# Metformin

Category: Drugs & Compounds

Also known as: biguanide

Metformin is a biguanide drug whose fundamental mechanism, according to Ray Peat, involves poisoning the mitochondria so that cells are forced to waste glucose by converting it to lactic acid. Peat traced its lineage to the earlier drug phenformin, which was removed from the…

10 passages · 3 authors · 2014–2025 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/metformin

## Synthesis

**Metformin** is a biguanide drug whose fundamental mechanism, according to Ray Peat, involves **poisoning the mitochondria** so that cells are forced to waste glucose by converting it to lactic acid. [Source 2, 6] Peat traced its lineage to the earlier drug phenformin, which was removed from the market in the 1950s and 60s because it was killing a very high proportion of users through **lactic acidosis** by rendering mitochondria unable to oxidize glucose—the very problem at the core of diabetes. [Source 2, 6] Metformin was introduced as a reputedly safer successor, but Peat noted that even on PubMed one can find over a hundred articles warning about its production of lactic acidosis, and that it occasionally causes dangerously fatal lactic acid edema. [Source 2, 6] He described the drug’s apparent benefits as “surprising and perverse,” acknowledging that while it does not kill everyone quickly, it works partly through this mitochondrial impairment, though it may also have some slightly protective *anti-inflammatory effects*. [Source 3, 6]

Peat argued that metformin’s glucose-lowering action is a cosmetic masking of the underlying pathology. He explained that the drug lowers blood sugar in proportion to how fast it is wasting glucose, a process that takes the form of lactic acid production. [Source 1] He situated this within a broader critique of the diabetes treatment paradigm, noting that the death rate from diabetes actually increased after the introduction of insulin, and that the myth that sugar causes diabetes was sustained to support treatments like insulin and later the “very toxic glucose waster” phenformin and its successor metformin. [Source 1, 8] Peat also expressed skepticism about metformin’s promotion as an anti-aging drug, suggesting its mechanism involves blocking protective functions and wasting cholesterol, which he saw as a perverse effect since cholesterol plays a protective role against the toxicity of **polyunsaturated fats (PUFAs)**. [Source 3]

Georgi Dinkov has extended this critique with mechanistic precision, identifying metformin as an inhibitor of **Complex I of the electron transport chain (ETC)**, which directly causes the lactic acidosis risk that is 30%+ lethal even with emergency treatment. [Source 10] Dinkov has written that the drug’s touted benefits are largely attributed to its activation of the enzyme **AMPK**, a mechanism it shares with endurance exercise, fasting, and caloric restriction, which massively increases *fatty acid oxidation (FAO)*. [Source 5, 10] He argues that this increased FAO worsens insulin sensitivity and that stopping metformin after prolonged use results in an exacerbation of diabetes pathology compared to patients who never took it, making the drug a “Trojan Horse” that masks symptoms while ruining systemic health. [Source 5, 10] Dinkov has also highlighted that metformin’s AMPK activation increases the expression of **myostatin**, the primary negative regulator of muscle growth, leading to muscle atrophy and a consequent tanking of the resting metabolic rate. [Source 5]

Danny Roddy and his co-hosts have observed the drug’s practical consequences in the health community, noting that metformin’s gut-wrecking side effects and its role as a mitochondrial complex blocker have led many to abandon it, though they predict it will cyclically return to vogue. [Source 7] They have also pointed to the rationalization required to continue prescribing metformin when a patient’s fasting blood glucose nearly doubles, framing it as a dangerous failure to understand that the drug is not addressing the underlying insulin resistance. [Source 4] Dinkov has further warned that metformin promotes cancer growth by increasing lactate and FAO, contrasting it with therapeutic anti-lactate measures like baking soda. [Source 9, 10]

## People also ask

### How does metformin lower blood sugar according to Ray Peat?

Peat argued that metformin poisons the mitochondria, forcing cells to waste glucose by converting it to lactic acid, so the blood sugar drop is proportional to this wasteful process rather than a genuine metabolic correction.

### Why is metformin linked to muscle loss?

Georgi Dinkov explained that metformin activates AMPK, which increases myostatin expression—the primary negative regulator of muscle growth—leading to muscle atrophy and a lowered resting metabolic rate.

### What happens to diabetes when someone stops taking metformin?

Dinkov warned that stopping metformin after prolonged use results in an exacerbation of diabetes pathology compared to patients who never took it, because the drug masks symptoms while worsening insulin sensitivity through increased fatty acid oxidation.

## Related concepts

- [Insulin](https://bioenergeticoracle.com/md/concepts/insulin/index.md)
- [Butter](https://bioenergeticoracle.com/md/concepts/butter/index.md)
- [Coffee](https://bioenergeticoracle.com/md/concepts/coffee/index.md)
- [Diabetes](https://bioenergeticoracle.com/md/concepts/diabetes/index.md)
- [Glucagon](https://bioenergeticoracle.com/md/concepts/glucagon/index.md)
- [Gluconeogenesis](https://bioenergeticoracle.com/md/concepts/gluconeogenesis/index.md)

## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — #43 - All things hormones, metabolism and health with Dr Ray Peat & Emma Sgourakis

Ray Peat · Interview · Apr 4, 2021

> **Kitty Blomfield:** Ray, just something that I've noticed, people will message me on Instagram saying that they've been diagnosed with, and this relates to sugar, with type 2 diabetes or PCOS and their doctors put them on metformin and it seems to be becoming more of a regular thing. Could you talk about that?
>
> **Ray Peat:** Yeah, the insulin in the 1950s, they were already seeing that possibly because it was made from pig pancreas, but it was turning out to be killing. The death rate from diabetes increased after the introduction of insulin, oddly. So people were realizing that insulin wasn't doing anything for public health. And they first introduced a chemical that lowers the ability to make energy from glucose. And that caused it to be wasted. And so it would lower your blood sugar in proportion to how fast you're wasting it. But after 10 or 15 years, that was taken off the market because the wasting process of the blood glucose took the form of lactic acid and acidosis was killing more people than the diabetes. But metformin came on the market when the previous closely related chemical was taken off the market. And now it has become sort of a wonder drug that they're using for everything. even though now and then there's a publication saying that it can cause lactic acidosis the way its predecessor did.

### Source 2 — Diabetes Type 1 KMUD the Herb Doctors 2014

Ray Peat · Interview · 2014

> **Herb Doctor:** OK, so again, you’re pointing the finger, blaming the free fatty acid liberation and the oxidative damage that occurs from that.
>
> **Ray Peat:** Yes, and the unsaturated fatty acids happen to create a vicious circle, because they create stress, and the stress activates the stress hormones which provide…( in the normal process of providing fat from the tissues as emergency fuel)… they liberate more of the unstable polyunsaturated fats, creating more free radical damage, creating more stress, liberating more fats, and so on. Where the purely saturated fats, when liberated, tend to turn off those stress hormones.
>
> **Herb Doctor:** ok, so another good reason yet again to avoid the liquid oils, and avoid the fish oils and all the other oils that basically are very unsaturated because they are unstable, promote oxidation and all the ,stress response and tissue damage therein?
>
> **Ray Peat:** Yes.
>
> **Herb Doctor:** ok, I just want to mention one of these drugs medications that I know quite a few people have been on, and probably are still using, amongst others, but metformin as a diabetes medication?

### Source 3 — One Radio Network: Ray Peat with Patrick Timpone — July 18, 2022

Ray Peat · Interview · Jul 18, 2022

> **Patrick Timpone:** Oh, I see. Well done. Here's one for you from Trent. Life Extension promotes the drug metformin as an anti-aging drug with many health benefits. What is your opinion of their recommendation, metformin?
>
> **Ray Peat:** Metformin?
>
> **Patrick Timpone:** Yeah, metformin.
>
> **Ray Peat:** I think... It's possibly doing something good by blocking, apparently, good functions. But the basic mechanism is blocking what you would think is a protective for progesterone use, but still the effect is to protect against PUFA just as much as against cholesterol.
>
> **Patrick Timpone:** So that's the anti-aging potential benefits protecting against PUFAs?
>
> **Ray Peat:** Yeah, by wasting cholesterol, it seems to also take down cholesterol.
>
> **Patrick Timpone:** I see. And we don't necessarily need to do that or want to take down cholesterol, do we?
>
> **Ray Peat:** No, but everything about metformin seemed sort of surprising and perverse because it's one of the original anti-diabetic drugs that always impaired the mitochondria and ended up increasing lactic acid. and killing people more than protecting them. More than protecting. So they found one of these diabetes drugs that turned out not to be more deadly than the disease. And so although it does occasionally Sometimes it's very dangerously cause lactic acid edema. The average benefit seems to be good.

### Source 4 — BV #6: Glucose Goddess, Gabrielle Lyon, & Dr. Boz: The Truth About Blood Sugar and Macros

Danny Roddy · Interview · Jan 30, 2025 · https://www.youtube.com/watch?v=urB5dTcJ_Ao

> **Jay Feldman:** people mike i forgot about this but a little bit later she says some people just need medication that's that's what she says for insulin resistance some people just need medication so you can continue to reduce the eating window and eat less volume on your carnivore diet but some people still just need the metformin
>
> **Danny Roddy:** you know i'm gonna name this the carnivore insulin resistance echo and i'm gonna write a book about it and i'm gonna be a millionaire so this is fantastic this is really
>
> **Mike Fave:** good this is grade A Olympic level mental gymnastics and rationalization and a clear lack of understanding of the mechanisms to be like okay maybe this person who's Presumably his blood glucose handling is significantly worse because he hasn't had any carbohydrate and fasting insulin or fasting blood glucose levels have increased significantly, right? So I presumably insulin levels would be lower since there's no carbohydrate intake. And then the blood sugar levels are almost doubled because they're saying 60 to 80 and now we're at like 114. So if he was starting around 60, that's almost in the 60 point increase. I don't know. If you had any intervention in a trial that was looking at that, they would probably stop the trial instead of wax the idea that there's just this really long lag effect and that the insulin resistance is just... The metformin's not working because the insulin resistance is just so bad. that it just takes it more than a year for the metformin to start working. I haven't seen a pharmaceutical company try to make that argument yet in a paper. That's like a really high level of rationalization.

### Source 5 — Top diabetes drug Metformin causes muscle atrophy by activating AMPK/myostatin

Georgi Dinkov · Article · Dec 7, 2024 · https://haidut.me/?p=2724

> It does lower blood sugar, but that was recently discovered to be due to its inhibitory effects on gluconeogenesis and not due to AMPK activation or increased FAO. Worse, the increased FAO due to metformin would be expected to worsen insulin sensitivity, and multiple studies have confirmed that stopping metformin after taking it for a while results in exacerbation of the diabetes pathology compared to other diabetic patients who did not take metformin at all. So, it is definitely starting to look like metformin is not only not the miracle drug we are being told it is, but is a very dangerous “Trojan Horse”- i.e. masking the symptoms of diabetes, while ruining systemic health and all but ensuring not only worsening diabetes in the future, but possibly even getting cancer in the process. If all that was not enough to change people’s mind on metformin, the study below may add more fuel to the fire. It looks like that not only is metformin potentially detrimental to metabolic health, but its primary target – AMPK activation – seems to lead to muscle atrophy by increasing the expression of myostatin (the primary negative regulator of muscle growth). As most of my readers know, lean muscle mass is the primary regulator of the resting metabolic rate (RMR) and losing muscle mass is just about the worse outcome a person can hope for from a drug, diet or exercise regimen as it would tank their RMR. This has already been corroborated by the (in)famous studies that looked at participants in the “Biggest Loser” (what an apt name) contests. All those people lost a lot of weight through fasting and “endurance” exercise (i.e. AMPK activation), but it turned out that most of their weight loss was from muscle, which resulted in those people’s metabolic rate essentially halving (due to the grueling weight loss regimen) and thus regaining ALL of the weight they lost even while maintaining a reduced calorie diet. Well, it looks like metformin is a great mimetic of the “Biggest Loser” regimen and the muscle loss it induces probably explains a good deal of the lack of long-term benefit from using the drug. Wait, what about fat loss, considering metformin increases drastically FAO by increasing AMPK?

### Source 6 — Diabetes Type 1 KMUD the Herb Doctors 2014

Ray Peat · Interview · 2014

> **Ray Peat:** Yeah, phenformin was the first form of that, that was used widely in the 50’s and 60’s. But it was killing a very high proportion of people: they were dying much earlier than they would have with no treatment at all. It was causing lactic acidosis, by causing the mitochondria to be unable to oxidize glucose. Which is exactly the problem of diabetes. So that got a bad reputation, and it was replaced by metformin which was reputed to not cause lactic acidosis. But even on pubmed if you look up metformin and lactic acid, you’ll see, I don't know, there must be more than 100 articles warning about the production of lactic acidosis with this standard very common treatment. And, it works, where it works, partly by poisoning the mitochondria, so the cells are forced to produce lactic acid. And so it lowers the blood sugar by wasting the glucose, turning it to lactic acid. But it also has some other effects which accounts for why everyone doesn't die quickly from lactic acidosis; apparently it has some slightly protective anti-inflammatory effects.
>
> **Herb Doctor:** I wanted to also let you get into the benefits of sugar; we have done several radio shows on how good and how beneficial sugar is for the organism. And the same with salt. And we keep getting validated slowly but surely with reports of that same thing in the press where, as before, it was pretty well maligned. So we understand there are a lot of protective effects of sugar confers to the organism from the cellular range standpoint. What are the beneficial effects that sugar have when you look at it from a diabetic perspective?

### Source 7 — BV #1: Bryan Johnson’s Longevity Diet, How Stress Affects Our Cells, & Whether Glucagon is Evil

Danny Roddy · Interview · Sep 19, 2024 · https://www.youtube.com/watch?v=5tXXW85Sb4o

> **Mike Fave:** Plus, metformin has a side effect of like wrecking your gut when you first start taking it. Like it will make you run to the bathroom, which is why like A-carbos plus metformin plus all of these things, like I couldn't imagine. Like I couldn't imagine this not... causing some type of discomfort plus eating like a ridiculous amounts of beans and nuts
>
> **Danny Roddy:** yeah metformin went the way of rob wolf's uh fish oil calculator i think people realized that it was damaging so they stopped doing it but the funny thing about the health world is stuff will come back into vogue later so maybe in eight months or something a lot of these same people will start talking about metformin again So what else is there to dissect from his supplement regimen?
>
> **Jay Feldman:** Well, he's taking fish oil, you know, no surprise there. We kind of talked about the N-acetylcysteine.
>
> **Mike Fave:** Some of this stuff. Well, that's the other thing. It's like this is the whole thing that's also questionable to me. I want to improve my NAD to NADH ratio. So I'm going to go on a low-carbohydrate diet and then plug HGH. So you're going to push fat oxidation and then further push fat oxidation. How is that improving your NAD plus NADH ratio from some... like an overall picture it's like it's not so you're going to slam nicotinamide riboside fine i mean if you want to like have to do it that way then this doesn't make any sense like if you actually go into the and understand what's going on in the mitochondria it's like that really doesn't make that much sense at all

### Source 8 — #43 - All things hormones, metabolism and health with Dr Ray Peat & Emma Sgourakis

Ray Peat · Interview · Apr 4, 2021

> **Ray Peat:** It helped them make their own glucose and return to health and a normal diet. In just a matter of a few weeks, the myth that glucose or that sugar causes diabetes was sustained and became part of the background of the insulin treatment and then of the metformin. I think fenformin was the... preceding a very toxic glucose waster.

### Source 9 — Baking soda may treat cancer, metformin may cause it

Georgi Dinkov · Article · May 31, 2019 · https://haidut.me/?p=171

> The reason I mention the 20g dosage is that it also happens to be the most widely used dosing regimen for enhancing performance among athletes. The performance-enhancing effect is achieved through the same mechanism with which baking soda is therapeutic for cancer – i.e. neutralizing lactic acid (lactic acid promotes muscle fatigue), and increasing CO2 (which improves tissue oxygenation and further depresses lactic acid synthesis).
>
> There you have it folks. After decades of absolute incompetence (and possibly fraud as well), the truth is slowly coming out. Soon, it may very well turn out that your grandmother’s remedies (notable members of which include aspirin and baking soda) pack more punch than the latest “advances” in medicine, even against something as serious as cancer!
>
> [references]

### Source 10 — Top diabetes drug Metformin causes muscle atrophy by activating AMPK/myostatin

Georgi Dinkov · Article · Dec 7, 2024 · https://haidut.me/?p=2724

> The drug metformin probably needs no introduction here. It is one of the oldest and most widely used drugs for diabetes II worldwide. It is often a so-called first line of therapy for many/most diabetes patients and its mechanism of actions and side effects are fairly well-known. As one of the study quotes below states, up 90% of diabetes II patients are taking metformin. While medicine prefers to ignore/downplay the serious side effects of metformin – lactic acidosis due to metformin being an inhibitor of Complex I of the electron transport chain (ETC) – the “beneficial” effects of metformin are touted non-stop and the general consensus is that metformin works mostly by activating the enzyme AMPK. That enzyme also happens to be activated by “endurance” exercise, fasting / caloric restriction (CR), and/or low-carb diets. The pro-AMPK effects of metformin are the main reason the drug is being promoted as an exercise- or CR-mimetic, which is why metformin is currently a very hot topic in anti-aging and obesity research. It is worth noting that one of the main effects of AMPK activation is increased fatty acid oxidation (FAO), which is another reason metformin is being promoted for diabetes II – i.e. the idea is that burning a lot of fat will lead to leanness and thus reversal of diabetes. Yet, if one looks at metformin from the bioenergetic point of view the drug looks like pure poison. Aside from being able to kill a person through lactic acidosis (30%+ lethal even with emergency medical treatment), massively increasing FAO hardly sounds like something a person would want to induce on a regular basis. Unsurprisingly, several studies have come out in recent years demonstrating that metformin promotes cancer growth by increasing lactate and FAO, while anti-lactate measures such as baking soda are therapeutic. Since AMPK is what drives most of these negative effects of metformin, one would expect that inhibiting AMPK would be therapeutic. Well, see the study below:-)
>
> [references]
>
> In further corroboration, using metformin in diabetic patients does not improve the course of the disease. It does lower blood sugar, but that was recently discovered to be due to its inhibitory effects on gluconeogenesis and not due to AMPK activation or increased FAO.

_Generated 2026-07-20 from the Bioenergetic Oracle corpus._