D-Aspartic Acid's Uses and Safety

Popular for exercise performance, it may also affect cognitive function.

Medically reviewed by Melissa Nieves, LND

D-aspartic acid (D-asp) is an amino acid that is important for both the endocrine system and the central nervous system (the brain and spinal cord). It may function as a neurotransmitter, a chemical messenger that transmits signals between nerves and other cells, though scientists debate this role.

This article discusses the potential benefits and risks of D-aspartic acid supplementation.

What Is D-Aspartic Acid?

D-aspartic acid binds to N-methyl-D-aspartate receptors (NMDARs) in the brain and helps control neuroplasticity and brain activity. It also helps regulate hormones like:

D-asp is made in the body. Levels in the brain are highest before birth, while levels in the endocrine glands increase after birth. It's also found in the following foods:

D-aspartic acid is also available as a dietary supplement in capsule and powder form.

It has been studied for conditions like schizophrenia, Alzheimer's disease, autism, and hormone-related issues like fertility.

D-Aspartic Acid Supplement Facts

  • Active ingredients: Aspartic acid

  • Alternate names: D-aspartate, aminosuccinic acid

  • Legal status: Over-the-counter (OTC) supplement in the U.S.

  • Suggested dose: 3–6 grams a day for up to three months has been studied in clinical trials

  • Safety concerns: hasn't been studied in pregnancy, lactation, children, older adults, or those with chronic conditions



Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Although D-aspartic acid is commonly promoted as an ergogenic aid to increase exercise performance, it has not been studied much in humans for this or any other condition.

Here's what the latest research suggests about the potential benefits of D-asp.

Boosting Testosterone Levels

D-asp has been shown to increase testosterone levels in some populations, though the evidence is inconsistent.

For males without athletic training, supplementing with 3 grams a day of D-asp can increase testosterone levels by 42%. However, taking up to 6 grams daily has not shown benefit for males trained in weight lifting, either in testosterone concentrations or athletic performance.

A systematic review concluded that D-aspartic acid supplements may only increase testosterone in males with low baseline levels.

Discuss testosterone replacement therapy or other supplements that may increase your testosterone levels with your healthcare provider if you have low levels and problematic symptoms.

<p>Luza Studios / Getty Images</p> Taking a break from exercise with a protein shake

Luza Studios / Getty Images

Taking a break from exercise with a protein shake


D-asp may improve fertility, but more data is necessary.

A product containing D-asp plus folic acid and vitamins B6 and B12 nearly doubled sperm concentration and mobility in a small study of 60 males. This resulted in a higher pregnancy rate for the partners of those who used the combination product.

Although D-asp hasn't been well studied for female fertility, higher levels in the ovaries were associated with younger age and high egg quality.

More robust clinical trials are necessary before D-aspartic acid can be routinely recommended for fertility. Discuss treatment options with your healthcare provider if this concerns you.


Early research suggests that D-aspartic acid helped reduce symptoms in people with treatment-resistant schizophrenia.

It's been studied in mice models, which showed that those with high levels of D-asp had increased brain connectivity and spatial memory. Very small studies—up to 20 people—showed that D-asp levels were 30% lower in the brains of people with schizophrenia than those without.

Clinical trials in humans are necessary to confirm these effects.

Keep in mind that mental health conditions like schizophrenia should not be self-treated. If not appropriately managed, quality of life and functioning could decline.


D-aspartic acid has been studied in clinical trials at doses of 3–6 grams per day for fertility and testosterone enhancement.


Avoid D-aspartic acid if you're allergic to it or its components (parts).

Seek immediate medical attention if you have a severe allergic reaction (itching, hives, shortness of breath, etc.).

Side Effects

In general, very little safety data is available for amino acid supplements like D-aspartic acid. This means not enough is known about these supplements' safety, particularly at high doses or with long-term use.

Increased amounts of any amino acid can cause an imbalance in other amino acid concentrations in the body, including lower levels of these other amino acids.

D-aspartic acid may cause the following side effects, according to a clinical trial:


Because D-aspartic acid may alter levels of testosterone and estrogen, it can interact with other medications that affect these hormones. A few common examples of medicines that affect hormone levels include:


D-aspartic acid supplements may be riskier for some than others. Keep the following precautions in mind when deciding if D-aspartic acid is suitable for you.

There's not enough safety data to recommend D-asp for people with chronic conditions or those who are:

  • Pregnant

  • Lactating

  • Over age 65

  • Children

To optimize safety, consult your healthcare provider, pharmacist, or registered dietitian before taking dietary supplements.

Similar Supplements

Many dietary supplements are marketed as testosterone boosters, though for some, there is very little evidence to support these claims. Some supplements people take to increase testosterone levels include the following:

Before taking supplements to boost testosterone, discuss your goals with your healthcare provider so they can tailor your treatment plan to you.

Some supplements that may help symptoms of schizophrenia include the following:

Note that these supplements do not replace first-line therapy with antipsychotics. There's not enough evidence to recommend them unless a healthcare provider who can monitor your condition is following you closely.


Dietary supplements are not regulated like pharmaceutical drugs in the United States. They can cause interactions with medications or have other safety concerns. Further information about choosing supplements wisely may be found here.


D-aspartic acid is an amino acid that is made in the body and obtained through the diet. It's important for brain function and the endocrine system.

It's often marketed as a testosterone booster or performance enhancer in supplement form.

Though D-aspartic acid may benefit fertility or schizophrenia, it's too soon to know. There's little evidence that this supplement increases testosterone, strength, fertility, or mental health for now.

Frequently Asked Questions

What is D-aspartic acid?

D-aspartic acid is an amino acid that is involved in brain development and hormone regulation.

What does D-aspartic acid do?

D-aspartic acid is important for nerve signaling and the release of hormones like testosterone, prolactin, and oxytocin. It's a crucial part of the reproductive process of mammals, though its effects in humans are less studied.

D-aspartic acid supplements may improve fertility or decrease symptoms of schizophrenia, but more clinical trials in humans are necessary to know for sure.

Is D-aspartic acid safe?

We don't know for sure because there are very limited clinical trials, and most don't report side effects. More research is necessary to understand the safety of D-aspartic acid.

Read the original article on Verywell Health.