Aspartic acid information
June 1 2016

It's difficult to find human studies with aspartic acid supplements.

Hormone release influence
Thanks for a great wealth of information of natural products. Have you any information about a natural LH releasing product called D aspartic acid? I was told by a health food store employee it works like Clomid to natually release LH to stimulate testosterone production. I have heard of clomid as my Endicrinologist told me it's an option for Testosterone replacement. I am a 38 year old male and would appreciate your professional opinion about this product as a safe and natural testosterone replacement.
   One small study with 20 men for a period of 12 days showed some testosterone enhancement but whether benefits continue in the long run is not easy to know.

Reprod Biol Endocrinol. 2009. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats.
D-aspartic acid is an amino acid present in neuroendocrine tissues of invertebrates and vertebrates, including rats and humans. Here we investigated the effect of this amino acid on the release of LH and testosterone in the serum of humans and rats. Furthermore, we investigated the role of D-aspartate in the synthesis of LH and testosterone in the pituitary and testes of rats, and the molecular mechanisms by which this amino acid triggers its action. For humans: A group of 23 men were given a daily dose of D-aspartate (DADAVIT) for 12 days, whereas another group of 20 men were given a placebo. For rats: A group of 10 rats drank a solution of either 20 mM D-aspartate or a placebo for 12 days. Then LH and testosterone accumulation was determined in the serum and D-aspartate accumulation in tissues. The effects of D-aspartate on the synthesis of LH and testosterone were gauged on isolated rat pituitary and Leydig cells. Tissues were incubated with D-aspartate, and then the concentration (synthesis) of LH and cGMP in the pituitary and of testosterone and cAMP in the Leydig cells was determined. In humans and rats, sodium D-aspartate induces an enhancement of LH and testosterone release. In the rat pituitary, sodium D-aspartate increases the release and synthesis of LH through the involvement of cGMP as a second messenger, whereas in rat testis Leydig cells, it increases the synthesis and release of testosterone and cAMP is implicated as second messenger. In the pituitary and in testes D-Asp is synthesized by a D-aspartate racemase which convert L-Asp into D-Asp. The pituitary and testes possesses a high capacity to trapping circulating D-Asp from hexogen or endogen sources. D-aspartic acid is a physiological amino acid occurring principally in the pituitary gland and testes and has a role in the regulation of the release and synthesis of LH and testosterone in humans and rats.

J Nutr Health Aging. 2015. Older Adults Have Delayed Amino Acid Absorption after a High Protein Mixed Breakfast Meal. To measure the postprandial plasma amino acid appearance in younger and older adults following a high protein mixed meal. DESIGN: Cross-sectional study. Healthy men and women aged 60-75 (n=15) years, and young controls aged 20-25 years (n=15) matched for body mass index and insulin sensitivity based on the homeostatic model assessment of insulin resistance. High protein mixed meal of complete food products. Circulating amino acid concentrations were determined hourly before and for 5 hours after meal ingestion. RESULTS: There was no difference between cohorts in postprandial appearance of non-essential amino acids, or area under the curve of any individual amino acid or amino acid class. However, older adults had higher baseline concentrations of aspartic acid, glutamic acid, glycine, ornithine, threonine and tyrosine and lower baseline concentrations of hydroxyproline, isoleucine, leucine, methionine and valine compared to younger adults. Younger adults showed peak essential (EAA) and branched-chain amino acid (BCAA) concentrations at 1 hour post meal while older adults' peak EAA and BCAA concentration was at 3 hours. Similarly, peak total amino acid concentrations were at 3 hours in older adults. Older adults digested and absorbed the protein within a mixed meal more slowly than younger adults. Delayed absorption of AA following a mixed meal of complete food products may suppress or delay protein synthesis in senescent muscle.