Quick Navigation

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.

Kamal Patel
Research analysis led by .
Reviewed by
Examine.com Team
Last Updated:

Summary of D-Aspartic Acid

Primary information, health benefits, side effects, usage, and other important details

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.

Get trusted answers to health questions that matter to you

Getting an Examine.com subscription makes it easy for you to stay informed and understand the latest nutrition research.

If you’re overwhelmed by all the possibilities of supplementation and want step-by-step instructions on what supplements to take (how much, when, and in what combinations), then the Examine.com Supplement Guides are perfect for you.

Your support keeps us 100% independent, so that we never have a conflict of interest.


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.

📝 Don't waste your time on outdated information: Get Examine Personalized for access to the latest research on 400+ supplements and their effects on 600+ health outcomes.

Already a member? Click here to log in.

Human Effect Matrix

Unlocked for Examine members

The Human Effect Matrix summarizes human studies to tell you what effects D-Aspartic Acid has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine members.
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
Testosterone

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
Estrogen
- - 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
Fat Mass
- - See study
Fat mass does not appear to be altered with D-aspartic acid supplementation alongside exercise.
grade-c
Lean Mass
- - See study
No significant influence on lean mass in otherwise healthy trained men.
grade-c
Power Output
- - 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
Weight
- - See study
No significant alterations in body weight when D-aspartic acid is taken alongside resistance training.
grade-d
Fertility
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
Luteinizing Hormone
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
Seminal Motility
Minor - See study
Seminal motility is increased 50-100% in infertile men supplementing with D-aspartic acid
grade-d
Sperm Count
Minor - See study
Improvements of sperm count in infertile men have been noted to vary between 50-100% increases over baseline.
grade-d
Sperm Quality
Minor - See study
Appears effective, needs to be compared against a comparator.
grade-d
Free Testosterone
- - See study
grade-d
Testosterone (Males)
- - See study

Become an Examine Personalized member to access the latest nutrition research on over 400 supplements across more than 600 different health goals, outcomes, conditions, and more.

Becoming an Examine subscriber unlocks the Human Effect Matrix for supplements, as well as all health topics on Examine.com. We summarize all the latest research so that you can make the best decisions for your health based on accurate and not up-to-date information.

Plus, you get a monthly summary of the latest research on the health topics you care about.

NERD Articles

Click here to subscribe to Nutrition Examination Research Digest to stay on top of the latest research.

Things to Note

Is a Form Of

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)

Get our free 5-day course on the essentials of supplementation.

At Examine.com, our incentives line up with yours — getting unbiased information. That's why we don’t sell any advertising or supplements.

Join over 250,000 people who have learned about effective versus overrated supplements, tips for buying supplements, and how to combine supplements for safety and efficacy.

Research Breakdown on D-Aspartic Acid

1Source and Structure

1.1Sources

1.2Biological Significance

1.3Structure

2Pharmacology

2.1Enzymatic Interactions

3Neurology

3.1Role an Neurotransmitter

3.2Memory

3.3Neurogenesis

4Fat Mass and Obesity

4.1Fat Mass

5Skeletal Muscle and Physical Performance

5.1Hypertrophy

5.2Power Ouput

6Interactions with Organ Systems

6.1Male Sex Organs

6.2Female Sex Organs

6.3Hypothalamus

6.4Pituitary

7Interactions with Hormones

7.1Pituitary Hormones

7.2Pineal Hormones

7.3Testosterone

7.4Estrogen

8Safety and Toxicology

8.1General
Click here to see all 54 references.

  • Examine.com is
    100% reader-supported

    We don't accept ads or corporate funding, or sell supplements.

    Becoming a member gives you access to monthly updates on studies and access to our database of 10,000+ study details.

    Try free for 7 days

This page is regularly updated, to include the most recently available clinical trial evidence.

Each member of our research team is required to have no conflicts of interest, including with supplement manufacturers, food companies, and industry funders. The team includes nutrition researchers, registered dietitians, physicians, and pharmacists. We have a strict editorial process.

This page features 54 references. All factual claims are followed by specifically-applicable references. Click here to see the full set of research information and references for D-Aspartic Acid.

Examine.com is intended to be used for educational and information purposes only. Examine.com and its Editors do not advocate nutritional supplementation over proper medical advice or treatment and this sentiment will never be expressed through pages hosted under Examine.com. If using any pharmaceuticals or drugs given to you by a doctor or received with a prescription, you must consult with the doctor in question or an equally qualified Health Care Professional prior to using any nutritional supplementation. If undergoing medical therapies, then consult with your respective Therapist or Health Care Professional about possible interactions between your Treatment, any Pharmaceuticals or Drugs being given, and possible nutritional supplements or practices hosted on Examine.com.

Examine.com does not assume liability for any actions undertaken after visiting these pages, and does not assume liability if one misuses supplements. Examine.com and its Editors do not ensure that unforeseen side effects will not occur even at the proper dosages, and thereby does not assume liability for any side effects from supplements or practices hosted under the domain of Examine.com.

Supplements

Articles

Health Topics

NERD

Personalized

Protein Intake Guide

About

Never miss an update!

Your e-mail is safe with us. We don’t share personal data.

This website is certified by Health On the Net Foundation. Click to verify.