- All amino acids have three of the same groups bonded to a central carbon: a “COOH” group, an “NH3” group and a hydrogen. They also each have a distinct sidechain; aspartic acid’s is “CH2COOH.” The reason for the “L” in front of aspartic acid’s name is that technically, aspartic acid — like most of the other amino acids — is asymmetric, and exists in two mirror-image forms. Only one form, denoted by the L, occurs naturally in proteins, however.
- Most testosterone boosting supplements include D-aspartic acid, often listed as DAA or D-asp, as the first ingredient. There is some debate as to whether or not D-aspartic acid is effective. D-aspartic acid is not intended to be used by people under 21 years of age. Always consult with your physician before using any supplements.
- All amino acids, except glycine, that are used by the human body for protein synthesis have two nearly identical forms, noted as L- or D-. These designations refer to how parts of the molecule react under an optical light. With regards to protein synthesis and muscle growth, only the L- forms are used for this process. The D- form of the amino acids are also found within the human body and can be used in a variety of processes as well.
- Like all amino acids, your body can use aspartic acid to provide your cells with energy; the cells burn it to generate ATP, or adenosine triphosphate, which is a cellular energy currency. While aspartic acid is useful, it’s not essential in the human diet — your body makes it from a molecule called oxaloacetate, which you produce any time you metabolize fuel, regardless of whether the fuel is carbohydrate, protein or fat.
- Recommended Usage: Long-term studies have not been performed using D-aspartic acid. Most manufacturers of products containing D-aspartic acid recommend using the product for periods of 4 to 12 weeks followed by a period of cessation from the product lasing 2 to 4 weeks. Always read the label on the supplement you are taking and use that recommendation accordingly. Current recommendations based on “Reproductive Biology and Endocrinology” suggest using 3.12 g per day.
- There are a few things your body can do with aspartic acid that no other amino can perform. It stimulates a neural receptor called the NMDA receptor, which plays a role in memory and cognition. You can also use it to make several other amino acids, making it useful for preventing amino acid deficiencies. Finally, it has an important role in gluconeogenesis, which is the process of making glucose, or sugar, when your supply is low.
- Aspartic Acid and Testosterone: With regards to testosterone, D-aspartic acid is utilized, not the L- form. A study at the University of Naples using birds demonstrated that D-aspartic acid reacts within the brain to release luteinizing hormone, or LH. LH then travels to the testicles where it enters the specialized cells, or Leydig cells, which have the function of creating testosterone. Articles published by “Brain Research Reviews” concur with the proposed action of D-aspartic acid and its effects on testosterone.
- D-Aspartic Acid and Humans: Animal studies showing the effectiveness are great, but studies using those same supplements on humans are inconclusive. There are few studies performed using D-aspartic acid and humans. One study in “Reproductive Biology and Endocrinology” showed that males supplemented with 3.12 g of D-aspartic acid for 12 days experienced an increase in their free testosterone by approximately 40 percent. After three days of no use, their free testosterone levels dropped by about 10 percent.
aspartic acid; Asparagic acid; L-aspartate; Asparaginic acid; (2S)-Aspartic acid; Aspartate;
Source: Hendrickson, Kirstin, “What Is L-Aspartic Acid & How Does It Help the Body?”, 04 APR 2011, www.livestrong.com/article/414565-what-is-l-aspartic-acid-how-does-it-help-the-body/
Source: Stark, Matt; “The Effects of Aspartic Acid on Testosterone”, 16 Aug 2013, www.livestrong.com/article/474566-the-effects-of-aspartic-acid-on-testosterone/