Influence of a D-aspartic Acid/Sodium Nitrate/Vitamin D3 Dietary Supplement on Physiological Parameters in Middle-aged Men: A Pilot Study

Abstract

D-aspartic acid (DAA), nitrate, and vitamin D 3 have received considerable attention in recent years for their potential health-enhancing properties. Using an open-label design, we evaluated the impact of a DAA/sodium nitrate/ vitamin D 3 dietary supplement on blood testosterone and nitrate/nitrite, as well as subjective indicators of health, in middle-aged men.Methods: 10 overweight or obese men (mean age: 42 years) were assigned to ingest a DAA/sodium nitrate/ vitamin D 3 supplement (either one or two servings per day) for 28 days. Blood total and free testosterone and nitrate/nitrite was measured before and after 14 and 28 days of supplementation. Subjective assessment of to health indicators (e.g., energy level, libido) was included at each collection time.Results: Total and free testosterone increased on average 5-10%, which was not of statistical significance (p>0.05). The response was highly variable; some men failed to respond to treatment, while men with relatively low basal testosterone values experienced increases exceeding 20%. Plasma nitrate/nitrite was increased approximately 6-10 fold after treatment with the supplement, with a trend noted for a time effect (p=0.07). Men reported a significantly better feeling following supplement use, as evidenced by a time effect for both vitality (p=0.02) and libido (p=0.04), with a trend noted for increased energy level (p=0.08) and mental outlook and mood (p=0.10). Conclusion:Twenty-eight days of treatment with a DAA/sodium nitrate/ vitamin D 3 dietary supplement increased blood nitrate/nitrite and improved subjective feelings of vitality and libido in middle-aged men. In selected men with low basal testosterone values, the supplement increased circulating levels of this hormone.

The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review

“…It is similar finding by Bloomer et al and Willoughby et al and contrary to the study of Topo et al (40, 49, 50). Baseline testosterone levels of the current study were higher than values found in Topo et al and Bloomer et al experiments (6.3, 4.5 and 3 ng/mL respectively), so one can say that baseline testosterone levels may have no effect on influence of D-Asp supplementation that was previously assumed.…”

“…The authors hypothesized that 6 gr of D-Asp per day may affect negative feedback mechanisms of the HPG axis, thus reducing pituitary initiated production of luteinizing hormone and also testosterone levels. However, in the study of Bloomer et al , 6 gr daily of D-Asp had no effect on the testosterone levels (50). …”

“…Another clinical trial study, by Bloomer et al investigated the effect of DAA/sodium nitrate/ vitamin D3 supplement on bBlood total and free testosterone and nitrate/nitrite before and after 14 and 28 days in 10 overweight or obese men with the average of 42 yr (50). Although in this study basal testosterone levels of subjects were low (approximately 3 ng/mL), after 14 and 28 days of supplementation, testosterone levels were not statistically significant and that is similar to the results obtained by Topo et al and Willoughby et al (40, 49).…”

The Effects of Six-Gram D-Aspartic Acid Supplementation on the Testosterone, Cortisol, and Hematological Responses of Male Boxers Subjected to 11 Days of Nocturnal Exposure to Normobaric Hypoxia

“…However, repeating this protocol over a 12-week training period did not result in any changes in T concentration [ 21 ]. The literature also includes some studies reporting an increase in T concentration in men supplemented with DAA; however, the subjects in these groups were characterized by low baseline T concentration in the blood [ 13 , 19 , 20 ]. The average baseline T concentrations in these studies (9–16 nmol/L) were lower than those observed in our present study (13.9–25.1 nmol/L—baseline), as well as in previous studies that did not confirm the beneficial effects of DAA (18–41 nmol/L) [ 14 , 15 , 16 , 17 , 18 , 21 ].…”

“…Supplementation began four days before the first exposure to hypoxia and continued throughout the whole of the LH–TL training period. D-aspartic acid (DAA) dose and supplementation time were selected based on the methodologies of previous studies regarding the ergogenic effects of DAA [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”