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D-Aspartic Acid

D-aspartic acid (D-AA) is an amino acid regulator of testosterone synthesis and may act on a stimulatory receptor (NMDA). D-AA shows promise in aiding male fertility. Healthy men supplementing D-AA experience only temporary increases in testosterone, which limits its use.

Our evidence-based analysis on d-aspartic acid features 54 unique references to scientific papers.

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Summary of D-Aspartic Acid

Primary Information, Benefits, Effects, and Important Facts

D-aspartic acid is one of two forms of the amino acid aspartic acid. The other form is L-aspartate.

The benefits of D-AA are specific to it, and do not extend to aspartic acid or L-aspartate.

D-AA can be used as a testosterone booster for infertile men, and by athletes as a temporary booster. Elevated testosterone levels only last a week to a week and a half in healthy men, with testosterone returning to normal afterward.

D-AA works in the central brain region to cause a release of hormones, such as luteinizing hormone, follicle-stimulating hormone, and growth hormone. It may also build up in the testicles, where it alleviates a rate-limiting step of testosterone synthesis, which leads to a minor testosterone increase.

Further research is needed on D-AA, as most studies attempt to assess D-AA’s role in the body under normal conditions, and not in the frame of supplementation.

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How to Take

Medical Disclaimer

Recommended dosage, active amounts, other details

The standard dose for D-aspartic acid is between 2,000 – 3,000mg.

D-AA is taken daily.

Different studies have used different supplementation protocols. One study used 3,000mg for 12 days, taken daily, followed by a week with no supplementation. A different study did not cycle D-AA, and used 2,000mg of continual daily supplementation with no harm. Further study is needed to determine whether D-AA should be cycled.

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Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects d-aspartic acid has on your body, and how strong these effects are.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-c
Minor
- See all 3 studies
There appears to be an increase in testosterone in most subjects acutely (6-12 days), and while this may persist to the tune of 30-60% in infertile men it is reduced to baseline within a month in otherwise healthy men with normal testosterone at baseline. However, high doses also seem to decrease free testosterone and total testosterone in resistance trained men.
grade-c - - See study
Despite a possible induction of aromatase seen in some species, D-aspartic acid supplementation does not appear to increase serum estrogen.
grade-c - - See study
Fat mass does not appear to be altered with D-aspartic acid supplementation alongside exercise.
grade-c - - See study
No significant influence on lean mass in otherwise healthy trained men.
grade-c - - See study
Otherwise healthy trained men do not experience a further increase in power output relative to placebo when D-aspartic acid is taken alongside resistance training.
grade-c - - See study
No significant alterations in body weight when D-aspartic acid is taken alongside resistance training.
grade-d Notable Very High See 2 studies
Limited evidence for D-aspartic acid suggest an increase in fertility of men, with one study noting that a group went from no conceptions to 26.6% of subjects reporting conception over 90 days.
grade-d Minor - See study
An increase in LH concentrations has been noted to 30-60% in infertile men, correlating well with the testosterone increases seen in this study.
grade-d Minor - See study
Seminal motility is increased 50-100% in infertile men supplementing with D-aspartic acid
grade-d Minor - See study
Improvements of sperm count in infertile men have been noted to vary between 50-100% increases over baseline.
grade-d Minor - See study
Appears effective, needs to be compared against a comparator.
grade-d - - See study
grade-d - - See study

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Things to Note

Other Functions:

Primary Function:

Also Known As

D-AA, D-Aspartate, DAA

Do Not Confuse With

DL-Aspartate, Aspartate

  • D-Aspartic Acid may be slightly stimulatory (NMDA receptor)

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Click here to see all 54 references.