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L-ornithine explained: what it is and what it does

EFSA (the European Food Safety Authority) says it is an amino acid that is not used to build proteins, the human body makes it, and it plays a role in the body's urea cycle. EFSA names proposed daily amounts of 450 to 900 mg. Three products we reviewed list L-ornithine, but none prints its individual amount.

By HowNook's Health desk · Updated

OHONH₂NH₂OHONH₂NH₂
What it is
Amino acid
Amounts EFSA names
Proposed daily amounts are 450 to 900 mg.
In the products we reviewed
3, none prints the amount

What L-ornithine is

  • L-ornithine is an amino acid that is not used to build proteins.1
  • Another name for L-ornithine is (+)-(S)-2,5-diaminovaleric acid.1
  • L-ornithine plays a role in the body's urea cycle.1
  • The human body makes L-ornithine.1

How much L-ornithine each product gives

Per serving, as each label prints it, against the amounts EFSA names

EFSA: 450 mg to 900 mg per dose

Amount not printed: the dashed line shows the most it can be, the whole blend

GlucoTonicNot printed · at most 200 mg
Sugar DefenderNot printed · at most 200 mg
Glyco HarmonyNot printed · at most 200 mg

The 3 products we reviewed that list L-ornithine

ProductForm and servingL-ornithine per servingOur scorePrice a bottleBuy
GlucoTonic#1 in blood sugar supportLiquid drops1 mlNot printedIn a 200 mg proprietary blend9.9$49Check price
Sugar Defender#3 in blood sugar supportLiquid drops1 mlNot printedIn a 200 mg proprietary blend9.5$49Check price
Glyco Harmony#5 in blood sugar supportLiquid drops1 mlNot printedIn a 200 mg proprietary blend9.3$49Check price
Prices checked Oct 5, 2026

Questions people ask

What is L-ornithine?

L-ornithine is an amino acid that is not used to build proteins, according to EFSA (the European Food Safety Authority). EFSA also says the human body makes it.

What does L-ornithine do in the body?

L-ornithine plays a role in the body's urea cycle, according to EFSA (the European Food Safety Authority).

What daily dose of L-ornithine does EFSA name?

EFSA (the European Food Safety Authority) names proposed daily amounts of 450 to 900 mg for L-ornithine.

Which supplements we reviewed contain L-ornithine, and how much?

GlucoTonic, Sugar Defender and Glyco Harmony all list L-ornithine. Each places it inside a 200 mg proprietary blend per 1 ml serving, without printing its individual amount. The 200 mg figure is for the blend, not L-ornithine alone.

Also in these products

All ingredients

Sources

The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.

  1. 1EFSA Journal (2011), scientific opinion 2251efsa.onlinelibrary.wiley.com/doichecked