Quick answer

Nothing in the research shows an effect of L-glutamine that is specific to women. Two exercise trials reported results for women: one included 8 women and 8 men, the other 44 women aged 60 to 80 taking 10 g a day. Most glutamine trials enrolled men.^1,2,3

Key facts

Most human trials of glutamine and exercise enrolled men, which a 2026 review says may hide differences between the sexes.³
In the soreness trial of 8 women and 8 men, the faster return of leg force may have been greater in men than in women.¹
A 30-day trial in 44 women aged 60 to 80 gave 10 g a day, and its groups held 10 to 12 women each.²
The prescription L-glutamine label says there are no data on its use in pregnancy or on glutamine in human milk.⁴
Adults take in about 3 to 6 g of glutamine a day from protein foods, and US women eat about 69 g of protein a day on average.⁵

The trials that included women

We found two exercise trials of glutamine that report results for women, and no trial of glutamine in women for any other purpose. That is a thin base, and it is worth knowing exactly what each one did.^1,2

In the soreness trial, 8 women and 8 men took glutamine or placebo. Soreness ratings were lower in the group as a whole, but the faster return of leg force may be greater in men than in women.^1,5

In that crossover trial, young adults took 0.3 g of glutamine per kg of body weight a day for the 72 hours around a hard session of knee extensions, and repeated the session on placebo. Soreness ratings were lower with glutamine in the group as a whole. Men reached higher leg force at one test speed, and the authors suggest the effect on force recovery may be greater in men.¹

In a 30-day trial of 44 women aged 60 to 80, each woman took 10 g of glutamine mixed with 10 g of maltodextrin a day, or maltodextrin alone. Peak knee muscle torque was higher at the end than at the start in the groups taking glutamine. The paper reports these changes within each group of 10 to 12 women, not as a contrast with the placebo groups.²

Its 44 women were split into four groups, by whether they exercised regularly and whether they took glutamine or placebo, and the glutamine was mixed with maltodextrin. With groups that small, and no reported contrast against the placebo groups for torque, the trial cannot show that glutamine added the strength.²

Most human trials of glutamine and exercise enrolled men. The authors of a 2026 review say this may hide differences between men and women.³

Both of the gut trials that tested single doses of glutamine before running in the heat enrolled 10 men and no women, so the gut findings below come from men.^6,7

Supplies glutamine, a fuel for cells of the gut lining; a benefit from 3 g a day is unproven*^6,7,8,9

Early evidence

The fuel role is established physiology. But a 2024 meta-analysis of 10 trials (352 adults, mostly people under medical care) found no overall effect on gut permeability, with an effect only at more than 30 g a day. In 10 men running in the heat, single doses of about 15 to 54 g lowered a marker of gut permeability, while about 20 g did not help in another trial of 10 men. None of these tested a dose near 3 g.

Amount studied: Single doses of about 15 to 54 g before exercise, and more than 30 g a day in trials of people under medical care

Adds to the body's own glutamine during very heavy training, when blood levels can dip; a benefit is unproven*^5,10,11

Early evidence

Prolonged, exhausting exercise is linked to a fall in blood glutamine. But a meta-analysis of 25 trials in athletes concluded that glutamine generally has no effect on immune measures, aerobic performance or body composition, and the NIH says research does not support taking glutamine alone to improve performance. One trial in 16 adults found less soreness and faster strength recovery at about 0.3 g per kg of body weight a day, roughly 21 g for a 70 kg person.

Amount studied: About 0.3 g per kg of body weight a day in the soreness trial, roughly 21 g for a 70 kg adult; up to about 45 g a day in others

Does the amount change for women?

No trial we found set a different glutamine amount for women. The soreness trial scaled the amount to body weight, at 0.3 g per kg a day, which comes to about 18 g for a 60 kg woman. The trial in women aged 60 to 80 used a flat 10 g a day.^1,2

Adults take in about 3 to 6 g of glutamine a day from protein foods, and the body makes more.^5,12

Glutamine comes with protein, and NIH lists meat, poultry, fish, eggs, dairy products and legumes as the foods that supply it. NIH also reports that average protein intake in the US is about 69 g a day for women and 100 g a day for men, so what food supplies depends on how much protein you eat.^5,12

Skin, hair and other questions

People often search for glutamine and skin or hair. We searched the medical literature for trials of glutamine supplements for either in healthy adults and found none, so we make no claim about them.

What's in ours

What’s in ours

BCAA 2:1:1: L-Glutamine, 1,000 mg per serving, from the label

Pregnancy, breastfeeding and other cautions

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.⁴

Ask your doctor before taking glutamine if you are pregnant, trying to become pregnant or breastfeeding. A missing study is not a finding of safety, and the label gives no way to judge the risk.⁴

The other usual cautions apply to women as to men. Ask first if you have liver disease, kidney disease or a urea cycle disorder, are in cancer treatment, are under 18, or take prescription L-glutamine, which is a medicine for sickle cell disease.^4,8,13

Glutamine is broken down to ammonia, and a safety review says high intakes are inappropriate for people with liver or kidney impairment.⁸

Questions people ask

Does L-glutamine work differently in women?

That has not been shown either way. Most trials enrolled men, and the two that reported women were small. In one soreness trial, the faster return of leg force may have been greater in men than in women.^1,3

How much L-glutamine should a woman take?

There is no recommended amount, and no trial set a different amount for women. Studies dosed by body weight, such as 0.3 g per kg a day, or a flat 10 g a day in women aged 60 to 80.^1,2,5

What do trials in women over 60 show?

One 30-day trial of 44 women aged 60 to 80 reported higher knee muscle torque in the glutamine groups than at their own starting point. The groups held 10 to 12 women and no contrast with placebo was reported for torque, so it does not show that glutamine caused the change.²

Is L-glutamine safe while pregnant or breastfeeding?

That is not known. The prescription L-glutamine label says there are no data in pregnant women and no data on glutamine in human milk. Ask your doctor before taking it.⁴

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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