Positives

• Small fibromyalgia studies suggest 5-HTP at 50-300 mg/day may improve symptoms including pain, stiffness, anxiety, and fatigue, though larger high-quality trials are needed for confirmation Health Rising.
  
  

Negatives

• One reviewer wrote: “I had high hopes for this supplement and must say it didn’t work for me. I had stomach cramps, fatigue, and an overall sense of anxiety. Unfortunately, a waste of money for me” Drugs.com.
• A patient started waking at 3 a.m. with sweating, elevated heart rate, vivid bad dreams, tension headaches, severe anxiety and depression after starting 5-HTP for sleep Drugs.com.
• Patients are commonly warned not to combine 5-HTP with SSRIs or MAOIs because of its known potential to cause serotonin syndrome Memorial Sloan Kettering.

Hurdles & Side Effects

• 5-HTP can cause serotonin syndrome when combined with SSRIs, SNRIs, MAO inhibitors, tramadol, or triptans — a real concern given many Long COVID patients take antidepressants for overlapping mood or pain symptoms Medical News Today.