The Claim

In late-pregnant Yili mares, daily supplementation with 30 grams of L-citrulline increases plasma estradiol concentration by 14.81% and elevates urinary conjugated estrogens (ESS, 17α-DHEQS, E2), indicating enhanced estrogen synthesis and metabolic flux during late gestation.

Source: The Effects of L-Citrulline on the Apparent Digestion and Metabolism of Nutrients, Blood Hormone Levels, Amino Acid Metabolism and the Diversity of Faecal Microbiota in Mares in the Later Stage of Pregnancy

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
19score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

In late-pregnant Yili mares, daily intake of 30 grams of L-citrulline raises plasma estradiol levels by 14.81% and increases urinary conjugated estrogens, reflecting higher estrogen production and metabolic activity during late pregnancy.

See the scientific wording

In late-pregnant Yili mares, daily supplementation with 30 grams of L-citrulline increases plasma estradiol concentration by 14.81% and elevates urinary conjugated estrogens (ESS, 17α-DHEQS, E2), suggesting enhanced estrogen synthesis and metabolic flux during late gestation.

Why this might work

L-citrulline is absorbed and turned into arginine, which makes nitric oxide that opens blood vessels in the placenta. This brings more blood and nutrients to the placenta while reducing harmful oxidative stress. The placenta then produces more estrogen and processes it into forms that show up in urine.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: The Effects of L-Citrulline on the Apparent Digestion and Metabolism of Nutrients, Blood Hormone Levels, Amino Acid Metabolism and the Diversity of Faecal Microbiota in Mares in the Later Stage of Pregnancy

    Giving pregnant horses 30 grams of L-citrulline every day made their bodies produce more of a pregnancy hormone called estrogen, and their urine showed more signs of this hormone being processed—just like the claim said.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.