Growth hormone subcutaneously or intramuscularly?

Growth hormone belongs to the group of basic hormones of the anterior pituitary gland.

Tropic pituitary gland hormones include:

  • thyrotropin (TSH),
  • corticotropin (ACTH),
  • Gonadotropins (LH and FSH).

The effector hormones of the anterior pituitary gland are:

  • somatotropin (better known as growth hormone, somatotropic hormone),
  • melanotropin (skin pigmentation),
  • prolactin (regulates milk secretion, in excess is the cause of many serious disorders, e.g. libido, potency disorders).


Wilson DM et al. checked the response to subcutaneous or intramuscular GH administration in 20 children with growth hormone deficiency. None of the children received growth hormone for at least 2 weeks before the experiment.

Later 11 of them received subcutaneous injections and 9 intramuscular injections. Growth rate and levels of growth hormone antibodies were determined before and after 6 months of therapy.

Effects of Growth Hormone
Effects of Growth Hormone

IGF-I levels tripled in both treatment groups after 4 days of growth hormone injections, while IGF-II levels almost doubled, with no significant difference between the groups receiving GH intramuscularly or subcutaneously.

After 6 months of therapy, there was no significant difference in growth rate and only 2 patients developed antibodies to growth hormone. Both patients and their parents preferred the subcutaneous GH injection method.

An identical increase in IGF-I and IGF-II levels after a short cycle of subcutaneous or intramuscular injections of growth hormone, similar growth rates, low antibody production frequency, and preference for the subcutaneous route that GH can be successfully administered subcutaneously

Russo L. et al. compared subcutaneous or intramuscular administration of human GH (hGH) in the treatment of GH deficiency. Peak and mean hGH plasma levels of patients were similar after subcutaneous and intramuscular injection of the initial dose (0.1 U / kg) of hGH.

Maximum hGH concentration occurred after 2 hours in both groups. The growth rate after the HGH injection cycle and the change in growth rate at 3-month intervals were similar in the subcutaneous or intramuscular administration groups. After 9 months, most patients preferred subcutaneous rather than intramuscular injections.

The number of hGH antibodies was similar in both groups. Subcutaneous growth hormone administration is an effective and safe treatment for growth hormone deficiency. Lipoatrophy, which was rare at the injection site, can be eliminated by regularly changing injection sites.


Both rhGH and hGH can be administered subcutaneously and it is an effective method of combating GH deficiencies in the body.