Optimal Result: 74 - 196 µmol/L, or 7.40 - 19.60 µmol/dL.

Leucine, together with isoleucine and valine, are essential amino acids that are referred to as branched-chain amino acids (BCAAs).

Leucine is nutritionally essential and is required for formation of body proteins, enzymes and some hormones. Leucine itself has a hormone-like activity which is stimulation of pancreatic release of insulin. The branched-chain structure of leucine makes it very important for the formation of flexible collagen tissues, particularly elastin in ligaments. Leucine is relatively abundant in all protein foods.

Function of BCAAs:

– synthesis of enzymes

– transport proteins

– structural components of cells

Unlike other amino acids, BCAAs do not serve as precursors for bile acids or neurotransmitters, but are involved in:

– control mechanisms for neurotransmitters,

– muscle development and repair,

– and blood-sugar regulation.

– Leucine stimulates insulin production and promotes protein synthesis.

Although leucine is abundant in muscle tissue it cannot substitute for glucose in the fasting state, but is converted into other compounds that serve as an alternate source of energy for the body.

Low BCAAs are an indication of:

– chronic depletion from low protein intake

– poor digestion

– or increased utilization from chronic over-exercising.

What does it mean if your Leucine (Plasma) result is too low?

Leucine, an essential amino acid, was low in this specimen. Leucine is a branched-chain amino acid that is a common constituent of proteinspeptides and hormones. It also promotes wound healinginsulin releasefrom the pancreas, and is a component of elastin (ligaments).

– Low leucine can result from protein malnutrition, zinc deficiency (Zn dependent peptidase), or other gastrointestinal dysfunctions such as hypochlorhydria (aka achlorhydria). Food intolerances and malabsorptionmay be coincident with subnormal leucine.

– Low leucine can point to potential catabolism of skeletal muscle. Check 3-Methylhistidine to confirm this.

Subnormal leucine is unusual but can coincide with:

– deficient activity of digestive peptidases

– zinc deficiency

– pancreatic dysfunction

– or poor quality diet.

– Leucine can also be subnormal in hepatic encephalopathy (=decline in brain function that occurs as a result of severe liver disease), and absorption and uptake can also be deficient following intestinal bypass procedures.

What does it mean if your Leucine (Plasma) result is too high?

High fasting levels of leucine may be caused by a deficiency of vitamin B6elevated insulin levels, or excessive supplementation.

Leucine, isoleucine and valine are branched-chain structural amino acids whose catabolism requires multiple nutrient co-factors including:

– P-5-P (vitamin B6)

– thiamin (vitamin B1)

– riboflavin (vitamin B2)

– lipoic acid

– Coenzyme-A

– biotin (vitamin B7)

– magnesium

Branched chain amino acids are often elevated as a result of deficiency of B-6and/or B-1, or excessive supplementation with protein (eg. whey protein) or the specific amino acids for body building/exercise recovery purposes.

A more serious, but rare cause of branched-chain hyperaminoacidurea is known as Maple Syrup Urine Disease (MSUD) that results from an inheritedenzymatic defect. Symptoms of MSUD may be episodic with protein intake.

In infants and children MSUD symptoms include:

– vomiting

– irritability

– lethargy

– food refusal

– muscle hypertonicity

– respiratory

Convulsions and seizures may occur in acute cases. Individuals presenting with moderate branched-chain hyperaminoacidemia should be retested afterreduction in protein intake and supplementation with vitamins B-6 and B-1. Those with MSUD should pursue professional advice regarding the avoidance of foods that are high in branched-chain amino acids.

Understand blood, stool, and urine medical results from your labs.

10 000+ happy clients
100% satisfaction
★★★★★ customer support

Get 10% off of your first yearly or monthly plan.

Use promocode

Essential Plan


  • Monthly subscription
  • Instant interpretation
  • Use the free self-upload form
  • Additional charge for upload service
  • 2000+ biomarkers explained
  • Recommendations
  • Cancel anytime

Advanced Plan


  • Yearly subscription
  • Instant interpretation
  • We upload five reports for you
  • Use the free self-upload form
  • 2000+ biomarkers explained
  • Nutrition Recommendations
  • Online support
  • Cancel anytime

Own It For Life premium plan


  • No subscription
  • Unlimited access
  • Unlimited storage
  • Instant interpretations
  • We upload ten reports for you
  • Use the free self-upload form
  • 2000+ biomarkers explained
  • Nutrition Recommendations
  • Dedicated support

Healthmatters.io software for professional use.

Welcome to Healthmatters Pro.

Save time on interpreting lab results with the largest database of biomarkers online. In-depth research on any test at your fingertips, all stored and tracked in one place.

Learn More


We implement proven measures to keep your data safe.

At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.

General Data Protection Regulation (GDPR). HIPAA compliance for healthcare professionals
×

Understand Your Lab Result Now

  • Instant interpretation
  • 2000+ biomarkers explained
  • Science-based recommendations
  • Online support
  • Secure and private portal

Get 10% off with promocode:

;