Can I Take Amino Acids While Pregnant?

Pregnant woman making salad.

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You walk into your first prenatal visit ready to learn everything you can about taking care of yourself and your growing baby during pregnancy. Your healthcare provider listens to your baby's heart and shows you the tiny blob on the ultrasound screen that is already growing into your child.

As your provider goes over your dietary needs, you type furiously into the notes on your phone. They tell you to eat more protein than usual because your baby needs amino acids in protein-rich foods in order to develop properly. You start to wonder whether taking amino acid supplements might be a good way to make sure that your baby gets the nutrients they need.

In fact, amino acid supplements are not recommended during pregnancy. Not enough research has been done to confirm their safety. "It is important to note that supplements are not regulated by the Food and Drug Administration (FDA), so there is a risk there could be compounds in amino acid supplements other than what's on the label," says Shena Jaramillo MS, RD, a Washington-based registered dietician nutritionist. Here is what you need to know about why you should stick to food-based sources to meet your amino acid needs.

What Are Amino Acids?

Amino acids are the building blocks of protein. Your body breaks down proteins that you eat into amino acids to be delivered to your cells. During pregnancy, the same process delivers amino acids to your growing baby, which they need to help form bones, cartilage, muscles, and skin.

"Requirements for amino acids threonine, lysine, isoleucine, and tryptophan are higher during pregnancy and continue to rise as the pregnancy progresses," notes Kim Langdon, MD, an Ohio-based OB/GYN with more than 20 years of experience.

Your body can make some of its own amino acids, but not all of them. The amino acids that you need to get from your diet are called essential amino acids. There are nine essential amino acids, and during pregnancy, there are two additional amino acids that your body cannot manufacture on its own.

If you are vegetarian or vegan, being aware of amino acids in plant-based foods and making sure you consume a full variety can help you meet your body's nutritional needs. "Those who limit meat products need to be careful about the composition of their diet," says Jaramillo. Make sure to eat a variety of plant-based protein sources, and speak with a registered dietitian who specializes in plant-based diets if you have questions or concerns.

Getting enough protein is essential while pregnant, but taking supplements is not the right way to ensure this.

Is It Safe to Take Amino Acids During Pregnancy?

It is best to refrain from taking amino acids while pregnant. Not enough research has been done to confirm whether they are safe. The limited research that has looked into their use during pregnancy reveals some concerns about how amino acids affect fetal and placental growth.

In addition, supplements deliver much more concentrated amounts of amino acids to your body than food does, and we don't know how that could affect your pregnancy.

Every pregnancy is different. Be sure to consult with a healthcare provider about your circumstances if you have any questions about taking amino acids while pregnant.

What if I Take Amino Acids Before Realizing I'm Pregnant?

If you were taking amino acids before you knew you were pregnant, try not to worry. It is unlikely that you could have done any harm to your baby. Just stop taking the amino acids and start eating more protein-rich foods with each meal and snack, such as beans, nuts, tofu, yogurt, eggs, cheese, meat, and fish.

Why You Should Not Take Amino Acids While Pregnant

Taking amino acids while pregnant is best avoided since we don't know enough about how they might affect your baby. Animal studies have shown a connection between amino acids supplements and gestational weight, but fetuses were only bigger earlier in pregnancy, and not necessarily later.

Supplements deliver nutrients to your body differently than food, as they are concentrated and may be in higher amounts. And since amino acids may not be regulated by the FDA, there's no way to guarantee the quantity that you are ingesting in each pill. Unregulated substances might also have unlisted additives that might not be safe.

Risks of Amino Acids While Pregnant

Taking amino acids while pregnant may not be safe because of the following potential risks.

Amounts and Concentrations Unclear

Amino acid supplements are not always regulated. This means that the labels may not necessarily match up to what is actually in each capsule, and you should not take a substance if you don't know how much you are taking, especially while pregnant. We also don't know what amount would be safe to take. More research might one day reveal a pregnancy-safe amount, but with no way to know whether you have crossed this potential threshold, these supplements cannot be considered safe.

May Contain Unknown Substances

Another problem with unregulated substances is the potential for unlisted additives. When you buy amino acids, they may have other ingredients in them that are not on the label. It's important to know what you are putting into your body while you are sharing your bloodstream with a developing baby. You could ingest substances that are not safe for you or your fetus when taking unregulated supplements.

Unclear Effects on Fetal Growth

Animal studies that have looked at amino acid supplements during gestation have found that taking amino acids does have an impact on fetal growth. However, that connection is unclear and did not seem to affect the birth weight of babies born on time.

These studies, done on mice, also indicated that the correlation between litter size and birth weight was negatively affected by amino acid supplements. This means that the pups continued to grow despite there possibly not being enough room. If this carries over to humans, it could have unsafe impacts on pregnancy.

When Can I Resume Taking Amino Acids?

Research on the safety of taking amino acid supplements while breastfeeding is lacking. Talk to your doctor or a registered dietitian if you think you are unable to consume enough protein- and amino-acid-rich foods during the postpartum period. They can help you create a nutrition plan to keep you and your baby strong and healthy. They can also recommend the best time, once you're finished childbirth or breastfeeding, to start or resume amino acid supplementation if you want to.

Pregnancy-Safe Alternatives

Protein helps to support your baby's growth and development and it's important to get enough during pregnancy. Instead of taking amino acids, try to get enough protein in your diet.


Eating more meat is a sure way to add protein to your diet. "Whether red meat, poultry, or fish, animal protein is going to give you the most amino acids," says Dr. Langdon. "Meat is an important part of a pregnancy diet, and fish is highly recommended."


Eggs are a good source of protein that can be enjoyed in many different recipes. If you don't eat meat, adding more eggs to your diet can help bump up your protein intake. If you don't like the taste of eggs, try cooking them into other nutritious dishes, such as a vegetable casserole or lasagna. To pack in extra benefits, choose eggs with omega 3's.

Nuts and Beans

Nuts and beans provide fiber, unsaturated fats, and protein. They are a good choice if you can digest them well and are not allergic, but especially beneficial for pregnant people who follow a plant-based diet or a mostly plant-based diet.

A Word From Verywell

Amino acids can help add protein to your diet. Although you need more protein during pregnancy, it is not recommended to take amino acid supplements. We don't know enough about how they could affect your baby. Instead, add protein-rich foods to your diet, and speak to your healthcare provider if you have any concerns about getting enough protein while pregnant or breastfeeding.

5 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Research I of M (US) C on MN, Marriott BM. Regulation of Amino Acids and Other Dietary Components Associated with Enhanced Physical Performance. National Academies Press (US); 1994.

  2. Lopez MJ, Mohiuddin SS. Biochemistry, essential amino acids. In: StatPearls. StatPearls Publishing; 2022.

  3. To CY, Freeman M, Van Winkle LJ. Consumption of a branched-chain amino acid (Bcaa) during days 2–10 of pregnancy causes abnormal fetal and placental growth: implications for bcaa supplementation in humansIJERPH. 2020;17(7):2445. doi: 10.3390/ijerph17072445.

  4. Mariotti, Gardner. Dietary protein and amino acids in vegetarian diets—a reviewNutrients. 2019;11(11):2661. doi: 10.3390/nu11112661.

  5. Mullins AP, Arjmandi BH. Health benefits of plant-based nutrition: focus on beans in cardiometabolic diseases. Nutrients. 2021;13(2):519. doi: 10.3390/nu13020519.

Additional Reading

By Elisa Cinelli
Elisa is a well-known parenting writer who is passionate about providing research-based content to help parents make the best decisions for their families. She has written for well-known sites including POPSUGAR and Scary Mommy, among others.