why semaglutide is bad What the Dark Side of Semaglutide? GLP-1s 101: What the science

Design considerations for a pilot trial using a novel approach for evaluating smoking-cessation medication in methadone-maintained smokers

Summary: Feeling worse after a B12 injection typically reflects your body adjusting to replenished vitamin levels, triggering metabolic processes that may temporarily cause fatigue, headaches, or injection site discomfort

291-311.[DOI] 31

Busam KJ, Kutzner H, Cerroni L, et al

Otherwise, you might accidentally hit a muscle or blood vessel, which can be painful and cause bruising

That does not mean every study will show the same pattern, but it does explain why dose escalation and tolerability are often discussed together