There are a lot of herbs that do a great job of controlling blood sugar. Fenugreek, bitter melon, juniper berry, bilberry leaf, green stevia, etc.
If you are pre-diabetic though you can probably get by without any hypoglycemics. Instead I recommend chromium polynicotinate (not picolinate)200mcg 3 times daily. Chromium opens up the insulin receptors that are closed in type 2 diabetes. It is available inhealth food stores for about $6 a bottle.
Also stay away from Sugar substitutes like Aspartame (Equal, Nutrasweet) and sucralose (splenda) which actually raise blood Sugar and stimulate weight gain.