D-Aspartic Acid (DAA) is naturally-occurring amino acid in humans and numerous foods, albeit in significantly lower quantities than its isomer LAA (L-aspartic acid). Nevertheless, DAA plays crucial roles in human neuroendocrinology, particularly with regard to the manufacturing of androgens and various peptide hormones.
In the past five years, D-aspartic acid supplements have increased substantially, due to the prospect of enhancing physical/athletic capacity. As research and anecdotal evidence have shown, DAA can certainly raise endogenous (i.e. "your own") levels of hormones such as testosterone, growth hormone (GH), and insulin-like growth factor 1 (IGF-1). Read on to learn why this is highly beneficial for physical performance and overall wellness.
Testosterone, Growth Hormone, & IGF-1
You're likely well aware that testosterone is the main sex hormone (androgen) in males. The synthesis of testosterone is modulated by the highly sensitive interplay between the pituitary gland, hypothalamus, liver, and gonads/testes (called the hypothalamic–pituitary–gonadal axis (HPG axis). Fun fact: this is where our company gets its name.
When serum levels of free testosterone drop significantly enough, the hypothalamus creates gonadotropin-releasing hormone (GnRH); GnRH signals the pituitary gland to secrete luteinizing hormone (LH); LH signals the testes to manufacture testosterone. Notice how these hormones ultimately act as a cascade.
Furthermore, IGF-1 and GF secretion are likewise controlled by this exact same HPG axis. Your hypothalamus produces growth hormone-releasing hormone (GHRH), which then tells the pituitary gland to secrete GH in pulses. GH then influences your liver to synthesize IGF-1.
Now that you have at least an elementary understanding of the HPG axis, let's examine how DAA acts in males.
D-Aspartic Acid's Physiology in Men
Several studies demonstrate that DAA interacts with the hypothalamus to promote the secretion of GnRH and GHRH, which act downstream to synthesize testosterone, GH, and IGF-1. [1,2,3]
Another promising finding is that DAA can also stimulate the creation of thyroid hormones (particularly T3).  Researchers postulate that this arises from the oxidation of DAA by the thyroid gland to hydrogen peroxide, an important precursor for the synthesis of tyrosyl compounds (which are needed for thyroid hormone synthesis).
Note that animal data doesn't necessarily unequivocally translate to how substances will act in human beings. In the case of DAA, human studies remain limited but nonetheless promising. 
Anecdotal proof of D-Aspartic Acid's benefits is highly favorable, so more peer-reviewed human studies are likely to happen. It's also important to note that certain factors, such as age, genetics, diet, endocrine health, etc. can alter how DAA acts in your body. As such, some people will need a larger (or smaller) dose of DAA to achieve the same benefit as someone else.
Benefits of Supplementing with D-Aspartic Acid
Benefits of DAA (which can be found in Hypertest XTR) may be slightly variable from one person to the next and experimentation with dose, frequency, and period of use will likely be necessary. Most individuals can expect the following after using DAA for at least three weeks:
- Elevations of serum levels of anabolic and fat-burning hormones/peptides, which all have favorable implications for your athletic/physical performance, well-being, and sex drive
- Enhanced thyroid hormones production - raising levels of thyroid hormones helps increase your metabolism
Chances are you're thinking, "There are only two reasons to use DAA?" Well, in reality, these reasons are major benefits when you consider that hormones like testosterone and T3 act systemically.
Moreover, IGF-1, GH, and testosterone each have a positive impact on recovery from intense exercise, as well as improving muscle hypertrophy, increasing strength, enhancing sex drive, and myriad other therapeutic properties for active people.
Are there Any Risks from Using D-Aspartic Acid?
One of the primary advantages of DAA is that it presents an all-natural method of increasing anabolic and fat-burning hormones (which is much safer than using anabolic steroids or prohormones).
You might produce slightly more estrogen while using DAA, but it must be kept in mind that negative effects will be negligible if you're cycling your usage of DAA as suggested herein. Offset this effect by stacking Hypertest XTR with Myodex.
Who is D-Aspartic Acid Beneficial For?
Most active males and gym-goers will benefit by using DAA (found in Hypertest XTR) due to its systemic actions.
The best candidates for DAA use are:
- Males who are 21+ years old
- Gym-goers and athletes who desire a natural means of elevating anabolic hormone production
- Those with low sex drive and feel their inhibited recovery from exercise is impeding progress
- Older males who want a better sense of vitality and energy throughout the day
Recommended D-Aspartic Acid (HyperTest XTR) Usage
- Start with 3 g per day (one dose of HyperTest XTR) and assess your tolerance/results after one cycle (i.e. 4 weeks of use)
- We recommend using DAA for 6-to-8 weeks at a time, followed by 1 to 2 weeks off
Q: Should I use an aromatase inhibitor when I take DAA?
A: Yes, we recommend stacking Myodex with Hypertest XTR for proper testosterone-estrogen modulation.
Q: Does DAA harm my endocrine system?
A: No, unlike prohormones and anabolic steroids, DAA works to bolster your natural endocrine function. You do not need any "post-cycle therapy."
- D'Aniello, A. (2007). D-Aspartic acid: an endogenous amino acid with an important neuroendocrine role.Brain research reviews, 53(2), 215-234.
- D’ANIELLO, A. et. al. (2000). Occurrence of D-aspartic acid and N-methyl-D-aspartic acid in rat neuroendocrine tissues and their role in the modulation of luteinizing hormone and growth hormone release.The FASEB Journal, 14(5), 699-714.
- Di Fiore, M. M., Assisi, L., Botte, V., & D'Aniello, A. (1998). D-Aspartic acid is implicated in the control of testosterone production by the vertebrate gonad. Studies on the female green frog, Rana esculenta.Journal of endocrinology,157(2), 199-207.
- Willoughby, D. S., & Leutholtz, B. (2013). 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), 803-810.
- Topo, E., Fisher, G., Sorricelli, A., Errico, F., Usiello, A., & D'Aniello, A. (2010). Thyroid Hormones and D‐Aspartic Acid, D‐Aspartate Oxidase, D‐Aspartate Racemase, H2O2, and ROS in Rats and Mice. Chemistry & biodiversity, 7(6), 1467-1478.