Curcumin, I think in Asia, vastly larger doses than 3,000mg are taken in foods like curries. I take 1,000mg per day, I buy it from the USA since I have not found a UK source at that dosage. It is relatively cheap and i am sure 3,000mg is safe. I have done searches and you will find higher doses have been trialled successfully. I tried a trial mof 4,000 mg per day, but did not find much improvement, so stuck to my present dosage.
Ron