Mast cells

Mast cells are immune cells found in skin, gut, airways and around nerves. When triggered, they release histamine and other substances. Much of the dermatology research on palmitoylethanolamide starts from its reported effect on these cells.

The evidence

• In one animal study, palmitoylethanolamide reduced mast cell degranulation in the ear after a local trigger by 35%, compared with 9% for saline.
• In a model of contact allergic dermatitis, the effect was blocked by a CB2 receptor blocker and was not blocked by a PPAR-alpha blocker. So this effect does not appear to run through PPAR-alpha.

A rat study in this database, De Filippis 2011, reported that palmitoylethanolamide reduced mast cell degranulation and nerve growth factor in an inflamed tissue model.

The caveats

Rankin and Fowler 2020 conclude that the studies clearly show an effect on mast cell function. They do not show how it happens.

One human trial on this site measured a related marker. Briskey 2023 reported a fall in plasma histamine in a subset of participants, while the main symptom score showed no difference from placebo.