L-Lysine and L-Arginine may promote growth hormone release

L-Lysine (or Lysine) is an essential amino acid for humans and is important for proper growth [1] and tissue repair [6]. It also plays an important role in the production of carnitine (nutrient responsible for converting fatty acids into energy) [1]. Most people get enough lysine in their diet, although athletes may need more. It is also taken by mouth to improve athletic performance.

Dietary Sources

Foods rich in protein are good sources of lysine.

That includes [1]:

• red meat,
• pork, and poultry,
• cheese,
• eggs,
• soybeans,
• fenugreek seed,
• certain fish,…

Dosage and RDA

Dosing has not been adequately studied, but beneficial clinical effects occur in doses ranging from 100 mg to 4 g a day. Higher doses may also be useful, and toxicity has not been reported in doses as high as 8 g per day. [9]

For adults ages 13 and older the recommended daily allowance is 12 mg/kg/day.

Lysine Benefits for Exercise

Lysine is found in abundance in skeletal muscle. It plays an important role in the building and maintenance of skeletal muscle tissue while also decreasing the rate of protein degradation in the body.

Muscle Mass

Muscle mass is determined by protein synthesis and protein degradation. Lysine (Lys) is considered to be essential for maturity in growing as animals fed with low-Lys diets were growing more slowly than those fed standard diets [10]. After changing to Lys sufficient diet, hormone levels changed which resulted in increased protein synthesis and suppressed protein degradation of skeletal muscles. Other animal studies [11] have also shown that oral administration of Lys to rats suppressed the rate of muscle protein degradation. Sato et at. [12] reported that Lys suppresses muscle protein degradation via the activity of autophagic-lysosomal system in part through the activation of mTOR and Akt in C2C12 myotubes.

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Lysine and Arginine

We have talked before about L-arginine and its effects on growth hormone release in combination with exercise and at rest. In this section, we will discuss the combination of L-Lysine and L-Arginine on human growth hormone (hGH) release. Suminski et al. [2] tested their effect in 4 trials in sixteen young healthy men. Trial 1 performed exercise and ingested placebo, trial 2 ingested 1,500 mg L-arginine and 1,500 mg L-lysine immediately followed by exercise, trial 3 same as trial 2 only without exercise and trial 4 no exercise and placebo. No differences in growth hormone levels were noted between the exercise trials. Growth hormone was increased in trial 3 where amino acids were ingested without exercise. Another study supplemented with 1,200 mg of L-lysine and 1,200 mg of L-arginine increased human growth hormone levels within 30 minutes and peaked after 90 minutes with its human growth hormone concentrations elevated up to 8 times greater than basal levels [3]. When 11 competitive weightlifters (aged 19-35) were supplemented with combined L-lysine, L-arginine and L-ornithine twice a day (2 grams each) there were no significant differences between serum human growth hormone levels on 24-hour level [4]. So, it seems that low dose amino acid supplementation provides no ergogenic value.

Exercise alone is a powerful human growth hormone secretion stimuli and these amino acids don’t seem to increase it further. However, at rest, they seem to increase growth hormone significantly.

Many bodybuilders consume amino acids before strength training in a belief that this will increase exercise-induced growth hormone release. We found no appropriately conducted study that would show that oral supplementation with amino acids prior exercise would further increase growth hormone levels.

Interestingly lysine competes with arginine for absorption and entry into cells [6].

Uses

Herpes Simplex Virus (HSV) – Cold Sores

Cold sores (or fever blisters) are caused by the herpes simplex virus (HSV) [14]. Lysine appears to be an effective agent for reduction of occurrence, severity and healing time for recurrent HSV infection. 312–1,200 mg of lysine daily accelerated recovery from herpes simplex infection and suppressing recurrence in 45 patients with frequently recurring herpes infection [8]. Another double-blind, placebo-controlled, multicenter trial by Griffith and colleagues [7] also reported fewer infections and significantly diminished severity and healing time. The possible mechanism of its inhibition of HSV growth is by knocking out arginine [6].

Other Benefits

There is one case report suggesting lysine may ameliorate angina [13]

Precautions and Side Effects

L-lysine in a diet is considered safe. Even relatively high oral doses of lysine are likely to be safe [5]. Minor side effects such as diarrhea, nausea, and abdominal pain, have been reported with lysine ingestion [5].

(Other common names: Lysin, L-Lysine Hydrochloride / Monohydrochloride / Acetylsalicylate, L-Lysine HCl, Lysine Acetate, Enisyl, (S)-2,6-Diaminohexanoic acid, L-2,6-diaminohexanoic acid)

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References