Hi Peter and Bluetit,
Very interesting.
39 years ago when I was first diagnosed I went through the Type 2 meds, Chlorpropomide, Glibenclamide and finally Metformin. Spellings may be wrong as spellchecker says so but this is how I remember them. I was determined to make the best of it as I had wife and 2 young children depending on me. I responded well to each of these meds in turn but after a few weeks they worked less and less well. Fortunately for me the first finger tests had just become available - the original BM sticks - so I was able to track the weakening effect of each of these drugs. The point of this intro is that each time I reacted by cutting back on my carbs to between 20 and 30 grams per day. My memory pf those times is of snacks consisting of cheese and carrots, meals I guess were plenty of meat and green veg. I seemed quite healthy regularly running 30 miles a week and competing in local half marathons.
When I was moved on to insulin it seemed the best thing that had happened to me since becoming diabetic because I could now eat what I liked again just making sure I injected enough before eating. If one of you guys is down to 30 carbs I suggest you ask your consultant if you should be re-classified as type 2 requiring insulin which is what happened to me. It was really a life changer. I had resisted the idea for some time because I feared the action of the insulin and the hypos. in those days there were only one or two books aimed at newly diagnosed diabetics not like today when Dr Google leads you to sites like this with lots of people willing to help and share experiences.
With regard to the length of action of Metformin I had not realized it was over days. With insulin there are a range with different time periods form 4 to 36 hours. I am currently using one which has a theoretical time span of 4/5 hours but the evidence of my dexcom is that it goes more like 6/8 - one of the revelations that the device has brought to me.
Obviously managing Dawn Phenomenon is a lot more tricky for someone on metformin than someone on insulin, I imagine dose and meals timing are crucial but, given the time span that the drug works over, to have good control of it will need much experimentation. The trouble is that based on my experience few days are exactly the same as the one before even if the routine of meals and injections are the same. If your next HbA1c is good then perhaps best not to get to anxious about it. I have always had good results even though on most days I have gone above 12 mmol/l generally briefly.
My view of Formula Libre and dexcom is that FL is the ultimate logical development of fingerstick testing - but it is still a reactive system, you have to ask it the question, not practical when you are fast asleep. Dexcom is the biggest step forward in diabetic self management since the BM stick. It is proactive - it does not wait to be asked.
If as a type 2 you are unlikely to go hypo then the FL is probably a cost effective solution - particularly if you are self funding - but as I am definitely subject to hypos means dexcom is pretty well worth bankrupting myself for (still got the wife but kids are now independent and probably better off than me!)
Cheers,
Stroudie