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D-Aspartic Acid: The Ultimate Guide

If your goal is to build muscle, gain strength, and lose a little fat in the process, then it should come as no surprise that training and diet is key.

However, once your workout regime and eating habits are in check, there is absolutely no reason you should not look towards supplements for an extra boost.

And one supplement that has been increasing in popularity over the last decade is D-Aspartic acid (or DAA for short).

What is D-Aspartic acid?

DAA is a specific type of amino acid found in small amounts throughout your body.

While it plays a hand in numerous physiological processes, it appears to be particularly important when it comes to your neuroendocrine system -- where it promotes the production of growth factors and anabolic hormones.

In fact, evidence suggests that DAA triggers the synthesis and secretion of insulin-like growth factor 1 (or IGF-1, for short), human growth hormone, and testosterone. All of which are incredibly important when it comes to training related outcomes (but more on that later).

Now, it is important to note that while DAA can be found within your body, it is only synthesised in small amounts, suggesting that consuming extra may provide some additional benefits.

With this in mind, you can obtain small amounts of DAA in foods like milk, cheese, yoghurt, eggs, red meat, poultry, and fish -- however, when I small, I really do mean small -- like, negligible amounts.

Which is why supplementing with DAA is a much more feasible option.

What are the benefits of D-aspartic acid?

I have already alluded to the fact that DAA has important implications for your neuroendocrine system -- which is also where DAA supplements provide their benefits.

1.    D-aspartic acid boosts testosterone

When I first introduced you to DAA, I outlined its role regarding testosterone production. As a result, it makes sense from a mechanistic perspective that its supplementation would subsequently boost testosterone -- and there is research suggesting that this is the case.

In fact, multiple studies have shown that when men supplement with DAA for 12 day straight, they will see an increase in their free testosterone levels (a measure of how much testosterone is in your blood) [1, 2].

However, it is important to note that these studies were conducted in men who already had been diagnosed with low testosterone. Additional research on DAA supplements in men with naturally higher testosterone levels was shown to cause no change [3].

This suggests that DAA has the potential to boost testosterone if your levels are on the lower side. And if they are on the higher side, then it may not have any effect.

2.    D-aspartic acid makes you more anabolic

When you are talking about hormones, you can very loosely organise them into two categories -- being anabolic and catabolic.

Testosterone is an extremely anabolic hormone because it promotes the development of new tissue. This can include muscle tissue, connective tissue (ligaments and tendons), bone tissue, and even organ tissue.

For you regular gym goers, testosterone is great because it facilitates muscle growth.

Conversely, catabolic hormones break down your body's tissues for energy. This means that if your goal is to build muscle, you want to keep catabolic hormones as low as you possibly can.

Cortisone is a highly catabolic hormone because it increases inflammation and promotes the breakdown of protein in your body. Similarly, while estrogen does not directly break down tissue, it can mitigate the action of testosterone -- and could therefore also be considered more catabolic in nature.

Fortunately, some research has shown that supplementing with DAA can reduce the section of both estrogen and cortisone [4].

This combination of factors may therefore create a more anabolic environment in your body, facilitating muscle growth -- however there are currently no long term studies demonstrating this with certainty.

3.    D-aspartic acid enhances your performance

Lastly, supplementing with DAA may also have the capacity to boost your gym performance.

When compared to a placebo, DAA supplements have been shown to cause significant improvements in muscle strength and power immediately after consumption [5, 6]. While these studies were only over a short timeframe, they do indicate that DAA may increase your performance in the gym.

If this improved performance leads to you putting more weight on the bar or performing repetitions, then there is reason to believe that it could also lead to increases in muscle growth and strength over time.

Again, more long term training studies are needed to demonstrate this with certainty, but early signs are promising.

How to supplement D-aspartic acid

Taking the above into consideration, it appears that supplementing with DAA could have some unique benefits with regards to both muscle growth and improvements in strength -- but how should you take it?

Most of the research demonstrating the positive effects of DAA supplementation has used dosages of 3 grams per day. They also tend to “cycle off” DAA every two weeks to ensure your body does not build up a tolerance.

This means that your best bet is to take 3 grams of DAA per day (any time of the day is fine) for two weeks, followed by 5-6 days of no supplementation. You can then repeat this cycle as often as you like.

Can you take too much D-aspartic acid?

It is also important to note that when it comes to DAA, more is not better. One of the research studies mentioned above also explored the differences between supplementing with 3 and 6 grams of DAA per day [6] -- and the results were interesting to say the least.

Because the participants were healthy young males, their testosterone levels were relatively high. As a result, the group taking 3 grams of DAA per day did not see any change.

But the 6 gram group?

Well their testosterone levels actually decreased.

It was thought that the higher dose of DAA may have impacted upon the hormonal system in a negative manner, or even accumulated in the testes -- both of which would have caused a disruption to testosterone production.

All of which indicates that you should not take more than 3 grams of DAA per day.

D-aspartic acid side effects

DAA supplements have been shown to be extremely safe. In fact, research would indicate that if you are taking your DAA supplement recommended dosages, and cycling off at regular intervals, you will be very unlikely to have any serious side effects.

However, we should note that some individual participants have reported some small side effects during supplementation, including:

  • Slight irritability
  • More regular headaches
  • Mild anxiousness
  • Mood swings

Conversely, some participants also reported experiencing increased libido and heightened energy levels -- suggesting that these responses are rare and highly individual.

Key Points

D-aspartic acid has been shown to increase testosterone production, while simultaneously reducing cortisone and estrogen secretion. While this effect is more pronounced in individuals with low testosterone levels, it does suggest the capacity to create an anabolic environment that could increase muscle growth.

And when this is combined with observed improvements in strength and power, the benefits of D-aspartic acid become apparent.

It is important to remember that if you choose to supplement with DAA, sticking to the recommended dosage of 3 grams per day is paramount, as too much can have negative effects.



  1. Topo, Enza, et al. "The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats." Reproductive Biology and Endocrinology 7.1 (2009): 120.
  2. D’Aniello, Gemma, et al. "d-Aspartate, a key element for the improvement of sperm quality." Advances in Sexual Medicine 2.04 (2012): 45.
  3. Willoughby, Darryn S., and Brian Leutholtz. "D-Aspartic acid supplementation combined with 28 days of heavy resistance training has no effect on body composition, muscle strength, and serum hormones associated with the hypothalamo-pituitary-gonadal axis in resistance-trained men." Nutrition research 33.10 (2013): 803-810.
  4. Falcone, Paul H., et al. "Consumption of a testosterone-boosting supplement is safe and lowers estrogen and cortisol levels." Medicine & Science in Sports & Exercise 47.5S (2015): 338.
  5. LaMacchia, Zach, et al. "Acute D-Aspartic Acid Supplementation does not have an Effect on Serum Testosterone but does have an Effect on Strength Measures in College Aged Male Athletes." European Journal of Sports & Exercise Science 5.3 (2017): 34-41.
  6. Melville, Geoffrey William. Effects of d-aspartic acid on testosterone and training outcomes in a resistance trained population: findings from an acute dosing study, and a three-month training study. Dissertation. Western Sydney University (Australia), 2016.
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