Do "hoodia gordonii" patches work safely for appetite supperssion?

No formal studies. Try these instead: water, organic vegetable broth, green leafy vegetables, natural pickles, apples are great to fill you up so you dont feel hungry and they are very low in calories.
Maybe. Hoodia gordonii has been used for years as an appetite suppressant. While it is safe, there is no good evidence to suggest that it works.