Does D-aspartic Acid Increase Testosterone Levels? (What the Studies Reveal)

  • Studies prove that d-aspartic acid does raise testosterone levels
  • It is particularly powerful as a libido booster and to increase fertility
  • Dosage should be capped at 3000mg per day

D-aspartic acid is a non-essential amino acid. It is an isomer of L-aspartic acid, which is one of the 23 amino acids that synthesize proteins in our body.

Amino acids are molecules that perform various functions in the body. They are the building blocks of protein and certain neurotransmitters and hormones.

Each amino acid can occur in two forms. Aspartic acid can be found as D-aspartic acid or L-aspartic acid. These two forms have the same chemical formula, but the molecular structure is a mirror image of each other.

L-aspartic acid is produced both in nature and by our bodies, it is used to build proteins. On the other hand, its isomer, DAA aid in making and releasing hormones.

D-aspartic can increase the release of hormones in the brain that can, in turn, lead to testosterone production. It is believed to help both production and release of testosterone, and for this reason, it is popular as a testosterone boosting supplement.

How D-aspartic acid helps boost testosterone

When DAA acid accumulates in the frontal region of the hypothalamus, it signals the hypothalamus to release gonadotropin-releasing hormone (GnRH). This causes an increase in secretion of both growth hormone-releasing hormone (GHRH) and prolactin release factors (PRF).

These three hormones then signal the pituitary gland to release more of human growth hormone (HGH) and luteinizing hormone (LH). Luteinizing hormone (LH) travels to the testes and stimulates the production of testosterone inside the Leydig cells within testes.

Research on effectiveness of D-aspartic acid as a testosterone booster

Several studies have been conducted to understand the efficacy of D-aspartic acid on testosterone levels in both animals and humans. Lets us check out what some of these studies found out.


The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats

In this study, 23 men were given sodium D-aspartic acid daily for 12 days, and another group of 20 men was given a placebo. In the animal study, a group of 10 rats were given either sodium D-aspartic acid or a placebo for 12 days. At the end of the study, it was found:

·       In rats and humans, sodium D-aspartate induces an increase of Luteinizing Hormone and testosterone release

·       Sodium D-aspartate enhances the release and synthesis of Luteinizing Hormone through the involvement of cyclic guanosine monophosphate (cGMP)


d-Aspartic acid supplementation combined with 28 days of heavy resistance training does not affect body composition, muscle strength, and serum hormones associated with the hypothalamo-pituitary-gonadal axis in resistance-trained men.

In this study, 20 resistance trained men ages 18-29 resistance trained four times a week and ingested either 3gm of placebo or D-aspartic acid for 28 days. At the end of the study period, scientists noted that in the placebo group there was:

  • No change in body composition
  • No change in testosterone or estrogen levels


Three and six grams supplementation of d-aspartic acid in resistance trained men

The study involved 24 men with a minimum of two years’ experience in resistance training. The participants were divided into three groups, one group received 3gm d aspartic acid, the second received 6 gm aspartic acid, and the third was given a placebo. They trained four days a week and consumed the supplement each morning. The study revealed:

  • a daily dose of 6 grams of d-aspartic acid decreased free testosterone and total testosterone levels
  • 3 grams of d-aspartic acid did not affect the testosterone markers


D-Aspartate, a Key Element for the Improvement of Sperm Quality

In this study, thirty men with oligo-asthenozoospermia and thirty men with asthenozoospermia were given a 2.66 grams daily dose of sodium d-aspartate for 90 days. It was found that:

  • D-aspartate supplementation significantly increased the motility and concentration of spermatozoa
  • Increase in serum testosterone levels

Aspartic acid in treating male infertility.

Study: A supplement containing 80% D-Aspartic acid (1.6g) and 20% L-Aspartic acid (0.4g) was given to men between the ages of 25-40. The men were to take this supplement, daily, in half a glass of water or juice, after lunch for 20 consecutive days. Measurements were then taken on testosterone and luteinizing hormone levels, both of which are crucial to reproduction.

Results: The experiment found increases in testosterone and luteinizing hormone levels in 8 out of the 10 men. In addition, the number of motile sperms in these individuals increased by 51%

Conclusion: D-aspartic acid and L-aspartic acid can effectively increase the levels of testosterone when taken for 20 days at a dose of 2g/day.

Source :


Aspartic acid induces the release of testosterone and luteinizing hormones.

Study: A treatment study was conducted on 23 men enrolled in an infertility program. These men were given 3.2g of D-Aspartate for 12 days, and blood samples were collected for hormonal testing between treatments, as well as after. This experiment was simultaneously conducted on rats.

Results: The experiment saw a significant increase in levels of luteinizing and testosterone levels in 20 out of 23 men. These levels remained high after six days of treatment and did not decline for three days after the treatment ended. Amongst the rats, the levels of testosterone were found to be higher than the levels of luteinizing hormones.

Conclusion: A 12-day D-Aspartate treatment led to a significant increase in testosterone levels.


D-aspartic acid plays a crucial role in initiating synthesis of testosterone in mallard birds.

Study: D-Aspartic Acid has been found to be effective amongst birds. A study conducted by the University of Naples reported findings on the role of this amino acid in testosterone production amongst mallard birds.

Results: The authors quantified the natural D-Aspartic acid levels in the testosterone producing cells (Leydig cells) and observed that high levels coincided with high levels of testosterone.

Conclusion: D-Aspartic acid has a positive role in initiation and production of testosterone amongst mallard birds.


D-aspartic acid influences testosterone production amongst wild pigs (Boar).

Study: A study was conducted by Lamanna and co on wild pigs, a mammal with a high number of testosterone producing cells, otherwise known as Leydig cells. Using the highly sophisticated immunohistochemistry technique, the level of natural D-Aspartic acid and testosterone in these cells were quantified. This was done by culturing the cells in the laboratory.

Result: High levels of testosterone were found in tissues where there was an abundant level of D-Aspartic acid.

Conclusion: D-Aspartic acid induces the production of testosterone in wild pigs.


D-Aspartic acid increases reproductive hormone secretions in green frog.

Study: During a study conducted on green frogs, F Raucci and co discovered that D-Aspartic acid levels increased during the reproductive phase, modulating the production of testosterone. The frogs were given D-Aspartic acid injections and subsequently quantified the levels of testosterone. An increase in testosterone levels was observed, although a decline was noted after 18 hours.

Result: Among frogs, D-Aspartic acid positively modulates the production of testosterone. Injecting D-Aspartic acid increases the level of this amino acid in testes, which was followed by an increase in testosterone levels.

Conclusion: D-Aspartic acid increases testosterone production levels amongst green frogs.


A molecular study on rats and the effects of D-Aspartate on their testosterone levels.

Study: Nagata and co administered rats with D-Aspartate to study its molecular targets. In particular, the genes/proteins that were up-regulated.

Results: This was the first report to show a molecular target that eventually led to an increase in testosterone levels. A protein called “StAR” is activated by D-Aspartic acid, leading to increased secretions of testosterone from Leydig cells (testosterone producing cells).

Conclusion: D-Aspartic acid induces the release of testosterone by activating the StAR protein.


Increased testosterone production by laboratory cultured cells from rat testes.

Study: The Leydig cells (testosterone producing cells) from rat testis were cultured in petri dishes in the presence of D-Aspartic acid and other amino acids. The levels of D-Aspartic acid and testosterone in these cells were quantified.

Result: There was a significant increase in the levels of testosterone and D-Aspartic acid in cells grown with D-Aspartic acids. Other amino acids used as supplements failed to produce any impact on levels of testosterone and D-Aspartic acid.

Conclusion: An increase in testosterone levels was found amongst rats when their Leydig cells were cultured in the presence of D-Aspartic acid.


D-Aspartate increases production of testosterone in rat testes.

Study: D’Aniello and co conducted a study to determine the role D-Aspartic acid plays in the production of testosterone in rat testes. Rats were injected with D-Aspartic acid and the levels of reproductive hormones like testosterone, luteinizing hormones and progesterone were estimated along with D-Aspartic acid level. Simultaneously, the authors studied the effect of adding D-Aspartic acid to the dissected rats and estimated the uptake.

Results: The authors found that D-Aspartate accumulated in testes and induced the production of testosterone by approximately 4 times higher than the normal base levels.

Conclusion: D-Aspartic acid leads to increased production of testosterone in rat testes.


D-aspartic acid induces the production of steroids in frog brain.

Study: In two separate studies, Maria D Foire’s group has proven that enzymatic targets triggered by D-Aspartic acid led to the production and regulation of estradiol (steroid) in frog brains. The frogs were administered with D-Aspartic acid before and after the reproductive phase and levels of proteins like P450 aromatase and estradiol (which were essential for fertility) were estimated.

Result: D-Aspartic acid increased estradiol levels exclusively in the reproductive phase via the action of enzyme P450 aromatase.

Conclusion: D-Aspartic acid also modulates steroids like estradiol.


Possible side effects of d-aspartic acid supplementation

D-aspartic acid supplementation can cause a variety of side effects, which may include:

  • Higher estrogen levels that may cause symptoms such as:
    • Gynecomastia
    • Bloating
    • Prostate problems
    • Low libido
  • Higher dihydrotestosterone that can cause acne and hair loss
  • Reduced production of Gamma-aminobutyric acid (GABA), a neurotransmitter that helps transmit messages between the brain and the nervous system. This can cause fatigue and depression.

You should avoid using it if you are:

  • Under 21 years of age
  • Having increased testosterone levels
  • Having excess levels of estrogen or DHT
  • Suffering from hyperthyroidism
  • Suffering from depression or other mental health problems


How Much D-Apartic Acid to Take

D-aspartic acid is certainly effective but how much should you take to make sure that it does the job while still keeping you safe? For the answer, I turned to many of the current scientific studies that exist and I thought might help.

In one study I looked at, 1.6g of it was administered daily to men between the ages of 25 to 40 for 20 consecutive days. Testosterone levels and luteinizing hormones increased in eight out of ten of those men. In addition, the sperm count of those men increased on average by 51%, showing a significant increase.

In another study, as much as 3.2g of it was given to 23 men who were enrolled in an infertility program for 12 days straight. 20 out of the 23 men saw a significant increase in free testosterone levels.

Based on these two studies plus others I have read, anything under 3g of DAA taken daily will be safe. For it to be effective you will want to make sure the dosage exceeds about 1.5g per day. So dosing with between 1.5g – 3g of DAA daily should be safe and effective in boosting testosterone levels.

Best Time to Take D Aspartic Acid

There really is no best time to take d-aspartic acid. A common method is to dose throughout the day, so for example you might dose 4 times throughout the day with food so as to keep a consistent rate of acid in your body. Just make sure the combined dosage of those four servings does not exceed three grams.

In the first study I referenced about where 1.6g of it was administered daily, the full dosage was just taken once a day after lunch. This shows that one dosage will probably be just as effective, it will certainly be more convenient so it’s really up to your personal preference. One thing that you should definitely do is always take d-aspartic with food and never on an empty stomach. Apart from that, it doesn’t really matter what time of the day it is. If in doubt, go with lunch.

How to Take D Aspartic Acid – Powder or Capsule?

It is usually consumed either in powder form or as a capsule, either will work just fine. The powder form can be mixed with water or juice so you can mask the taste (which isn’t great) and have it with your drink alongside your lunch. But the capsule works great as well. Often people will take testosterone boosters, which mix together DAA with other natural ingredients, these usually come in the form of a capsule and can be quite convenient. I would just take whatever works best with you, I like the capsules as they are quick and easy to take.

The Bottom Line

D-aspartic acid does seem to boost testosterone levels. It is particularly good for people battling infertility due to low sperm count and motility. However, research also shows that it does not work on resistance trained men. If you are into intense workouts and looking to boost your testosterone, stamina or muscle mass, this may not be the best thing for you.

Based on the lack of side effects and its overall effectiveness, d-aspartic acid is actually the no.1 ingredient that I look for in a testosterone supplement.