The question of whether peptides expire becomes irrelevant if they are frozen first
All references are to controlled laboratory studies this is not medical advice and these findings do not constitute evidence of therapeutic efficacy in humans
As for most other enzymes of the pathway, SIR may be persulfidated, but neither the cysteine affected nor the effect on activity have been explored (Figure 2 and Supplementary Table 2)
[DOI] [PMC free article] [PubMed] [Google Scholar] 32.Nakasaki M, Yoshioka K, Miyamoto Y, Sasaki T, Yoshikawa H, Itoh K: IGF-I secreted by osteoblasts acts as a potent chemotactic factor for osteoblasts
They are slightly more expensive, per serving, than most powders, but the convenience might be worth it for some