Luteolin is a naturally-occurring flavonoid from colorful plants, and is known to be a natural mast cell stabilizer. A new study out by Dr. Theo Theoharides and team suggests it may help brain fog in patients with long COVID. His luteolin supplement is available from Algonot.com and his article is here.
Nutrition for POTS, MCAS, dysautonomia, autoimmunity and related conditions 