Tetrahydromagnolol (Magnolignan), a main metabolite of Magnolol, is a potent and selective cannabinoid CB2 receptor agonist with an EC50 of 170 nM and a Ki of 416 nM. Tetrahydromagnolol possesses 20-fold more selective for CB2 receptor than CB1 receptor. Tetrahydromagnolol is also a weak GPR55 receptor antagonist.