Best time to take metformin: when and how to take it

The best time to take metformin depends on which type you've been prescribed. Immediate-release metformin should be taken with meals 1–2 times daily, while extended-release metformin is typically taken once daily with your evening meal.

When you take metformin with food, it often reduces gastrointestinal side effects like nausea, diarrhea, and stomach discomfort.

Understanding the difference between immediate-release and extended-release metformin will help you take your medication correctly. These two types work differently in your body and have different dosages.

Be sure to follow the directions on your prescription. The information below describes the typical metformin dosages for treating type 2 diabetes in adults. 

Immediate-release metformin and dosage

How to take it: Take immediate-release metformin once, twice, or three times daily with meals as directed.

Dosage: Your healthcare provider will typically start you on either metformin 500 mg once or twice daily or 850 mg once daily. Your dose may be increased weekly in 500 mg or 850 mg increments, up to a maximum of 2,550 mg per day. Amounts higher than 2,000 mg are usually divided into three doses per day to minimize digestive side effects.

The typical maintenance dose is 850 mg of metformin once daily or 1,000 mg of metformin twice daily. It's recommended to take metformin on a consistent schedule every day.

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Extended-release metformin and dosage

How to take it: Take extended-release metformin once daily with your evening meal. Swallow the tablet whole with a full glass of water.

Dosage: Your healthcare provider will typically start you on 500 mg once daily. Your dose may be increased weekly in 500 mg increments, up to the maximum recommended metformin dosage of 2,000 mg once daily.

Things to keep in mind when taking metformin

No matter which type of metformin you’re prescribed, these are some general instructions to follow:

1. Swallow extended-release tablets whole. Chewing, crushing, or splitting extended-release metformin tablets can increase the risk of stomach side effects, such as nausea or diarrhea. This can also impact the effectiveness and how the medication is absorbed. Always swallow the tablet whole with a full glass of water.

2. Stick to the same routine each day. This can make it easier to remember to take your dose, especially if you link it to a regular meal like breakfast or dinner.

3. Follow your prescribed dose closely. Immediate-release and extended-release metformin have different dosing schedules, and doses are often increased gradually to help your body adjust. Never change how much you take, split tablets, or adjust timing without checking with your healthcare provider.

Metformin is usually taken with the evening meal, assuming you’re taking it once a day. Whether you should take metformin in the morning or at night depends primarily on which type you're taking and the dosage schedule prescribed.

For immediate-release metformin taken twice daily, you'll likely take it both morning and evening with meals. So the question of "morning or night" doesn't really apply.

For extended-release metformin taken once daily, most healthcare providers recommend taking it with your evening meal.

That said, consistency is more important than the specific time of day when it comes to taking metformin. 

If you are more likely to remember your medication with breakfast or lunch and can maintain a consistent schedule with these meals, talk to your healthcare provider about whether a different timing might be better for you.

There’s no evidence of a best time of day to take metformin for weight loss effects, as metformin is not specifically approved for this use. While it’s indicated for type 2 diabetes, metformin can produce modest weight loss. In fact, one small study showed about 12 pounds lost over six months in people with overweight and obesity.

But the research doesn’t mention anything about the ideal time of day to take it. The key thing is to focus on being consistent with your medication. When you take it with meals around the same time(s) each day, it will help you build a sustainable routine.

Gastrointestinal side effects are common with metformin. About 30% of people experience symptoms such as diarrhea, nausea, and vomiting when taking the medication. These side effects can be uncomfortable enough for some that they stop taking metformin or take it less consistently than prescribed. (Although you should never change the way in which you take a medication without first consulting your provider.)

Taking metformin with food can help minimize these gastrointestinal side effects, making it easier to stick with your medication.

It’s also worth noting that diarrhea is more common with immediate-release metformin. If stomach issues don’t improve with time, ask your prescriber about trying the extended-release tablets instead.

If you miss a dose of metformin, take it with food as soon as you remember. But if it's almost time for your next scheduled dose, skip the missed dose entirely and continue with your regular schedule. Never take a double dose of metformin to make up for a missed one.

Why consistency matters: Missing doses can affect how well metformin controls your blood sugar. Research shows that people who skipped metformin more than once a week for nearly a year had worse blood sugar control than those who took it more consistently.

While missing an occasional dose isn't dangerous, taking metformin consistently as prescribed is important for the medication to work effectively.

Building a routine around taking metformin can help ensure you don't miss doses and get the most benefit from your medication. Here are some tips to help you be more consistent:

• Link it to meals. Take metformin with meals you eat at the same time every day, like breakfast or dinner.

• Set reminders. Use your phone alarm at meal times to remind you to take your medication.

• Use a pill organizer. Weekly organizers with compartments for different times of day make it easy to track whether you've taken your dose, especially if you take metformin multiple times daily.

• Store it where you'll see it. Keep your metformin in a visible spot where you prepare or eat meals, like next to your coffee maker or on the kitchen table.

As mentioned above, the most common side effects of metformin are gastrointestinal, and affect up to 30% of people. These include diarrhea, nausea, and vomiting.

How timing helps: Taking metformin with meals, as recommended, can significantly reduce gastrointestinal side effects. Your healthcare provider might start with a lower dose and gradually increase it to help minimize side effects.

Less common side effects include chest discomfort, headache, sweating, hypoglycemia (low blood sugar), weakness, and a runny nose.

Rare side effects

Lactic acidosis is a rare but serious side effect. It occurs in approximately 1 in 30,000 patients. It’s important to be mindful of this because the symptoms aren’t very specific and include malaise (general discomfort) and respiratory distress.

Risk factors include kidney or liver problems, older age, surgery, low oxygen levels, and alcohol use disorder. Limit alcohol consumption while taking metformin, as excessive alcohol increases the risk of lactic acidosis.

Although it’s rare, lactic acidosis can lead to serious complications or even death. Seek medical attention immediately if you experience low blood pressure or abnormally low body temperature.

Some medications and supplements can interact with metformin and raise the risk of lactic acidosis or low blood sugar. These include certain antidepressants, antibiotics, seizure medications, imaging contrast dyes, and alcohol. Share your full medication list with your healthcare provider to help reduce these risks.

Long-term considerations: Prolonged use of metformin can decrease vitamin B12 levels. Your healthcare provider should monitor you for this, especially if you have anemia or peripheral neuropathy. You may need vitamin B12 supplementation.

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The best time to take metformin depends on your formulation. Here’s what you need to keep in mind:

• When to take metformin: For immediate-release metformin, take it once or twice a day with meals (or as prescribed by your healthcare provider). For extended-release metformin, take it once daily with your evening meal.

• Always take it with food: Taking metformin with meals can significantly reduce gastrointestinal side effects like nausea, diarrhea, and stomach discomfort.

• Timing doesn't impact effectiveness: Whether you're taking metformin for type 2 diabetes or for an off-label use like prediabetes, polycystic ovary syndrome (PCOS), or weight management, the medication works the same regardless of the exact time you take it.

If you're exploring weight loss options, it's worth knowing that metformin isn't your only choice. Medications that are specifically approved for weight loss include GLP-1 options, such as Wegovy and Zepbound.

Ro connects you with licensed healthcare providers who can help you understand your options, answer your questions, and create a personalized weight loss plan that's right for you. Learn more about how Ro can support your weight loss journey.