Arginine
Arginine is the amino acid the body turns into nitric oxide, the signal that widens blood vessels. It also clears ammonia and helps build creatine, and healthy adults make enough of it themselves.
4 nitrogen atomsin each molecule, the most of any amino acid
Conditionally essential the body usually makes enough
Daily requirement · none set, because healthy adults make it
- Main sources Meat, fish and dairy then nuts, seeds and soy
- Made from Citrulline mostly in the kidneys
- Becomes Nitric oxide plus urea and creatine
- In Caltide Not totaled yet no food data for it
No official daily amount or upper limit exists for arginine. Sources are listed at the end of this page.
Foods High in Arginine
Every food with protein has some arginine. The foods below supply the most.
- Meat, poultry and fishrich sources, as they are for most amino acids
- Nuts and seedspeanuts, pumpkin seeds, almonds and walnuts are among the richest plant sources
- Soy and other legumestofu, soybeans, lentils and chickpeas
- Dairy and eggsalso supply it, as part of their protein
- SupplementsL-arginine and its salts, and citrulline, which the body turns into arginine
Caltide's food data does not list arginine yet, so foods are named without figures.
What Is Arginine?
Arginine is one of the 20 amino acids that build protein, and the richest in nitrogen: of the atoms in it other than carbon and hydrogen, four are nitrogen and two are oxygen. That nitrogen is what the body uses it for, in three very different jobs.
Arginine and Nitric Oxide
The cells lining blood vessels use an enzyme, nitric oxide synthase, to split nitric oxide off arginine. Nitric oxide is a gas that tells the muscle in the vessel wall to relax, so the vessel widens and blood flows more easily. The leftover piece of arginine is citrulline, which the body can recycle back into arginine.
Arginine and the Urea Cycle
Breaking down protein releases ammonia, which is toxic to the brain. The liver locks it into urea through a loop of reactions called the urea cycle, and arginine is the last step: an enzyme cuts urea off arginine, and the urea leaves in urine.
Arginine and Creatine
The kidneys join part of arginine to glycine, and the liver finishes the job, to make creatine, the energy buffer in muscle.
How Much Swallowed Arginine Reaches the Blood
The gut wall and liver break down a large share of oral arginine before it reaches the rest of the body. Citrulline takes a detour: it passes the gut and liver largely untouched, and the kidneys turn it into arginine. In studies that compared the two, oral citrulline raised blood arginine more effectively than oral arginine.
When Arginine Becomes Essential
Healthy adults make enough arginine, so no daily requirement is set. Babies, especially preterm ones, and people recovering from severe burns, major surgery or serious infection can need more than they make, which is why it is called conditionally essential.
Every food in the food library shows its protein; arginine figures are not in it yet.
Arginine Supplements
Food is the main source, but supplements are a source too, alone or in pre-workout blends.
Arginine Supplement Forms
L-arginine is the plain amino acid. Arginine hydrochloride (HCl) and arginine alpha-ketoglutarate (AAKG) bind it to another compound, so a gram of either holds less than a gram of arginine. Check whether the label gives the arginine or the whole compound.
What Studies Show About Arginine Supplements
Trials for blood pressure, erectile dysfunction and exercise performance are mostly small and short, with mixed results. In a 2006 trial in people who had just had a heart attack, arginine did not help, and the trial was stopped early after more deaths in the arginine group.
Medicines That Interact With Arginine
- Blood pressure medicines and nitratestogether they may lower blood pressure too far
- Erectile dysfunction drugssuch as sildenafil, which also act through nitric oxide
Stomach upset and diarrhea are the common side effects. Ask a doctor or pharmacist before combining a supplement with a medicine. Not medical advice.
Tracking Arginine in Caltide
- Not totaled yetCaltide's food data does not include arginine, so Caltide does not add it up in the Nutrition tab yet. You can still list L-arginine as an ingredient when you add a supplement.
Related Nutrients
Arginine Sources and References
The figures and claims on this page are checked against these sources.
Questions About Arginine
It is conditionally essential. Healthy adults make arginine from citrulline in the kidneys, but during fast growth, severe burns, injury or serious illness the body may need more than it can make.
It is the raw material for nitric oxide, which relaxes blood vessel walls. It also carries nitrogen into the urea cycle, which turns toxic ammonia into urea, and gives part of its structure to creatine.
Protein foods: meat, poultry, fish, eggs and dairy, plus nuts and seeds such as peanuts and pumpkin seeds, soy and other legumes.
Because the gut and liver break down much of the arginine you swallow before it reaches the blood. Citrulline passes them largely intact and the kidneys turn it into arginine, so in studies oral citrulline raised blood arginine more effectively than oral arginine.
Some trials found a small drop, but they were small and short, and results differ. It is not a substitute for blood pressure treatment, and combined with those medicines it may lower pressure too far.
It is not advised. In a 2006 trial of people who had recently had a heart attack, arginine did not improve their arteries or heart function, and the trial was stopped early after more deaths in the arginine group.
Not yet. Caltide's food data does not include arginine, so Caltide does not total it in the Nutrition tab.
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