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D-Aspartic Acid Side Effects

Are They Real? Discover What Researchers and Reviewers Say

Low libido, erectile dysfunction, fatigue, diminished muscle growth, and fat gain are just a few side effects of low testosterone. Seeking a solution, many men turn to testosterone injections, patches, and gels.

However, these synthetic, prescription remedies are often accompanied by their own unique side effects: priapism, prostate enlargement, gynecomastia, acne, baldness, and liver damage.

Fortunately, D-aspartic acid is said to naturally increase testosterone production and release. Consequently, more and more men turn to D-aspartic acid, believing it boosts testosterone without causing side effects.

However, rumors started trickling in that D-aspartic acid actually does cause side effects. So, what is the truth?

The Alleged Side Effects of D-Aspartic Acid

Many D-aspartic acid side effect rumors originated in forums and product reviews. While many users said they didn’t have any problems while using D-aspartic acid, some users claimed the following side effects:

  • Acne
  • Headache
  • Diarrhea
  • Mood Swings
  • Depression

These side effects were generally mild and often temporary.

The problem is most users didn’t specify whether D-aspartic acid was the only ingredient or if the supplement contained others. If other ingredients were used, who can rightly say D-aspartic acid caused the side effects?

What Do Researchers Say About Side Effects?

D-Aspartic Acid Side Effects - eSupplements.com

Fortunately, researchers are more informed on D-aspartic acid side effects than athletes and bodybuilders.

For example, acne is a condition with many triggers including diet, hormone levels, and overall health. Supposing D-aspartic acid boosts testosterone, it might cause a hormonal imbalance and increase the likelihood of breakouts. But so far, there’s no proof high testosterone levels cause acne.[1]

Headaches and diarrhea are even more difficult to pin on D-aspartic acid because they have so many causes (e.g. illness, dehydration, and diet). Headache and diarrhea also may occur when a supplement user takes large dosages of any ingredient. If the body adjusts and develops tolerance, the side effects typically stop.

Similarly, mood swings are also attributed to D-aspartic acid use. D-aspartic acid converts into NMDA,[2] which may increase homocysteine levels.[3] As homocysteine levels rise, NMDA receptors become more active, which leads to mood swings and depression.[4] Luckily, these side effects can be countered by reducing homocysteine levels with folic acid or betaine.[5][6]

Side Effects in the Clinical Studies

To date, two human clinical studies have tested D-aspartic acid — one lasting 90-days and the other 12 days.

In the 90-day study, participants took 2,660 mg D-aspartic acid every day. Researchers regularly measured the participants’ electrolytes, glucose, urea, enzymes, creatinine, and blood cells and found no abnormalities. In addition, the participants didn’t experience significant side effects.[7]

Additionally, no side effects were reported during the 12-day study when participants took 3,000 mg daily.[8]

Many animal studies tested D-aspartic acid and found it causes some side effects.[9][10][11] However, the most reliable information about D-aspartic acid’s effects comes from human studies. Animal study results might apply or they might not.

Benefits of D-Aspartic Acid (DAA)

Researchers weren’t just testing D-aspartic acid’s safety when they conducted clinical studies. They wanted to know if D-aspartic acid boosts testosterone and enhances fertility.

Men taking D-aspartic acid during the 90-day study dramatically improved sperm count and motility. As a result, they became more fertile and pregnancies increased among their partners.[7]

D-Aspartic Acid Side Effects - eSupplements.com

After taking D-aspartic acid for 12 days, participants increased lutheinizing hormone and testosterone levels by 33% and 42%, respectively.[8] These are just a few benefits of high testosterone levels:

  • Greater muscle growth and strength
  • Fat loss
  • Better sleep quality
  • High libido
  • Positive mood
  • More Energy

The Bottom Line

So, does D-aspartic acid cause side effects?

According to researchers, D-aspartic acid might cause acne, headaches, diarrhea, mood swings, and depression. But there’s not enough evidence to pin D-aspartic acid as the guilty party.

Study participants didn’t experience any significant side effects or health problems. However, they did experience D-aspartic acid’s benefits: increased testosterone levels and fertility.

If you want to boost testosterone without an expensive, potentially-dangerous prescription product, D-aspartic acid is a natural, clinically proven alternative.


    Leave a Comment

    Comments (19)

    Troy R. Hansen

    June 8, 2013

    which product would you recommend?

    Mike, great article. I’ve been debating on taking d-aspartic acid as a test booster and came across this article. If you don’t mind me asking, which product would you recommend as a test booster that has a sufficient amount of d-aspartic acid to see quick results? thanks

      Mike Jackson

      Mike Jackson

      June 11, 2013

      Re: which product would you recommend?

      Troy, that’s a great question and thanks for reaching out to me. I would say the best D-Aspartic acid testosterone booster I’ve seen is Syntheroid. You get 1,560 mg of D-Aspartic in each serving, which is three times as much as you get with most testosterone boosters. And Syntheroid also has some other great ingredients that also make a difference for quick results. I hope that helps and we’d love for you to leave a review if you do give it a try.

    Nic Bernier

    November 8, 2013

    Side effects

    So there is a chance for side effects, but because the sample sizes were so small in each study we wouldn’t be able to say for sure. A small sample size can mean a larger chance for error. The effect can very from person to person, so you may get above or below average results and mild to more intense side effects, you just have to judge that for yourself. I would like to see a larger scale study conducted to support the encouraging evidence. Remember these studies support but don’t 100% percent prove anything, as any researcher would tell you.



    December 18, 2013

    Recommended product

    I used a product called Terminus which is suppose to be a testosterone booster to enhance my workouts I was blown away as I was able to workout up to 6 days a week given that recovery was enhanced along with productivity in the gym, after a few days of using it soreness was very minimal! I highly suggest this product!


    David Dressler, BA, RMT

    January 12, 2014

    Testosterone Booster

    Anything that boosts testosterone can cause acne! This is well known, the cited study aside. Anything that boosts testosterone, particularly in an older person, can produce a rise in estrogen. Estrogen is a carcinogen in men (not testosterone, as erroneously thought previously, except in men who already have cancer). Expect a rise in estrogen when taking anything designed to raise testosterone. Blood tests for testosterone, estrogen, progesterone, DHEA-S, DHT and SHBG should be taken. The 12-day experiment that found a testosterone rise and no side effects is not long enough to track hormonal changes. The 90-day experiment would have some value from that perspective. However, from what the article above said, neither experiment tested all the necessary hormone levels to establish whether or not they were balanced! How absurd. It has to be understood that raising a hormone level (testosterone) MUST cause changes in all the other steroid hormones. There is no doubt about this. This comes from one simple fact: all steroid hormones are made from cholesterol that is converted into pregnenalone and from there into the other steroid hormones including testosterone. The entire network of hormones has to be assessed as to level and relative balance one to the other. This requires a very skilled functional medical doctor, not merely an endocrinologist who merely looks at whether each hormone is within so-called “age-normal range”. And we mere mortals can’t expect to raise testosterone without upsetting the balance of the other hormones; so, we should be testing to see what introducing any testosterone source does. By the way, bioidentical testosterone is relatively safe and not to be feared in men over 40.


    Alan Schwartz

    January 14, 2014

    Aspartic acid (aspartate)is likely to be dangerous

    Dr. Russell L. Blaylock, a professor of neurosurgery at the Medical University of Mississippi, recently published a book thoroughly detailing the damage that is caused by the ingestion of excessive aspartic acid from aspartame. Blaylock makes use of almost 500 scientific references to show how excess free excitatory amino acids such as aspartic acid and glutamic acid (about 99 percent of monosodium glutamate or MSG is glutamic acid) in our food supply are causing serious chronic neurological disorders and a myriad of other acute symptoms.

    Aspartate and glutamate act as neurotransmitters in the brain by facilitating the transmission of information from neuron to neuron. Too much aspartate or glutamate in the brain kills certain neurons by allowing the influx of too much calcium into the cells. This influx triggers excessive amounts of free radicals, which kill the cells. The neural cell damage that can be caused by excessive aspartate and glutamate is why they are referred to as “excitotoxins.” They “excite” or stimulate the neural cells to death.

    Aspartic acid is an amino acid. Taken in its free form (unbound to proteins), it significantly raises the blood plasma level of aspartate and glutamate. The excess aspartate and glutamate in the blood plasma shortly after ingesting aspartame or products with free glutamic acid (glutamate precursor) leads to a high level of those neurotransmitters in certain areas of the brain.

    The blood brain barrier (BBB), which normally protects the brain from excess glutamate and aspartate as well as toxins, 1) is not fully developed during childhood, 2) does not fully protect all areas of the brain, 3) is damaged by numerous chronic and acute conditions, and 4) allows seepage of excess glutamate and aspartate into the brain even when intact.

    The excess glutamate and aspartate slowly begin to destroy neurons. The large majority (75 percent or more) of neural cells in a particular area of the brain are killed before any clinical symptoms of a chronic illness are noticed. A few of the many chronic illnesses that have been shown to be contributed to by long-term exposure to excitatory amino acid damage include:

    Multiple sclerosis (MS) Parkinson’s disease
    ALS Hypoglycemia
    Memory loss AIDS
    Hormonal problems Dementia
    Epilepsy Brain lesions
    Alzheimer’s disease Neuroendocrine disorders

    The risk to infants, children, pregnant women, the elderly and persons with certain chronic health problems from excitotoxins are great. Even the Federation of American Societies for Experimental Biology (FASEB), which usually understates problems and mimics the FDA party-line, recently stated in a review that:

    “It is prudent to avoid the use of dietary supplements of L-glutamic acid by pregnant women, infants, and children. The existence of evidence of potential endocrine responses, i.e., elevated cortisol and prolactin, and differential responses between males and females, would also suggest a neuroendocrine link and that supplemental L-glutamic acid should be avoided by women of childbearing age and individuals with affective disorders.”

    Aspartic acid from aspartame has the same deleterious effects on the body as glutamic acid.

    The exact mechanism of acute reactions to excess free glutamate and aspartate is currently being debated. As reported to the FDA, those reactions include:

    aspartame effect
    Headaches/migraines Fatigue (blocks sufficient glucose entry into brain) Anxiety attacks
    Nausea Sleep problems Depression
    Abdominal pains Vision problems Asthma/chest tightness
    One common complaint of persons suffering from the effect of aspartame is memory loss. Ironically, in 1987, G.D. Searle, the manufacturer of aspartame, undertook a search for a drug to combat memory loss caused by excitatory amino acid damage. Blaylock is one of many scientists and physicians who are concerned about excitatory amino acid damage caused by ingestion of aspartame and MSG.

    A few of the many experts who have spoken out against the damage being caused by aspartate and glutamate include Adrienne Samuels, Ph.D., an experimental psychologist specializing in research design. Another is Olney, a professor in the department of psychiatry, School of Medicine, Washington University, a neuroscientist and researcher, and one of the world’s foremost authorities on excitotoxins. (He informed Searle in 1971 that aspartic acid caused holes in the brains of mice.)



    Micheal Pattock

    February 9, 2014


    Right now my doc got me on testosterone shoots watch carefully by the doc but to get the total test up would it be ok or wise to take d-aparatic acid while on the test shoot ? Becausemy free test is 25 from 30 but my total is 131 any heads up I am really how much what about supplements but just been contemplating this.

      Mike Jackson

      Mike Jackson

      February 11, 2014


      Hi Micheal, If you are already doing prescribed testosterone treatments that your doctor is monitoring carefully, my advice would be to not put anything in your body that manipulates your hormone levels without getting your doctor’s opinion first. Your doc is going to have the most insight for your specific situation. Wish I could be more help!

    Michael M.

    March 11, 2014

    DAA Danger?

    I have to say, the talk out there that DAA can cause all kinds of serious brain/neuro problems is scary. The exitotoxin theory. Does anyone know how likely DAA is to be dangerous?


    Jack K

    April 23, 2014

    Anyone to comment on Blaylock's report?

    Can anyone (that knows), comment on Blaylock’s report. It sounds like he was motivated by a anti-aspartame feeling..but I just don’t know. Is his finding relevant to guys taking D-Aspartic Acid? After all there are two kinds of Aspartic Acid…L-Aspartic Acid and D-Aspartic acid.
    I have been taking this sup…and would like to have better (or more) information …if there is some good knowledge to be shared on this …before I might damage myself.
    This points out to one of the sad thing about spending money and taking supplements…often the consumer either wastes money…or even worse..hurts their body..



    July 2, 2014

    Russel Blaylock info

    Dr. Blaylock has retired from neurosurgery and has launched himself onto the frontlines AGAINST science. He has published opinions (read not-fact) that vaccines cause ALS, that vaccine additives cause Gulf War Syndrome (despite the fact that the additive in question was never given to service men) and that aspartame (not d-aspartic acid) cause brain damage. He also believes that the ACA was created by an extragovernmental entity that will lead to euthanasia death panels, that flouride in the water is part of a mind control plot, and that Obama is planning to use forced vaccination to bring about the New World Order.

    The guy is a tin-foil-hat wearing nutcase.
    Don’t believe me? He is a regular contributor to Alex Jones’s Infowars: http://www.infowars.com/infowars-com-saves-lives-dr-russell-blaylock-exposes-medical-genocide/

    I will pass on his “research”

    Of course, he sells his own products which are supposed to “repair” the damage caused by all of the evil conspiracy serums that big money folks done poisoned us with…derp derp derp.



    August 18, 2014

    Dietary d aspartic acid

    Can eating foods high in d aspartic acid daily at high levels substitute for supplements ? There are plenty of foods out there high in add. What do you think ?


    Mike Williams

    October 10, 2014

    Respond to the Scientism of 'craig"

    Craig..I will not waste my time trying to correct everything you wrote.
    You reference the sceptic site which is just a yes sir site for “consensus views and big pharma”.
    But if ad hominems and appeals to authority are all you have..
    In regards to Squalene..(which you mischievously didnt mention by name If it was never used..then how come some personnel can have anti bodies to it.
    Next time..just do some research …



    November 14, 2014


    At what age can you start taking DAA?



    December 27, 2014

    Is it ok

    Ran across this article after my Uncle gave me some D-aspartic acid for Christmas. I would say my test levels are pretty normal. I work out recreational about 3-5 times a week. My question is if I take this stuff and it boosts my T levels, after I am done taking it will my levels go back to normal? or will i have to keep taking some sort of supplement to get it back to normal?


    James Bryson

    January 14, 2015

    Good for this old man

    I am 61 years old and get an energy and mood boost on days I use the pure DAA, 3 grams first thing in the morning before breakfast. According to my blood work, it did cause a rise in my T from off-the-chart low to low normal. Got a similar improvement from T-shots but had to quit them due to urine hesitation. I doubt if a person with normal levels would notice any difference, but I appreciate what it does for me at my job during the day (better focus and productivity). Weight training at night: steady progress about the same as prior to supplement. Still have to be careful what I eat.



    January 19, 2015


    for me the study was simple: after a week on DAA i couldn’t open my eyes without the headache. Interesting is that i was only on DAA at the moment and the headaches stopped as soon as I stopped taking DAA. Conclusion yes it does cause a headache in some people.


    john hills

    February 5, 2015

    been on this daily for 8 weeks.

    Using this as part of my newly started weightlifting routine. 49 years old I have gained 14 pounds in 8 weeks and dropped 2 pant sizes from 38- to a tight 34.

    I noticed my testicles went from my normal (lg) to (xl) and my libido is like when I was 25 again. Might be a combo of other aminos I am taking also but I like what is happening!



    March 19, 2015

    Use caution with this stuff.

    I have been hitting the gym hard for nearly 4 months, going 5 days a week working on cardio, muscle and general strength. I’ve used numerous supplements and vitamins to aid in muscle recovery and gain.

    Not to long ago I purchased testogenx under the Ronnie Coleman series. These pills contain the D-asperic acid. After taking the correct dosage for 8 days I noticed my self having panic attacks, extreme episodes of depression and extreme anxiety. I felt as if life it self had no meaning and would nearly cry myself to sleep. Luckily when I take a new workout product I take it alone for the first few weeks to make sure it melds with my body correctly. On the back of this test booster it warns of these effects. It has been three days since I’ve had any and am feeling better and more like myself.

    I issue a warning with this type of product, be careful and stay safe. It doesn’t matter the gains if it messes with our minds.


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