Positives

• In refractory interstitial cystitis cases, intravesical DMSO produced response rates of 60-70% by week 8-12, with patients describing meaningful pain and frequency improvement, per a PMC real-world Japanese registry.
  
  
• Small case series suggest patients with peripheral neuropathy or post-thoracotomy nerve pain notice analgesic effects from topical DMSO, per Memorial Sloan Kettering's integrative medicine review.
  
  

Negatives

• A 2013 Cochrane review concluded the evidence for topical DMSO in complex regional pain syndrome is very low quality, with patients seeing no advantage over placebo in a Drug and Poison Information Centre review.
  
  
• Patients commonly describe a strong garlic-like body odor and breath, skin irritation at the application site, and rare reports of peripheral neuropathy when combined with NSAIDs, per a PubMed case report on DMSO and sulindac neuropathy.
  
  

Hurdles & Side Effects

• DMSO is FDA-approved only for intravesical use in interstitial cystitis, leaving Long COVID nerve-pain patients dependent on industrial-grade products with quality concerns, per the same Memorial Sloan Kettering review.
  
  
• DMSO is a powerful solvent that drives any contaminant on the skin into the body, so patients have to scrupulously clean the skin and avoid concurrent topicals, per a Herbal Mana DMSO usage guide.