Aspartic Acid
OTHER NAME(S): aspartic acid, D-AA, D-Asp, D-aspartic acid, L-AA, L-Asp, L-aspartic acid
Overview
Aspartic acid is a nonessential amino acid that your body uses for many important functions within the nervous and reproductive systems. It is sometimes taken as a supplement to increase testosterone levels, athletic performance, and muscle strength. However, since your body makes aspartic acid on its own, it is not clear if aspartic acid supplements offer any benefits. Before taking aspartic acid, tell your health care provider about all of your health conditions and any medicines or supplements you may be using.
Uses
What is aspartic acid used for?
Aspartic acid is a nonessential amino acid (meaning your body can make it). It is commonly used for a variety of reasons, but its benefits are not well defined. Some common reasons for taking aspartic acid include the following.
- To increase testosterone levels
- For better athletic performance
- To improve muscle strength
Note: The FDA has not reviewed aspartic acid for safety and effectiveness. Learn more about dietary supplements here.
How does aspartic acid work (mechanism of action)?
There are two forms of aspartate, L-aspartic acid and D-aspartic acid. Both of these are amino acids, which are the building blocks of protein. L-aspartic acid is a nonessential amino acid, which means that it is made naturally by the body. L-aspartic acid and D-aspartic acid are the building blocks for substances that help with normal nervous system function. D-aspartic acid is used to make proteins and other substances that are used by the nervous system or reproductive system.
Data are conflicting about whether taking an aspartic acid supplement increases testosterone levels, affects athletic performance, or improves muscle strength. In theory, it makes sense that taking an aspartic acid supplement could affect testosterone levels based on it telling your brain to release other hormones that lead to testosterone production. However, studies have not consistently shown that it actually does increase testosterone levels.
Aspartate plays a role in the “urea cycle” and the Krebs cycle, which are processes your cells use to make energy. In theory, having more aspartic acid available might help muscles use energy more efficiently during exercise. Hard exercise can cause ammonia or lactate to build up in your muscles, which leads to fatigue or tiredness. Aspartic acid helps the body convert and clear ammonia from your body. So, the idea is that supplementing with aspartic acid might help you feel less tired and be able to exercise longer before feeling worn out. However, studies have not consistently shown this to be true.
How should I store aspartic acid?
You should store aspartic acid according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.
Side Effects
What are the most common side effects of aspartic acid?
Aspartic acid seems to be well tolerated. But there is not enough research to know what the common side effects may be. Tell your health care provider if you have any side effects that bother you.
There may be side effects of aspartic acid that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of aspartic acid?
While less common, the most serious side effects of aspartic acid are described below, along with what to do if they happen.
Severe Allergic Reactions. Aspartic acid may cause allergic reactions, which can be serious. Stop taking aspartic acid and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Precautions
Who should not use aspartic acid?
Allergies to Ingredients. People who are allergic to any of the following should not take aspartic acid.
- Aspartate
- Aspartic acid
- D-AA
- D-Asp
- D-aspartic acid
- L-AA
- L-Asp
- L-aspartic acid
- Any of the ingredients in the specific product
Your pharmacist can tell you all of the ingredients in the specific aspartic acid products they stock.
What should I know about aspartic acid before using it?
Aspartic acid is a dietary supplement. It cannot be marketed to treat or cure a disease.
Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.
Keep aspartic acid out of the reach of children.
The FDA has not tested aspartic acid products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.
What should I tell my health care provider before using aspartic acid?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if aspartic acid is right for you.
In particular, make sure that you discuss any of the following.
Current and Past Health Conditions. Tell your health care provider if you have any of the following.
- Kidney problems
- Liver problems
- Low testosterone levels
Pregnancy. It is not known how aspartic acid could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.
Breastfeeding. It is not known if aspartic acid passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Does aspartic acid interact with foods or drinks?
There are no known interactions between aspartic acid and foods or drinks.
It is unknown if drinking alcohol will affect aspartic acid.
Does aspartic acid interact with medicines (drug interactions)?
Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
The interactions between aspartic acid and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with aspartic acid is incomplete. Always check with your health care provider before taking aspartic acid with any medicines.
Dosing
What should I do if I accidentally use too much aspartic acid?
If you or someone else has used too much aspartic acid, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
Aspartic acid is available as a dietary supplement that is taken by mouth. Speak with a health care provider about how to use aspartic acid safely. Do not take double or extra doses, even if you miss a dose.
References
- Andrology: “The chronic alcohol consumption influences the gonadal axis in men: Results from a meta-analysis.”
- Archives Internationales de Physiologie, de Biochimie et de Biophysique: “Effect of arginine aspartate on the exercise-induced hyperammoniemia in humans: a two periods cross-over trial.”
- International Journal of Reproductive BioMedicine: “The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review.”
- Nutrients: “Aspartic acid in health and disease,” “Sodium L-Aspartate supplementation improves repeated-sprint performance.”
- PLoS One: “The effects of d-aspartic acid supplementation in resistance-trained men over a three month training period: A randomised controlled trial.”
- Reproductive Biology and Endocrinology: “The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats.”