avoid metformin if you are not on testosterone. It will kill testosterone levels.
Berberine is a huge favorite of mine now for the following reasons:
1) Works as well as Metformin without lowering testosterone
2) Lowers triglycerides, something Metformin does not.
3) Has a pretty significant anti-depressant quality to it.
4) Has some strong anti-inflammatory properties too.
ALA is a must. Period.
Also, eating a diet low in carbohydrate is simply hands down the best, if not the only way, to go about increasing sensitivity in a hurry.