While topical formulations have long been a staple, injection-based use introduces a fundamentally different approach that penetrates deeper and potentially produces more pronounced results
PhamVFehlbaumSSeifertNRichardNBruinsMSybesmaWet alEffects of colon-targeted vitamins on the composition and metabolic activity of the human gut microbiome- a pilot study
HGH binds the GHR on hepatocytes, activating the JAK2/STAT5 signaling cascade and stimulating transcription of the IGF-1 gene, producing 70% of circulating IGF-1
These effects on body composition were recently confirmed by Elkind-Hirsch et al
You might also notice more headaches, irritability, or even mouth sores
Therefore, metformin appears to affect the microbiome, and could potentially exert some of its chronic pharmacodynamic effects in this manner, and an individuals metformin tolerance may be influenced by their microbiome