Experiencing itchy, red welts after your peptide injections? You're not alone, and the peptide itself usually isn't the problem. The real culprits? Histamine release, mast cell activation, gut imbalances, hormonal shifts, or Vitamin B12 Skin Rash TikTok How to Treat a Semaglutide Injection Site Reaction Vitamin B 12 deficiency is common in strict vegetarians, elderly on medications to reduce acidity, and if you have malabsorption syndromes. , Symptoms: , Tingling , Numbness , Fatigue ,