Everything You Need To Know about D-Aspartic Acid

man with elevated testosterone levels flexing

When you first start hitting the gym, the gains come easy.

Day after day, week after week, you just keep getting stronger.  After a year or two of consistent training, though, the rate at which you’re able to gain muscle starts to taper.

It gets harder and harder to progress on all your lifts.  By the time you’re a few years in, you may stop making gains altogether!

These kinds of plateaus are normal, and can be defeated by re-thinking your diet and training protocol, but sometimes you just wish there was a shortcut.

Enter: natural test-boosters.

Increasing testosterone levels is a guaranteed way to increase strength and muscle mass, so any supplement that claims to boost testosterone is going to be of interest to a lot of people.

If you’re reading this, you may have heard that D-Aspartic Acid can do just that.

  • Increase Testosterone
  • Increase Muscle Mass
  • Enhance Performance

But the research tells a much different story…

In this article, we’ll take a hard look at D-Aspartic Acid and it’s potential as testosterone booster and muscle-building supplement.

By the end, you’ll know exactly what it is, how it works (or doesn’t work), and whether or not it can benefit you.

Let’s get started…

What Is D-Aspartic Acid And What Does It Do?

D-Aspartic Acid (DAA) is the D-enantiomer of the amino acid, Aspartic Acid.

The other enantiomer of Aspartic Acid, L-Aspartic Acid, is one of the 20 proteinogenic amino acids that make up our genetic code.

D-Aspartic Acid vs L-Aspartic Acid

With the exception of Glycine, all amino acids have an L and a D enantiomer.  Much of the time, it doesn’t matter which form you use, but the in the case of D-Aspartic Acid and L-Aspartic Acid, it does.

For all intents and purposes, they’re two entirely different molecules.  They behave in different ways and play entirely different roles in the body.

For example, the D-form is not normally used to form complete proteins.  Instead, it plays a unique role in brain function and hormone production.

In the brain, DAA can function as a neurotransmitter, but it is also converted into N-Methyl-D-Aspartate (NMDA), a more common neurotransmitter.

NMDA is involved in cognitive functions, such as memory and learning, but also plays a role in Testosterone production.

This is why D-Aspartic Acid supplements are commonly marketed as Testosterone boosters.

What Are The Benefits Of D-Aspartic Acid Supplementation?

scoop of D-Aspartic Acid next to a dumbbell and shaker bottle

Some of the claims made about D-Aspartic Acid are rooted in bit of science, while others have flat out been proven wrong.

Let’s take a look at a few of the most common claims…

D-Aspartic Acid And Testosterone

D-Aspartic Acid is believed to increase Testosterone by triggering a cascade of hormonal reactions.

First, it accumulates in the Anterior Pituitary gland, which triggers the release of several hormones.

  • Gonadotropin releasing hormone (GnRH)
  • Growth Hormone Releasing Hormone (GHRH)
  • Growth Hormone
  • Luteinizing Hormone (LH)
  • Follicle-Stimulating Hormone (FSH)
  • Prolactin

In the testes, Luteinizing Hormone acts upon specialized cells, called Leydig cells, to trigger Testosterone production.

Additionally, D-Aspartic Acid appears to increase the activity of Stimulating steroidogonic Acute Regulatory protein (StAR), a transport protein that controls a rate limiting step in Testosterone production.

Now for the obvious question…

How effective is D-Aspartic Acid for boosting Testosterone in actual people?

Well, a few studies have been conducted to answer that very question.  D-Aspartic Acid has repeatedly failed to increase Testosterone levels in healthy, human subjects.

In fact, one study found that D-Aspartic Acid actually lowered Testosterone levels!

D-Aspartic Acid supplementation has been shown to restore Testosterone levels to normal in men with abnormally low Testosterone levels.

In healthy people, though, it causes only a small, short-lived increase.

So, is D-Aspartic Acid a reliable, effective test-booster?  Definitely not.

D-Aspartic Acid And Muscle Building

D-Aspartic Acid is commonly sold as a muscle-building supplement, but research indicates these claims are nonsense as well.

A few studies have measured the impact of D-Aspartic Acid on strength and/or performance and all have failed to find any kind of impact whatsoever.

The reason for this is two-fold:

First off, increasing strength and building muscle requires a much larger increase in Testosterone levels than what D-Aspartic Acid has been shown to provide.

Then there’s the issue of duration.

Due to the rapid normalization of Testosterone levels within a week or two, D-Aspartic Acid can’t elicit the sort of muscle and strength increases that generally occur when Testosterone is elevated for a prolonged period of time.

It’s possible that in men with initially low Testosterone levels, that D-Aspartic Acid could lead to an increase in muscle mass, but so far no studies have shown this to be the case.

The study I referenced above, where DAA helped restore Testosterone levels in men with Low Testosterone, didn’t measure strength or muscle mass.

So, is D-Aspartic Acid a useful muscle-builder?  No way.

D-Aspartic Acid And Sexual Health

When it comes to sexual health, D-Aspartic Acid may actually be a useful supplement.

We talked about a few of the ways that D-Aspartic Acid can potentially enhance Testosterone production, but research clearly shows it doesn’t work in healthy people with normal Testosterone levels.

It has, however, been shown to restore Testosterone levels in men with abnormally low Testosterone levels.

What does that mean?

It means men suffering from hormone-related sexual dysfunction are the most likely candidates to benefit from D-Aspartic Acid supplementation.

If you’re a healthy young man with no such issues, you’re not going to notice a difference with DAA supplementation.

D-Aspartic Acid And Cognitive Function

Since D-Aspartic Acid is easily converted into NDMA, and NDMA receptors are heavily involved in cognitive functions, such as memory and learning, D-Aspartic Acid may play a role in cognitive function.

In mice, DAA supplementation has been shown to enhance cognitive function. Specifically, it helped mice navigate a maze test faster than normal.

Unfortunately, it remains untested in humans.

While it has a legitimate mechanism of action by which it may improve cognitive function, there’s nowhere near enough evidence to draw any solid conclusions.

I’ve said it before and I’ll say it again…

Just because a supplement works in mice doesn’t mean it works in humans!

Any claim that D-Aspartic Acid “boosts cognitive ability” is pure speculation.

What Is The Clinically Effective Dosage For D-Aspartic Acid

The term clinically effective dose refers to the dosage at which a supplement has been proven effective in studies.

For D-Aspartic Acid, it’s 2 to 3 grams per day, but the question is…

Effective for what?

We know D-Aspartic Acid isn’t an effective test-booster or muscle-builder, and no human studies have investigated it’s impact on cognitive function, so we’re left with one use case.

Helping to restore Testosterone in men with abnormally low Testosterone levels.

If that’s the benefit you’re after, 2-3 grams/day will do the trick.

Due to some sort of negative feedback mechanism, whereby Testosterone is reduced after a short time, it’s not wise to take larger doses.

You may be thinking that all you need to do to boost Testosterone to a meaningful degree is just take more, but research actually indicates higher doses can lower testosterone, if anything.

Does D-Aspartic Acid Have Any Side Effects?

D-Aspartic Acid does not appear to cause side effects.  It has been shown to be perfectly safe at 2.66 grams for 90 days, with absolutely no changes in things like:

  • liver enzymes
  • red and blood cell function
  • blood glucose
  • urea
  • electrolytes

If you’ve been Googling around looking for information on D-Aspartic Acid, though, you may have read that it can cause side effects associated with higher Testosterone levels (like acne, mood swings, etc.), but that’s actually completely false.

None of the studies in which D-Aspartic Acid increased Testosterone levels noted any such side effects, probably because it doesn’t boost Test by enough to even matter and any increase is short-lived.

So, D-Aspartic Acid sucks as a test-booster and a muscle-builder, but it is safe!

How To Naturally Boost Testosterone Levels

testosterone molecule drawn in chalk

D-Aspartic Acid is a terrible test-booster, but there are some natural ways for you to boost your Testosterone levels.

Let’s talk about a few of the big ones.

Lift Weights

It’s no secret that exercise promotes healthy hormone levels, but research also shows that the type of exercises you choose to do impact hormonal response as well.

Compound exercises like:

Elicit a greater hormonal response than machine-guided exercises.

You should also dial up the intensity of your training.  Studies show that heavy lifting at decent volume is ideal for optimizing the hormonal environment.

If you’re not working out regularly, all you have to do to boost your Testosterone levels is work out!

If you do workout, but tend to use guided machines with low intensity, switch your routine up to emphasize heavy, compound exercises like the ones we mentioned above.

Eat A Balanced Diet

Eating a well-balanced diet involves two things:

  • Getting enough of each macronutrient (carbs, protein, fat)
  • Getting micronutrients and phytonutrients (from fruits and veggies)

You may have heard that high fat diets are better for optimizing Testosterone production, but studies show the difference between a high-fat diet and a moderate-fat diet is pretty negligible.

You definitely need a healthy amount of fat in your diet, but eating a high fat diet won’t boost your Testosterone by much THAT much compared to a moderate-fat diet.

Eating a low-carb diet, however, can negatively impact your Testosterone levels.

And, of course, you already know that a high protein diet is ideal for building muscle anyway.

So, the ideal diet for optimizing your Testosterone levels and building muscle is going to be one that is:

  • High Protein (around 35-40% of calories)
  • High Carb (around 40-45%  of calories)
  • Normal Fat (around 20-25% of calories)

You should try your best to consume mostly unsaturated fats.

Stick to that and you’ll feel better AND perform better.

Get Enough Sleep

Making sure you’re getting enough sleep is critical if you’re trying to naturally boost Testosterone levels.

Studies show inadequate sleep is strongly associated with decreases in Testosterone, so taking the necessary steps to achieve deeper, more restful sleep is an easy way to optimize your hormonal health.

You’ll also find that, with a goodnight’s sleep, you:

Sleeping well will literally make you an all around better, more productive person.

The Bottom Line On D-Aspartic Acid

If you’re looking for a natural test-booster that will help you build muscle, D-Aspartic Acid is going to disappoint.

It may slightly boost Testosterone in normal, healthy individuals but only for short-time.  And again, any increase is going to be minuscule.

The impact just isn’t meaningful enough to make a difference in terms of strength, performance, or muscle mass.

If you’re experiencing some kind of hormone-related sexual dysfunction, however, DAA may help by restoring hormones (namely Testosterone), but that’s about all it’s good for.

Despite the insane amount of hype, D-Aspartic Acid is pretty disappointing when you actually look at the research.

Got Anything To Add About D-Aspartic Acid?  Comment Below…

I’m Matt Theis, founder of SuppWithThat, Momentum Nutrition, and Singular Sport. I created SWT to separate the science from the hype and publish accurate, research-based information on supplements. If you like what I have to say here, feel free to check out my supplements at and

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