I forwarded an article “Common diabetes drug may work by changing gut bacteria, study finds” to a reader and he responded:

“This is fascinating Ken, thank you. I belong to untold numbers of CFS and Lyme Facebook groups, newsletters, forums, etc. Many of them talk of Metformin as being the biggest and best “new thing” out there for treatment. Once again it seems that all roads lead to the microbiome…”

I am opposed to trying random “new things” but very much in favor of trying “new things” that the model that you are using would predict to help. With the microbiome model, I have had a very good batting average 🙂 .

What do we know about Metformin?

Metformin alters the gut microbiome of individuals with treatment-naive type 2 diabetes, contributing to the therapeutic effects of the drug [2017]. [Full Text]
- “Earlier studies have shown an association between metformin
  and the abundance of Akkermansia muciniphila and between
  
  A. muciniphila and improved metabolic features in mice and humans” Very Good! See this post on Akkermansia and this post on Chronic Lyme Microbiome.
- “After correction for FDR, we found that the PTR of only one bacterial species (Bifidobacterium adolescentis) was significantly increased by metformin”
Metformin Is Associated With Higher Relative Abundance of Mucin-Degrading Akkermansia muciniphila and Several Short-Chain Fatty Acid-Producing Microbiota in the Gut [2017].
“Akkermansia muciniphila (12.44%±5.26%) and Clostridium cocleatum (0.10%±0.09%) abundances increased significantly after metformin treatment” [2014]

Bottom Line

The known shifts for metformin appear to be beneficial for CFS/Lyme patients with no reported negative shifts. I suspect that it will likely improve some subset of symptoms (which ones are unknown). It would be nice to see a formal study done and published for CFS/FM/IBS.

It is reported to have some side effects:

“Metformin can rarely cause a serious (sometimes fatal) condition called lactic acidosis. Stop taking metformin and get medical help right away if you develop any of the following symptoms of lactic acidosis: unusual tiredness, dizziness, severe drowsiness, chills, blue/cold skin, muscle pain, fast/difficult breathing, slow/irregular heartbeat, stomach pain with nausea, vomiting, or diarrhea.” — of course, lactic acidosis is suspected to be a significant part of CFS…

On Facebook, a reader wrote ” I took metformin xr for my diabetes and it ripped me up!! Killed me with my IBS, to the point that I had to stop taking it.“

Farhan Yazdani 2:20 pm on August 22, 2017

Hello
Your comments are most interesting
I have Lyme disease under treatment and stopped associating Metformin that I used for a type 2 diabetes because of severe muscular pains.

It has now become apparent that this muscular pain is not due to lactate acidosis but to a Herxheimer reaction.

This can mean that the antibiotic or antimslarial capacities of metformine are efficient on Lyme.

I have now started associating a lower dose of Metformine to my treatment.

It would be interesting to seek invitro studies of anti biotic effect of metformine on Lyme coinfections.

Your comments would be appreciated
Larry Depuy 10:44 pm on September 25, 2019

I followed a blog when XMRV was thought to cause ME/CFS. It was a red herring, but a few people tried Viread. They reported feeling much worse for about 10 days and then improved. I too had a Herxheimers like reaction for about 10 days and then my health improved dramatically. I still had symptoms and now after having ME/CFS for over 26 years and at 71 years of age I am in decline. I have tried to get my dr. to prescribe Metformin to no avail. Doctors don’t like to prescribe off label.
brad 9:43 pm on January 10, 2020

Larry,

You can get a generic Metformin without a prescription through reliablerxpharmacy. They have very shady purchase rules and shipping takes a month but they are legit. I hope it helps you.