Positives

• A long-hauler with CFS and MCAS reported that Vitamin C “lowers histamine levels,” describing significant relief from mast cell symptoms after incorporating it into their routine, and noting it was one of the few affordable interventions that made a noticeable difference Reddit.
  
  
• A patient described Vitamin C as helping with Long COVID burning sensations, inflammation, and restricted blood flow, sharing that it reduced their most persistent symptoms when taken consistently Reddit.
  
  

Negatives

• A long-hauler reported that Vitamin B12 and Vitamin C together made their symptoms “much worse,” experiencing increased burning sensations from ascorbic acid forms of Vitamin C Reddit.
  
  
• One patient who tried IV Vitamin C infusion therapy once a week for three months reported “no noticeable difference” in their symptoms, positive or negative Reddit.
  
  

Hurdles & Side Effects

• A patient with MCAS and hypermobility cautioned that Vitamin C can deplete copper, which may amplify hypermobility and create additional problems for patients with connective tissue issues Reddit.
  
  
• A long-hauler interested in megadose Vitamin C noted that the ascorbic acid form caused GI distress at higher doses, and that finding the right form (liposomal vs. acerola cherry vs. standard) required trial-and-error Reddit.