Lows on Metformin only

I'm having a low right now, am at 54 (3). I only take metformin. I thought that you weren't supposed to go low when you were only on metformin?

I've had other lows, but they've mainly been in the region of 67 and above and so I haven't worried about it.

Has anyone else had experience of low BS on metformin only?

Yes, I've had lows whilst taking Metformin only. I passed out because of low blood sugar once. I find I have to eat meals at regular times and have to have a little carb of some sort before exercise.

I think that sometimes your body just does funky stuff. My daughter, who unfortunately inherited my genes has hypoglycemia which is morphing into my non-standard T2. It is like her pancreas is trying to work right but isn't so it periodically miscalculates what it is trying to do and spews out a ton of insulin causing her to drop. Sadly, her BG is now in the diabetic range and the drs. don't listen to her. She is 21, extremely active and barely plump despite being on her feet all day plus nearly obsessive workouts at the gym her fasting are now sometimes over 120. She is also moderate carb and rarely eats bread, potatoes or pasta living mostly on veggies, tofu, seafood, chicken and fruit. Due to these lows, her A1C is like 4.5 so she can't be having problems, right?

Folks, this is not funky, this is only demonstrating the poor state of knowledge out there and understanding how metformin actually works.

First off; metformin when up to sufficient strength in blood stream actually signals the liver to cut off the volume injection port on the liver's buffer glucose output port. The liver also always releases a keep alive level all the time of glucose which as best as I can tell is always on and I have not seen the metformin affect.

If gut empty and you have metformin up to strength and body on idle, you usually do not see lows.

The fun starts with similar same conditions where you suddenly start exercising hard or your intestines decide to shove things along; there will be a sudden demand for glucose. If metformin in blood is clamping the liver's large injection port; the liver is prevented from shooting in an extra blast of glucose - munch the glucose tablets.

This story is not really properly reported as actual findings ( Jan 2013 10 years later)that prove metformin works by bypassing the ampk chain in liver and signalling liver to shut off excess glucose add to blood stream.

Generally this is not an issue as usually gut/intestines outputting glucose and exact timing to cause this low is rather unique but that said I watched this phenomina for a year and half and watched the excess liver glucose shutoff every time a proper dose of metformin came up to strength in blood. Ran like clockwork.
2.5 hours( 2 to 3 hours) up to strength and last 2 hours ( 1 to 3 hours)

so, have fun, be carefull and if you are experiencing lows from this - keep the glucose tablets handy to play artificial liver buffer while metformin has a tight grip on your liver.

Well it happened when I'd spent the last two hours sitting on the couch watching TV after breakfast. It definitely had nothing to do with exercise.

Jims, not disputing what metformin does. My daughter is unmedicated and her body has poor control. It is unable to accurately gauge what it is doing and is why she and other people with hypoglycemia bottom out despite taking no drugs to cause this. Perhaps Megans problem is actually not related to the met but is her body stuttering and having poor control of its actions.

I thought that with Metformin I am safe but no. I need to eat every 3 hours and more often if I walk. My low BS when I feel bad(weak , trembles,dizzy and luck of concentration is 80, so I guess everybody has his own low barriere.

Hi Trenia

The symptoms usually come with the drop in BS is quick, so even if you are still in a good range you can feel symptoms. You can be lower than 50 and not have symptoms if the drop has been gradual.

Metformin ER or regular? How much and do you split the dose? Are you eating low carb? Have they ruled out T1?

Metformin used to peak for me about 5 hours after I took it, and in theory that could cause a low. When I was misdiagnosed as a T2, eating low carb, and on insulin, the metformin would cause lows when it peaked because it made the insulin more potent (or cut back on the basal glucose my body produced).

I think the occasional 67 isn't an issue, and if you rarely bottom out at 54, it isn't the end of the world. Also, meters aren't exact.

I'm on regular, one pill with breakfast and another with supper. I'm trying to eat lower carb, but I guess average 100g per day (this is a big improvement, but still not where I want to be).

They haven't ruled out T1, but I think it's highly unlikely. I'm not on insulin at all.

I agree, it isn't major but it's more of a curiosity to me because I had heard that it was virtually impossible to go low when you were on metformin. I guess I was misinformed.

I stand on what I said based on actual Data from cgms that was consistently repeatable.


thank you


T1 in adults often has a slow progression. Mine took years. I was initially diagnosed as T2, and lowering carb intake while taking metformin probably bought me 2-3 years before I absolutely needed insulin.

I think Metformin can cause diabetics to go a bit low, but it is almost never life threatening. It also isn't as if non-diabetics never go below 80. Still, I'd probably want to get on Metformin ER to lessen the peaks and valleys and have a more steady release of the med.

Finally, consider taking vitamins while on metformin especialy B12. Google "B12 metformin" for more information.

Certainly you raise a good point. This would indicate liver is not properly supplying glucose when bg goes sub-70 or liver buffer is run down.

For ne ; it has been the metformin.

typically the data sheets on standard metformin show a 2 to 3 hour delay from ingestion until up to strength dose in blood. ER has a delayrd response so could be longer!

I never have lows. Metformin isn’t working very well for me

It may be your liver is working ok and signalling pretty good so that
metformin is not showing any improvement. ie you liver is not leaking!

So; on to other issues! Thank you for sharing and best wishes for good health.

thanks for the info, I take 2X 500 a day but I experience lows rather often as I like walking.

Walking helps burn out the glucose in the muscles and can under right circumstances cause lows. I have seen that on cgms and used candy to offset the burn.