Supplements deliver a concentrated form of allicin, which is the organosulphur compound responsible for the medicinal benefits of garlic, McClusky said. Some claims state that an allicin powder extract is the best form of supplement.ome say that taking garlic supplements can also help to prevent them and get rid of them more quickly. Allicin: Allicin is a sulphur compound similar to the one found in onions, and it could offer a host of health benefits.