Monday, November 24, 2025

Leucine

Why leucine is good for you

Leucine is an essential amino acid which assists to regulate blood sugar and energy levels, production of the human growth hormone, wound healing as well as the growth and repair of muscle tissue.

Leucine can also assist in the prevention of the breakdown of muscle proteins that may occur after severe stress or trauma.

Important leucine facts

  • Leucine is part of the three branched chain amino acids (BCAA) – the other two are valine and isoleucine

Groups at risk of leucine deficiency

Deficiency of leucine is rare, but can occur in the following individuals:

  • People on low protein diets – people who are not eating enough protein foods may not get enough leucine in their diet
  • Vegans / vegetarian – people who are on a strict vegetarian diet may suffer from a leucine deficiency if their diet is deficient in protein

People in these groups at risk of leucine deficiency should talk to a medical professional about leucine supplementation before trying it.

Symptoms of leucine deficiency

Deficiency occurs in individuals who are deficient in dietary protein – symptoms are similar to hypoglycaemia and may include:

  • headaches
  • dizziness
  • fatigue
  • depression
  • confusion
  • irritability

Leucine and health

  • Phenylketonuria – leucine may be beneficial for individuals with phenylketonuria, which is a genetic disorder where the body cannot metabolise the amino acid phenylalanine

Talk to a medical professional about leucine supplements before taking them.

Leucine in food

FOODAMOUNT
Leucine
(mg)
Lean Round Beef, cooked
250g
6377
Lean Veal leg, cooked
250g
5585
Turkey breast, no skin, cooked
1/2 breast (200g)
4791
Snapper, cooked
1 fillet (170g)
3633
Canned tuna – in water
1 tin (165g)
3420
Clams mixed species
20 small (190g)
3416
Atlantic cod, cooked
1 fillet (180g)
3341
Chicken breast – no skin
1/2 breast (200g)
3210
Northern pike, cooked
1/2 fillet (155g)
3111
Yellow fish tuna, cooked
100g
2436
Lobster
1 cup (145g)
2359
Alaskan king crab
1 leg (172g)
2058
Blue crab – flaked
1 cup (118g)
1892
Ling, cooked
1 fillet (151g)
1688
Whiting, cooked
1 fillet (72g)
1374
Atlantic perch, cooked
1 fillet (50g)
970
Pastrami Beef
6 slices (57g)
722
Silken tofu – lite
1 slice (84g)
421
Egg white – raw
1 large (33g)
335
Spinach – frozen
1 cup (156g)
296
Chicken breast – oven roasted
28g, sliced
229
Seaweed – spirulina – raw
28g
144

Leucine recommended daily intake (RDI)

RDA135mg/kg body weight (infants)
42mg/kg body weight (children)
26mg/kg body weight (adult)
TOLERABLE UPPER LIMIT170-1100mg
TOXIC LEVELSNo information available

Leucine works best with

In order to balance a leucine supplement, it needs to be kept in balance by: 2mg of each of leucine and valine for each 1mg of isoleucine. Talk to your natural health practitioner to get the right balance.

Overdosage, toxicity and cautions for leucine

There has not been any consistent evidence that leucine supplements have any toxicity. Although it is known that a high intake of leucine may give rise to the disease pellagra and may increase the amount of ammonia in the body.

References

  • Osiecki H, Meeke F, Smith J, The Encyclopaedia of Clinical Nutrition – Volume 1: The Nervous System, BioConceps Publishing QLD 2004
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