Tier 4 — mechanistic

Stimulatory effect of glycine on human growth hormone secretion

Kasai K, Kobayashi M, Shimoda SI
Metabolism: clinical and experimental 1978 27(2):201-208

Bibliography

PubMed
PMID 622050
DOI
10.1016/0026-0495(78)90165-8
Funding
Funding was not specified in the indexed abstract; the full funding disclosure has not been verified.
Competing interests
The accessible abstract does not establish the authors' competing interests; absence of a statement is not evidence of no conflicts.

Study snapshot

DesignExploratory human intervention
ModelAdult humans
Sample19 nonobese controls and 12 partial-gastrectomy participants in the oral experiment; additional route comparisons
Intervention250 mL of 0.3 M glycine orally; separate intraduodenal experiments
DurationAcute hormone-sampling experiments
EndpointsGrowth hormone; Insulin; Prolactin; Blood glucose

What the study showed, in plain terms

An early physiological study found an acute growth-hormone response to glycine that depended on route and participant characteristics. It did not assess muscle growth, recovery or longevity.

Key findings

  • Growth hormone rose after oral glycine in the normal group.
  • Responses differed after gastrectomy, intraduodenal administration and in diabetes.

What this study can and cannot tell us

Acute hormone release is not a clinical benefit and does not establish sustained anabolic effects.

Historical uncontrolled physiology cannot define a modern supplement regimen.

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Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction