Metformin is a prescribed medication to manage insulin resistance as it helps your body utilise the insulin your body is making better. The primary indication for prescribing metformin is as first-line therapy for type 2 diabetes  There is no evidence to suggest contraindications to be taken alongside prescribed metformin. However, you can consult your doctor regarding supplementation alongside prescribed medication. It's also important to note that both CoQ1 and metformin have potential GI side effects, so be aware of this if you have gut sensitivities.