Lindsey M. VanDyke, DO, FACOI, FEAA. Board certified in Internal Medicine and Endocrinology. Mansfield, Texas.
The short answer
Metformin is best known for treating type 2 diabetes, but its effects reach much further. It lowers inflammation and oxidative stress, protects the heart, supports the liver and kidneys, appears to help bone, and shifts your metabolism into a state where diet and exercise work better. It has been in use for over 60 years, it is inexpensive, and its safety record is unusually well established. It is not right for everyone, particularly where kidney function is poor.
What is metformin?
A tablet used first line for type 2 diabetes and prediabetes, prescribed for more than sixty years. The evidence behind it is deeper than for almost anything newer.
Dr. VanDyke calls it her favourite drug of all time, and her reason is the safety record: decades of data, and very few surprises left in it.
What are the benefits of metformin beyond blood sugar?
1. It lowers inflammation
Chronic inflammation sits underneath most major disease, from heart disease to autoimmune conditions. Metformin reduces oxidative stress and inflammation at cellular level.
2. It may have anti-cancer effects
It acts on the AMPK and mTOR pathways, which cancer cells frequently hijack to fuel rapid growth. Interrupting that may offer some protection against certain tumours. This is active research rather than settled fact.
3. It protects the heart
It improves lipid profiles, lowers inflammatory markers and reduces heart failure risk. The reduction in cardiovascular events is one of the main reasons to use it, not a side note.
4. It works like exercise in a pill
Metformin shifts your metabolism toward a catabolic state, meaning the body is primed to burn rather than store. It is technically weight neutral, so it will not drop weight on its own. What it does is make the effort pay off.
5. It supports healthspan, not just lifespan
Early research suggests it enhances autophagy, the process by which cells clear and recycle damaged components. The interest is in years lived well rather than years lived. This remains preliminary.
6. It helps the liver
It may reduce fatty liver, fibrosis and liver cancer risk, which matters more each year given how common fatty liver disease has become.
7. It protects the kidneys
Used appropriately, it appears to reduce kidney disease risk, which runs against the reputation it picked up decades ago.
8. It appeared to help during COVID
Retrospective studies found hospitalised patients already taking metformin were less likely to develop severe illness. Retrospective data is weaker than a trial, so treat it as a signal rather than proof.
9. It appears to benefit bone
Subtle, but pointing in the right direction for long term health.
Does metformin increase your metabolism?
Not in the sense of burning more calories at rest. It moves your metabolism toward burning rather than storing, which is why the effects of exercise and dietary change become more visible on it.
That is the useful version of exercise in a pill. It does not replace exercise. It makes exercise work harder for you.
Who should not take metformin?
You will read a great deal online about lactic acidosis. The honest position is that it is a real consideration in specific circumstances, not a general reason to avoid the drug. Metformin is not used in certain hospital situations, and it is not appropriate where kidney function is poor.
For someone otherwise healthy with normal kidney function, it is a very good drug. That decision belongs with a doctor who has seen your kidney function, not with a search result.
Berberine works much the way metformin does. It can lower A1c and improve insulin sensitivity, and it came from a plant, which is where metformin came from too. The difference is not natural versus synthetic. It is that one has decades of interaction and safety data behind it and the other does not, because supplements are never required to produce any.
Watch: Berberine vs Metformin, is this “natural” supplement really worth it?
https://www.youtube.com/watch?v=yHzlKVPr1ys&t=1s
Talking to an endocrinologist about metformin
Whether metformin suits you depends on your kidney function, what else you take, and what you are actually trying to achieve.
Dr. VanDyke is a board certified endocrinologist in Mansfield, Texas, seeing patients from across Dallas Fort Worth. New patients are seen within two weeks. Telehealth is available in seven states.
Call or text (817) 380-4880.
This article is educational and is not medical advice. Do not start, stop or change any medication without speaking to your doctor.
Frequently asked questions
1. What are the benefits of metformin?
Beyond lowering blood sugar, it reduces inflammation and oxidative stress, improves lipid profiles and lowers heart failure risk, supports liver and kidney health, appears to benefit bone, and shifts metabolism so that diet and exercise produce more.
2. Does metformin help you lose weight?
It is technically weight neutral, so it does not cause weight loss by itself. It makes the weight loss efforts you are already making more likely to work.
3. Is metformin safe long term?
It has been in use for over sixty years with an unusually well established safety record. It is not suitable for everyone, particularly where kidney function is impaired.
4. Does metformin increase your metabolism?
Not at rest. It shifts your metabolism toward burning rather than storing, which is why exercise and dietary change show up more clearly on it.
5. Can metformin help with aging?
Early research suggests it enhances autophagy, the cellular recycling process. The interest is healthspan, the years lived well, rather than lifespan. This is preliminary.
6. What is lactic acidosis and should I worry about it?
It is a real consideration in specific situations, such as poor kidney function or certain hospital settings, rather than a general reason to avoid metformin. Your doctor should check your kidney function.
7. Can I take metformin if I have kidney problems?
It depends on how impaired your kidney function is. This is exactly the case where the decision needs a doctor who has seen your bloods rather than a general rule from the internet.
8. Should I take berberine instead?
[DR VANDYKE TO ANSWER. She has covered this in a video, “Berberine vs Metformin.” We have not put words in her mouth here. Her answer should be pasted in.]
9. Do I need a specialist to take metformin?
Not necessarily. Many people are prescribed it in primary care. A specialist is worth seeing if your blood sugar is not controlled, or if you want to understand what else could be contributing.
10. Can I stop metformin if my numbers are fine?
Do not stop any medication without speaking to your doctor. Numbers being fine on treatment is usually a sign the treatment is working rather than a sign it is no longer needed.
11. Do doctors get paid by drug companies to prescribe medication?
No, and this myth stops people accepting treatment that would help them. Regulation is extensive. A physician cannot accept so much as a branded pen or notepad. Any payment connected to pharmaceutical education is recorded and publicly reportable under the Sunshine Act, so you can look up any doctor and check.
12. How soon can I see an endocrinologist about this?
New patients are seen within two weeks. Across Dallas Fort Worth, two months is the more common answer.
13. How does payment work?
If you have Medicare, the practice contracts directly with Medicare and bills them after your care. If you have private insurance, the practice contracts with you directly and gives you the paperwork to claim reimbursement from your insurer.