Since copper peptides are naturally present in the body, they are highly compatible with skin physiology and rarely cause irritation
Your GP may arrange periodic blood tests to ensure B12 levels remain adequate, though clinical response is generally more important than specific blood values once treatment is established
(PubMed) Yang L, Calingasan NY, Wille EJ, et al
And I should mention, because I mentioned the ice bath, that of course pain threshold is something that can be built up, but it does seem that certain patterns of thinking can allow us to buffer ourselves against the pain response, and that should not be surprising
References 1 FDA Prescribing Information (Egrifta / Egrifta SV)Tesamorelin is a stabilized synthetic analog of GHRH (1-44)