Are Amino Acids Safe During Pregnancy?

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You may be taking or considering taking amino acid supplements but wonder if you should continue if you become pregnant. Amino acid supplements, single or in various combinations, are marketed to people interested in their purported effects on athletic performance, mood, depression, and a variety of health conditions.

Unfortunately, there is little information about the safety of amino acid supplements (such as tyrosine, phenylalanine, tryptophan, and 5-HTP) during pregnancy, or there are specific warnings about using these supplements while pregnant or breastfeeding. They are best avoided during pregnancy.

Safety Concerns

Amino acids are the building blocks of protein and your body breaks down the protein from animal and plant sources in your diet to provide the amino acids required for your cells and your growing baby.

Your need for protein rises through pregnancy, but the typical American diet provides more than enough protein. Getting a variety of protein from different sources can help ensure you get a full range of amino acids.

Although amino acids are in foods containing protein, the amount found in amino acid supplements is much greater than that found in a normal diet. Consuming an abnormal amount of any one substance has a chance of effects on your body, both intended and unintended.

The safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established.

Keep in mind that supplements haven't been tested for safety and dietary supplements are largely unregulated. In some cases, the product may deliver doses that differ from the specified amount for each herb. In other cases, the product may be contaminated with other substances such as metals.

Specific Warnings

While you may be led to believe a certain manufacturer uses "natural" or "pure" ingredients, most of the ingredients come from the same handful of manufacturers. You are often not getting what you thought you were paying for. Here are some specific warnings you need to be aware of.

  • L-tryptophan: This amino acid is listed as likely unsafe during pregnancy and not enough is known about its safety during breastfeeding. It can cause a white blood cell disorder called eosinophilia and it can make liver or kidney disease worse. It can cause side effects such as nausea and vomiting.
  • 5-HTP and L-arginine: There is not enough reliable information about the safety of these supplements while pregnant or breastfeeding. It's best to be safe and not take them as supplements.

A Word From Verywell

If you're pregnant and considering using amino acid supplements (or any other form of alternative medicine), it is crucial that you consult your obstetrician first. Self-treating may have serious consequences. If you have depression, it is much safer for you and your baby to get medical help and use only medications that are appropriate for pregnant or nursing women.

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3 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. Elango R, Ball RO. Protein and amino acid requirements during pregnancy. Adv Nutr. 2016;7(4):839S-44S. doi:10.3945/an.115.011817

  2. MedlinePlus. L-tryptophan. Updated June 21, 2019

  3. MedlinePlus. 5-HTP. Updated February 12, 2019

Additional Reading
  • MedlinePlus. L-arginine. Updated October 25, 2019