to derive an effect for humans. Therefore, the consumption of Maca root is considered safe and free of side effects.

Guide: Frequently asked questions about D-aspartic acid answered in detail

In order to inform you comprehensively about the effectiveness of aspartic acid and to give you an understanding of the current state of science, we have summarised all the important information in the following sections.

What is D-aspartic acid and how does it work?

Effect on the testosterone balance of male animals

Endogenous D-AA acts as a neurotransmitter (NMDA, N-methyl-D-aspartate) (8) in the neuroendocrine system via a cascade with FSH (follicle stimulating hormone), LH (luteinising hormone) and HGH (a growth hormone) on the testes. D-AA participates in the testes via mRNA synthesis in the provision of the protein complex known as STAR, which in turn regulates the production of testosterone. (6)


The right workout always depends on you (Image source: Anastase Maragos //

Scientists were able to prove that, at least in the Leydig cells of rats, D-aspartic acid leads to an increase in testosterone production.

Effect of D-aspartic acid on the brain

Recent studies have shown that D-AA as a neurotransmitter (7)can also have an effect on the development of the nervous system.


The effect of D-aspartic acid on neurons in the brain (Image source: Robina Weermeijer//

D-aspartic acid can thus have an effect on the activity of the synapses via the regulation of the transport of messenger substances and thus improve important brain functions such as memory and concentration. (10)

Effect of D-aspartic acid on the reproductive potential of women

For women, D-aspartic acid plays an important role not only in sex life but also in reproduction. A study has shown that D-AA is a physiological component in the follicular fluid that decreases with age and influences the reproductive potential of women.(9)


Women should also consider taking D-aspartic acid if they have unknown symptoms before or during pregnancy (Image source: Andrea Bertozzini //

Therefore, it may be beneficial for menopausal women, as well as those of productive age, if it promotes reproductive potential and increases libido.

When and for whom is it useful to take D-aspartic acid?

Taking D-aspartic acid certainly offers many benefits. For some of us, however, taking D-aspartic acid can also bring disadvantages.

You can take D-AA without hesitation if you:

  • Are a man older than 21 and have problems with low testosterone levels
  • You are looking for an easy way to build muscle mass through the anabolic effects of testosterone
  • You want to rev up your libido over a short period of time

You should not take D-AA if you:

  • You are a woman who has not spoken to a doctor before taking the product
  • You are younger than 21 and have elevated testosterone levels
  • You have generally elevated testosterone or estrogen levels

What foods contain D-aspartic acid?

D-aspartic acid is synthetically manufactured and is therefore not found in any food. To take D-aspartic acid, you should buy the manufactured powder or capsules from a fitness nutrition shop or on the internet. The situation is different with L-aspartic acid. As the name suggests, it is found in high concentrations in asparagus and soya. It is also a component of many of the body's own proteins and is normally present in the body as a hermaphrodite ion.


More weights= More muscles? This is where D-aspartic acid can help (Image source: Delaney Van //

What types of D-aspartic acid are there?

D-aspartic acid should be taken at training times with a dose of 3 grams always taken before training. In weeks without training, a smaller dose can be taken in the morning and evening throughout the day. Powder, capsules and ampoules are suitable for this purpose, whereby the ampoules are the easiest and quickest to take, the powder the most time-consuming.

Type Description
D-AA powder Is the cheapest variant and can be dosed according to one's own needs. The powder should be dissolved in a shake before consumption.
D-AA capsules The capsules offer the advantage that they can be consumed directly and the dosage is specified by the manufacturer. They are perfect for quickly achieving the desired effects shortly before or during training.
D-AA ampoules Here you get an amino acid cocktail in liquid form for a hefty price. It can also be consumed directly and offers, in addition to D-AA, several other useful amino acids that can improve the training effect.

In the end, it is always a question of personal taste which type of intake one prefers. Competitive athletes who want to achieve even more peak performance during training are best advised to take an ampoule, while recreational athletes who appreciate not only the muscle gain but also the effects on the libido are best advised to take D-AA as a powder stirred into a shake.

D-Aspartic acid powder

D-aspartic acid powder is the cheapest and most versatile way to take D-aspartic acid. It can be used either in a shake or as a baking or cooking ingredient. Of course, the powder must first be dissolved in a liquid before it can be enjoyed, but then it is suitable for many types of food intake (solid or liquid).

D-aspartic acid capsules

If you don't like the taste of powder and liquid and don't have problems swallowing capsules, then D-aspartic acid capsules are the best solution for you. Since the capsules are sealed and the capsule itself is tasteless, you can quickly take D-aspartic acid even during training.

How should D-aspartic acid be dosed?

At the beginning of the D-AA cure you should start with 3 grams per day and keep this up for 2-3 weeks in a row. After that, you should not take any D-AA for at least 1-2 weeks. It is best to take D-AA in a shake or with a drink. On training days, take it about 45 minutes before training, on non-training days in the morning and in the evening.

D-aspartic acid preparations should only be taken for a short period of 1-2 weeks.

You should not eat before or after taking D-AA. The recommended dosage is on an empty stomach, i.e. before breakfast and after supper. After the first 2-3 week cycle, you can then increase the dose, depending on how you tolerate the D-AA.

20 grams per day is the highest dosage that is still tolerated. Most successful athletes take between 5-10 grams of D-AA per day(3)

What alternatives are there to D-aspartic acid?

Similar effects can be achieved with over-the-counter L-arginine, for example. If you want to achieve even stronger effects with a testosterone cure, you should consult a doctor to rule out possible prostate carcinomas. With a prescription-only pure testosterone preparation such as Testogel, for example, even greater muscle gains can be achieved more quickly, but if used incorrectly, equally great problems can arise.

What is the connection between D-aspartic acid and testosterone?

The effects of D-AA on testosterone levels in humans cannot be scientifically proven, as the few studies available did not have a significant number of test subjects. However, effects on testosterone levels in male animals could be proven. (2)

Image source of cover picture: 112394091/

References (10)

1. D-Asparaginsäure; eine essentielle Aminosäure mit einer wichtigen neuroendokrinen Rolle

2. Die Wirkung von D-Asparaginsäure auf die Testosteronproduktion in Menschen- und Rattenhoden

3. Die richtige Anwendung von D-Asparaginsäure

4. Wirkung von Tribulus-Terrestris/ Erdsternchen in der Anwendung als Supplement beim Fitnesstraining

5. Untersuchung der Wirkung von D-Asparaginsäure auf Testosteronwerte im Blut

6. Untersuchung der Wirkung von D-Asparaginsäure auf die Testosteronproduktion in den Leydig Zellen des Hoden bei Ratten

7. D-Asparagin als neuer endogener Neurotransmitter

8. Der Effekt von D-Asparaginsäure auf die Hormone LH, AMS, GABA und Dopamin

9. Wirkung von D-Asparaginsäure auf die Follikularflüssigkeit vor dem Eisprung

10. Neuronale D-Asparaginsäure reguliert die Neuronensynthese im Erwachsenen Gehirn

Scientific Review: d-Aspartic acid: An endogenous amino acid with an important neuroendocrine role
D-Asparaginsäure; eine essentielle Aminosäure mit einer wichtigen neuroendokrinen Rolle
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Controlled Clinical Trial: The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats
Die Wirkung von D-Asparaginsäure auf die Testosteronproduktion in Menschen- und Rattenhoden
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General Review: The Ultimate D-Aspartic Acid (DAA) Guide: Benefits, Dosages & FAQ
Die richtige Anwendung von D-Asparaginsäure
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General Review: Testosteron-Booster Tribulus – Was kann das Erdsternchen wirklich?
Wirkung von Tribulus-Terrestris/ Erdsternchen in der Anwendung als Supplement beim Fitnesstraining
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Scientific Review: The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review
Untersuchung der Wirkung von D-Asparaginsäure auf Testosteronwerte im Blut
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Scientific Review: Stimulation of steroidogenic acute regulatory protein (StAR) gene expression by D-aspartate in rat Leydig cells
Untersuchung der Wirkung von D-Asparaginsäure auf die Testosteronproduktion in den Leydig Zellen des Hoden bei Ratten
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Scientific Review: D-Aspartic acid is a novel endogenous neurotransmitter
D-Asparagin als neuer endogener Neurotransmitter
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Scientific Review: The effect of D-aspartate on luteinizing hormone-releasing hormone, alpha-melanocyte-stimulating hormone, GABA and dopamine release
Der Effekt von D-Asparaginsäure auf die Hormone LH, AMS, GABA und Dopamin
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Scientific Review: Reproductive implication of D-aspartic acid in human pre-ovulatory follicular fluid
Wirkung von D-Asparaginsäure auf die Follikularflüssigkeit vor dem Eisprung
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Research Article: Aspartate racemase, generating neuronal D-aspartate, regulates adult neurogenesis
Neuronale D-Asparaginsäure reguliert die Neuronensynthese im Erwachsenen Gehirn
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