Metformin Dosage Guide (Min and Max Doses)

For many people with diabetes, taking Metformin is an effective way to improve blood sugar levels, and potentially lose weight.

But it can get confusing when there are many different types of metformin and dosing approaches available. 

Figuring out which type of metformin to take and how much can take time and effort, and it should always be done alongside your doctor. 

This article will explain everything you need to know about metformin dosing for each type of metformin.

What are the different ways of taking metformin? 

Before diving into the different dosages, it’s important to know that there are several different ways of taking metformin. 

Most people take metformin orally in the form of a tablet. There are two kinds of oral tablets: regular and slow-release. 

Regular metformin tablets act more quickly and may be taken more often, whereas slow-release tablets may reduce the severity of side effects and may be taken less often. 

Never chew, crush, or break a metformin tablet. 

Metformin is also available in sachet form to be mixed with water, and in liquid form, for children or people who have difficulty swallowing. 

Read more: When to Take Metformin

What dose do you typically start therapy with? 

Metformin is generally a very safe drug, but when you are prescribed metformin, your doctor will probably start you out on a small dose to help avoid adverse side effects, such as diarrhea, nausea, and vomiting. 

Your doctor will determine your individualized dose based on your weight, health status, and health goals. Your recommended starting dose will be on the medication’s instructions that you will receive at the pharmacy. 

However, typically, most people will start on 500 mg of metformin twice a day or 850 mg of metformin once daily. If you’re seeing positive results without adverse side effects, your doctor will increase your dose from there. 

Read more: Stopping Metformin: When and How You Can Stop Taking Metformin

What is a typical metformin dose? 

The following are general guidelines for typical doses. Always check with your doctor and if these guidelines are less or more metformin than you’re currently taking, do NOT change your dose without consulting your doctor first. 

Oral dose, tablets 

Adults: 

• At first 500 mg twice per day taken with meals or 850 mg taken once per day with an evening meal, no more than 2550 mg per day 
• If you take metformin with a sulfonylurea, your metformin dose will be determined by your doctor 
• If you take metformin with insulin, 500 mg metformin per day, but no more than 2500 per day 

Children: 

• Children 10-16 years old: 500 mg twice per day, taken with meals, no more than 2000 mg per day 
• Children under 10:  to be determined by your doctor 

Oral dose, extended-release tablets 

Adults:

• Metformin (Fortamet): 1000 mg is typically taken once per day with the evening meal, no more than 2500 mg per day
• Metformin (Glucophage XR): 500 mg taken once daily with an evening meal, no more than 2000 mg per day 
• metformin (Glumetza): 500 mg taken once daily with an evening meal, no more than 2000 mg per day 
• Metformin with a sulfonylurea will depend on what your doctor recommends
• Metformin with insulin will require 500 mg metformin once a day, no more than 2500 per day 

Children:

• To be determined by your doctor 

Oral dose, extended-release suspension 

Adults:

• 5 mL once per day, taken with an evening meal, no more than 20 mL per day

Children:

• Children 10-16 years old: 5 mL once per day, taken with an evening meal, no more than 20 mL per day
• Children under 10: to be determined by your doctor 

Oral dose, solution/sachet 

Adults:

• 5 mL twice a day, or 8.5 mL once a day with meals, no more than 25.5 mL per day 
• Metformin with a sulfonylurea will be determined by your doctor 
• Metformin with insulin, at first 5 mL once a day, no more than 25 mL per day 

Children:

• Children 10-16 years old: 5 mL twice a day with meals, no more than 20 mL per day 
• Children under 10: to be determined by your doctor 

Metformin can also be taken as part of other combination therapies. If you take a metformin combination drug, discuss dosing options with your doctor.

How and when do you increase your metformin dose? 

First of all, never take more metformin than you’re prescribed. 

If you’re new to metformin and are on a lower dose, your doctor will most likely want you to stay on that for several weeks or a month to monitor you for any adverse symptoms, including diarrhea, nausea, or vomiting. 

If you’re tolerating the medication well, not experiencing difficult side effects, and are seeing improved blood sugar levels, your doctor may want to increase your dose. 

This is not something that you can do without your doctor’s guidance, however. 

Even if you were to try, your health insurance will only cover the amount of metformin that you’ve had prescribed to you, so if you start increasing your dose without letting your doctor know, you will quickly run out of medication. 

However, in most cases, your doctor will have no reason not to increase your dose if you’re doing well on metformin and wish to increase it. This will not happen instantaneously, though. Expect to be on your starting dose of metformin for up to a month after initiating treatment. 

What is the right dose for you?

This can only be determined by you and your doctor and will depend on your weight, blood sugar management, and reason for taking metformin. 

Higher doses may yield more weight loss, and if you’ve been prescribed metformin (off-label) to aid in losing weight, your dose may be higher to help combat insulin resistance more. 

On the other hand, if you’re body mass index (BMI) is lower, you’re younger, or you’re only on metformin for blood sugar management, you may be prescribed a smaller dose. 

What is the right dose for weight loss? 

The Food and Drug Administration (FDA) does not approve metformin as a stand-alone weight loss drug. However, many people with type 2 or prediabetes who take metformin do experience a modest amount of weight loss. 

This is due to increased insulin sensitivity, improved blood sugar levels, and suppressed appetite. Because it is not approved for weight loss, there is no recommended dose for weight loss. 

However, one study found that people who lost more than 5% of their body weight in the first year of the trial taking metformin were able to maintain their weight loss throughout years 6-15 than those who didn’t take metformin. 

Weight loss is modest, however. A large study of over 4,000 people with type 2 diabetes found that metformin was only associated with an average of 5 pounds of weight loss over a four-year period. 

Metformin is best used in conjunction with healthy eating and exercise for healthy weight loss.

What is the maximum daily dose?

The maximum daily dose of metformin is 2550 mg. If you’ve accidentally taken more than that in a single day, seek emergency medical help immediately, especially if you are on insulin. 

Overdosing on metformin can cause fatal low blood sugars and extreme nausea, vomiting, and diarrhea and can be hard to control.