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Is L-glutamine safe during pregnancy?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

The FDA label for prescription L-glutamine says there are no available data on its use in pregnant women, and that animal reproduction studies were not conducted. NIH's research summary covers adults taking up to about 45 g a day. MedlinePlus asks users to tell their doctor if pregnant. Ask your doctor before taking glutamine while pregnant.1,2,3

Key facts

  • The label says there are no available data on L-glutamine use in pregnant women to inform a risk of major birth defects or miscarriage.1
  • The label says animal reproduction studies were not conducted, and that it is not known whether L-glutamine can cause fetal harm in a pregnant woman.1
  • The main trial behind the label excluded women who were pregnant, planning pregnancy or lactating.1
  • MedlinePlus tells users of the prescription form to tell their doctor if they are pregnant, plan to become pregnant or are breastfeeding.3
  • A 2022 safety review of amino acid supplements lists pregnancy among the situations that need further research.4

What the L-glutamine label says about pregnancy

The most direct official statement about glutamine in pregnancy sits on the FDA-approved label of a prescription L-glutamine powder, which is used by people with a serious inherited blood condition. Its pregnancy section says there are no available data on use in pregnant women to inform a drug-associated risk of birth defects or miscarriage. It says animal reproduction studies were not conducted, and that it is not known whether L-glutamine can cause fetal harm or affect reproductive capacity.1

The label also lists who the trials left out. The study that led to its approval excluded patients who were pregnant, planning pregnancy or lactating, so the trial data cannot speak to those groups.1

The prescription L-glutamine label says there are no data on its use in pregnant women, and no data on glutamine in human milk or on its effect on a breastfed infant.1

What is known about glutamine amounts

Glutamine is made by the body and is the most abundant amino acid in muscle and blood. NIH says adults eat about 3 to 6 g a day from foods such as meat, poultry, fish, eggs, dairy products and legumes.2,5

Studies of glutamine supplements for exercise used amounts well above that. NIH describes a 6-week trial of almost 45 g a day in weightlifters and reports no safety concerns, and the prescription label doses its powder at 10 to 30 g a day by body weight. All of these studies were in people who were not pregnant, so none shows how those amounts behave in pregnancy.1,2

What MedlinePlus, NIH and a safety review add

MedlinePlus's page on prescription L-glutamine asks users to tell their doctor if they are pregnant, plan to become pregnant or are breastfeeding, and to call the doctor if they become pregnant while taking it. NIH's general advice is to be cautious with supplements beyond a standard prenatal supplement during pregnancy, because many have not been well tested in pregnant women.3,6

A 2022 review of side effects of amino acid supplements names pregnancy, nursing and childhood among the circumstances that need more research before amino acid supplements can be judged suitable.4

Who should ask their doctor

Ask your doctor or midwife before taking glutamine if you are pregnant or trying to become pregnant, including when it comes as a powder or inside a blend. The same goes for anyone with liver disease, a urea cycle disorder or kidney disease, because a safety review notes glutamine is broken down to ammonia and high intakes are inappropriate in liver or kidney impairment.3,4

Questions people ask

Is L-glutamine powder safe during pregnancy?

The sources checked do not report a study of glutamine powder in pregnant women. The prescription label says there are no data in pregnancy, so ask your doctor about any powder you use.1

Is L-glutamine safe when pregnant?

The label for the prescription form says no data are available and that animal reproduction studies were not conducted. That is not a finding of harm, and it is not a finding of no harm.1

Can you take glutamine while pregnant?

NIH's exercise sheet reports studies in adults up to about 45 g a day and describes none in pregnancy. MedlinePlus asks users of the prescription form to tell their doctor about a pregnancy, and your doctor can say what fits.2,3

Is glutamine from food different?

NIH says adults eat about 3 to 6 g a day in protein foods, and the body makes glutamine itself. The sources here are about supplements, which can supply many times that amount.2

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Sources

  1. L-glutamine oral powder: prescribing information (Camber Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published June 11, 2026. Opened 2026-10-07.
  2. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. Updated April 1, 2024. Opened 2026-10-07.
  3. MedlinePlus, U.S. National Library of Medicine. L-glutamine (drug information). Last revised September 15, 2017. Opened 2026-10-01.
  4. Holeček M. Side effects of amino acid supplements. Physiol Res. 2022;71(1):29-45. Opened 2026-10-01.
  5. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
  6. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements: What You Need To Know. Fact sheet for consumers. Updated January 4, 2023. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.