Subcutaneous injection bypasses all of these barriers except plasma half-life, which for unmodified small peptides is generally very short (minutes to low hours, based on class-level pharmacokinetic data for similar unmodified peptides)
J Med Food 2014, 17 (2), 254261
Beneficial effects of plant oils supplementation on multiple sclerosis: a comprehensive review of clinical and experimental studies
~ AlphaMD You've probably heard whispers in the gym or seen the Reddit threads: there's a "banned" steroid out there that works better than regular testosterone replacement therapy, it's supposedly safer, and somehow it's completely legal
Other than patients who have had their stomachs bypassed, there is also an autoimmune condition known as pernicious anemia that leads to a deficiency of intrinsic factor, lack of ability to absorb vitamin B12 and therefore poor availability of cobalamin (vitamin B12)