Glycine and its Effect on the Growth Hormone

Glycine and its Effect on the Growth Hormone

Glycine is an amino acid with properties as a natural Growth Hormone enhancer.

What is a Growth Hormone?

A growth hormone is a neurohormone secreted by our pituitary gland in response to a chemical stimulus sent by our hypothalamus in the form of the neurohormone GHRH.


Figure I. Simplified mechanism of growth hormone synthesis.

Throughout life, our bodies undergo changes in the growth hormone secretion profile, with children and young adults having the most intense growth hormone pulses, especially during sleep.

Pattern cycles 24g hgh

Figure II. 24-hour pattern of growth hormone secretion in young and old (up and down, respectively), women and men (left and right, respectively).

Over the years, growth hormone production decreases, which has been associated with:

  • Muscle and bone mass losses (osteo-sarcopenia).
  • Increased visceral fat.
  • Decreased motor function.
  • Alterations in cognition (such as problems with concentration and memory).
  • Sleep disorders (which in turn adversely affect endogenous growth hormone production).


Figure III. Sylverster Stallone, an actor who has been reported to go to an anti-ageing clinic to use growth hormones to cope with the effects of ageing.

The growth hormone is not only considered an anabolic and lipotropic hormone, but also a genuine “anti-ageing” hormone that is currently being widely used in American clinics by public figures we are all familiar with..

Glycine and the growth hormone, is there a relationship?

The relationship between the growth hormone and large concentrations of amino acids has been demonstrated on numerous occasions.

The amino acids that have the greatest capacity to permeabilise the blood barrier that covers and protects our brain seem to have the ability to induce a strong response in the pituitary gland to secrete a pulse of growth hormone, although we don’t know the mechanisms through which it does so (Chromiak and José Antonio, 2002).

I’ve already discussed the response of another amino acid, ornithine, on the natural production of growth hormone in this article .

We could therefore say that there are amino acids with the capacity to act as growth hormone secretagogues in a natural way.

Influence of Glycine on the GH

The first studies evaluating the effects of glycine on growth hormone secretion were in vitro and animal model trials, which showed promising results in the 1960s and 1970s.

In the late 1970s, experimentation began in humans, after verifying that it was completely safe to use glycine to induce a pulse of growth hormone.

The pituitary response to exposure to glycine administered by intravenous infusion (injected by IV) was investigated.

The results were consistent with what was observed in animal models.


Figure IV. Growth hormone secretion curve after administering 4, 8 and 12g of glycine.

After glycine administration, the growth hormone reached a peak concentration of around 90 minutes, and the response was dose-dependent.

12g exerted more effects than 8g and these more than 4g.

Glycine is also an amino acid to which the pituitary responds by increasing growth hormone production.

But… Could this be achieved by oral, not intravenous, consumption?

Glycine powder and the Growth Hormone

In 1978, Kasai et al demonstrated that oral administration of 22g of glycine increased growth hormone concentrations by up to 264% after 120 minutes, very similar to the peak concentration in studies with intravenous administration.

Glycine graphic

Figure V. Growth hormone secretion curve after administering glycine at a concentration of 0.3M in 250ml of water orally.

The authors showed that despite an almost threefold increase in growth hormone concentrations (secretion pulse), neither insulin resistance indices nor prolactin secretion (a hormone secreted in the same gland) changed significantly.

Proving, therefore, that the use of glycine was safe and effective for increasing the natural production of the growth hormone in healthy humans.

This, together with the positive effects of this amino acid on sleep quality, makes it a great idea to use before sleep to improve nocturnal GH secretion, especially in adults from their late twenties onwards, when our concentrations begin to drop significantly.

Growth Hormone Decline Graphic

Figure VI. Decrease in natural growth hormone production throughout life.

Don’t forget to check out our Glycine Powder to take advantage of these benefits!

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About Alfredo Valdés
Alfredo Valdés
He is a specialist in metabolic physiopathology training and in the biomolecular effects of food and physical exercise.
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