Type 1 and Metformin

Hi, all. I've been T1 for 35 years.

My endo wants to put me on Metformin. I've been having dawn phenomenon/morning insulin resistance as well as spikes after exercise. His thought is that if we can suppress the liver dumps, my control may smooth out.

He wants to start me at 500mg morning and evening. Not only am I worried about daytime lows, but I'm really worried about nighttime lows. Suppressing the liver dumps overnights sounds like a dangerous thing to be messing with.

Does anyone do Metformin daytimes only? Does that even make sense?

Thanks in advance.

I'm also T1 for a similar amount of time I've been thinking about asking for this for myself. I read about other folks who only "spike" when they eat carbs, and I compare it to me, where I "spike" if I don't eat anything (dawn phenomenon) and "spike" if I eat protein or, well, anything.

Not having dawn phenomenon sounds even more appealing than not having a hole in my head :-)

I read about Metformin and the way it suppresses gluconeogenesis sounds way cool. But like you worry about my body's own defenses against hypos (liver dumps) being lost.

Metformin will not suppress but down-regulate the output of the liver depending on the metformin dosage. It sounds logical to me that you will need less basal insulin to cover the reduced output. It would be good to make the switch from Friday to Saturday to make some tests at night. In general I think that this experiment is really worth the trouble.

I am also Type 1, but for only 9 years. Last year my Endo put me on Metformin ER 500 mg with each meal because I have after meal spikes. I also have Dawn Phenomenon after having fasted all night. I can only speak for myself, but Metformin ER did level out my spikes and has helped a lot with the DP. However....I did find that I needed less basal insulin and I had to adjust my basal rates by about 15%. I don't know if my experience will help answer your questions, but I offer it for your reference. I do not take Metformin if I happen to skip a meal.

Interested to see how it goes. Please keep me posted on your results. I thought that metformin was a type 2 med. I've been having a similar pattern as you. Highs after I work out.

I had the same problem and my endo suggested I could try metformin if I wanted to...I've been on it for several months now and it seems to help. My insulin usage is down about 20-25% (I am taking 500 metformin ER 2X a day). The extended release form has less side effects... it takes awhile for your body to get used to it...you may have some digestive upsets when you first start. They suggest ramping up the dosage slowly.

I find it helped with the dawn phenomenon/overnight high basals I was using and also reduced spiking at meal times. IT seems to slow digestion down and I find I do not need to dose the insulin 15 minutes before eating anymore.

Do pay attention to your BG as you start as you may find you need to reduce your basal insulin and I:C to avoid going low.

P.S. I also lost about 5 lbs on it. You may find you are not as hungry when taking metformin.

for what its worth; in my case, metformin in sufficient doses is the only thing that will stop excess liver glucose release as well as liver dumps and dawn phen. I have watched this effect on cgms for last two years and science is out there. Salk and John Hopkins have all investigated this and reported on the effects. As indicated; if the dose up to strength in the blood is not sufficient - yes it will not down requlate the liver. John Hopkins did say there were folks this did not work on but for those they do; they have way for determining required dose.

I take my pills at every meal one hour before a meal as well as at 10:00pm and 12:00am. I do not find that large single shot doses work very well either and frankley useless.

I am a type 2 who is using insulin as well. I actually use a cgms to watch my body and operation and yes metformin can cause some lows under some curious circumstances. Basil insulin may help but did nothing for me.

As I am not a Doctor I cannot advise you, but according to some theories out there, metformin under sufficient doses ( 500 to 800mg) can cause the liver to reduce its output as well as liver dumps occurring under weird circumstances.

2192-Salk_metformin_data.doc (31.5 KB) 2193-metformin_hopkins_operation.docx (21.4 KB)

Another point here which creates this confusion about liver glucose not being down regulated by metformin is the general way the drug is prescribed.

Merformins effect this way is when metformin is up to strength in the blood. once that dose is reached - about 2 hours to get there, it lasts for about 1 to 3 hours before exhausted by body ( unmodifird incidently)

So if you take one big dose one a day of standard met , one only gets about 1 to 3 hours of control. I have watched this on CGMS for last 2 years and caveman machine before that. Timing and action predictable like a clock. Extended met may provide longer times. I do not use as it seems unpredictable to me.

You want to get longer periods of control; one needs to take more smaller doses sprnead around the clock. Residual met does not enter into this effect.

Metformin is used in T1 who may suffer who may be insulin resistant from weight gain,The increase in sensitivity does have the added effect of less insulin usage and there for your endo should advice you about amount of cutting down of units in your daly intake,I no in a test study i was reading insulin sensitivity increased from 0.86 +/- 0.33 x 10(-4)/min/(microU/ml) to 1.17 +/- 0.48 Noramlly 1.17 /- 0.48 x 10(-4)/min/(microU/ml and that massive increase.normally between 500Mg or 1000MG to 1500Mg is used split into 1 or x 2 or x 3 a day allowance to have with food,The other added benefit is a redction in HbA(1c)control,I no that british have used metoformin in use for adults with T1DM and have had great Success as a treatment.

Hey, Jims--the manufacturer says course of action 10 hours. Maybe your mileage varies?

I think this is more complicated. Metformin has three actions, improving insulin resistance, decreasing the absorption of carbs and decreasing the output of blood sugar by the liver. There may well be some short term effect, but I have never seen it. At usual doses, metformin reaches steady state concentrations within 24-48 hours, but generally it is thought to reach full effectiveness at in 4-6 weeks. Many people actually take metformin XR which is extended release which makes the timing even less pronounced. I have tried to stack my metformin at night to try control my Darn Phenomenon, but with little luck.

if one reads the spec sheets; one sees that the level in blood takes 2 to 2.5 hours to reach dose level. It has lasting power of the dose taken for one to three hours and leaves body at end of cycle for .5 to 1 hours. my experience is that is all that the liver pays attention too.

yes the doses do stay longer in other tissues as described but I find they have zero impact stopping excess liver glucose release. Insulin sensitivity is another ball of wax!

Regarding Dawn pheno; I do not know what you describe as stacking.

Min required dose (500 to 800mg for me) spread around clock - dose at 10:00 pm and 12:00am has resulted in my dawn phen shutdown for about 5 hours and as met leaves blood stream, liver pops out of cage to start hammering the glucose.

The longer one keeps the dosage the liver responds to up in the blood, the longer the liver is hauled back.

I have routinely saved insulin since hauling back liver glucose release means less insulin needed to stuff glucose in muscles.

Every time I do this my liver is caged. One large dose is useless and does not work.

Thank you for sharing experience.

While serum levels of the drug may reach full levels in 24-48 hours, numerous sources suggest that the effect of the drug does not reach full levels for weeks. I have tried to take most or all of my daily dose of 2.5g of metformin at night to address DP, but it just does little good. That is what I meant by stacking.

Three months is the norma;ty brian

As indicated, I find taking one large shot doesn ot work repeatedly. In fact many of times I was told by medical experts, - just take it in one large dose - it never worked.

for me, about 500 to 800 mg dose works and then take in the 2 hour sequence described for me and liver is always stopped in track.

In Fact I could run my watch by watching the 2.5 hour up time on digestion and immedately see the blood glucose drop after 2.5 hours and stop climbing for 2 hours till blood stream load of met worn off.

Here is older article from Diabetesnet.com talking about metformin and its uses. Some of the science articles are miserable to paw thru.

2191-metformin_article.doc (36 KB)

I'm glad that metformin works like this for you, it doesn't in my case (I take XR by the way). The drug information on metformin suggests that the effect is cumulative and it does not reach full effectiveness for weeks. You may certainly see some effects as you have, but the full effect, particularly on insulin sensitivity is suggested to be cumulative.


Thank you. Yes the data on insulin sensitvity issues do seem cummulative and I have no argument. Metformin has many effects.

Lab data and research data I see on metformin and on effigy work suggests data of aprox 2.5 hours from digestion to max dose level in blood. That dose lasts from minimum 1 hour to 3 hours. For me 2 hours. It exhausts in about 1/2 to 1 hour from that peak dose.

John Hopkins Childrens report did say the affect worked on some folks and others are not genetically pre-disposed.

Clearly, nobody should try this out without medical assistance , approval, guidance and a cgms for safety.

In my case, at no time did we read scientific journals and try this out. It was arrived by accident when 5 yeras ago I took my dinner met dose late at 12:00 midnight. BG in am was 187 instead of 238. Repeated this and found same result.

Next Doctor put another dose at 10:00 pm and the morning BG was 120 to 140 and repeatable.

Next scouted out all the research on metformin and shocked by what was found.

While the arguments are vehement about how met presently works; all data sheets and scientific articles admit they do not know how met really works and advance theories.

Even more bizarre is that met gets exhausted unmodified with no digestive products which really asks what is met really doing - Sinalling and or catalyst?

Best wishes and good luck.

Brian: I meant to add that:

a) in your case and anybody with working liver signalling that responds to blood insulin levels, one probably does not see this liver met signalling issue.

b) mine does not and demonstrated by fact on any required liver action, the liver in me is determined to shoot the whole liver buffer at my body - no exception. The only time this stops is in presence of sufficient metformin dose in blood - not residuals met in other tissues.

c) in fact my Doctor recommended I not let my BG drop sub 100 so that my BG cannot go sub 70 and force liver action adding glucose and forcing my glucose to 511 - max meter reading and then slide back to 278 to 311 as blood pumps the huge liver dump around the body. SO far only met seems to stop that nonsense in its tracks.

Given it has take 30+ years to finally get mess under control as well as fixing diet, eating, energy balance and exercise.

It may turn out that I am a special edge case of failure in this complex multi-organ-multi hormone system. My Doctor thinks so.

Looking at the reponse I get from some quarters; One might think I was down at the church nailing Luther's Treatis on the thick solid church door attacking the Dogma.(my concern is only that there may be alternate and valid theories and possibilities and other modes of failures)

Attacking me when numbers are exploding into the stratosphere world wide; suggest we need to shut down defending the heart felt dogma and current pet theories that do not seem to be solving the problem and start earnestly start working and solving this mess!

Thanks, Mayumi. I was looking for T1 feedback and this is very helpful. I'm on 17U a day basal so a 15% decrease would not be a massive change. I read some studies of T1's that say the expected decrease is from 0 - 25%.