Skip to main content
Drug Info

When is the best time to take metformin?

Taking this prescription with morning and evening meals can ensure consistency and minimize side effects
Joy Emeh headshot
By | May 14, 2024 Medically reviewed by Luis Bendezu, MD
empty plate next to a clock - best time to take metformin

Key takeaways

  • Metformin is a diabetes medication that is used off-label for weight management and polycystic ovary syndrome (PCOS).

  • Metformin can be taken at any time of the day, but it’s best to take it with your morning and evening meals to ensure consistency and minimize the risk of side effects.

  • If you forget a dose of metformin, skip it. Don’t take two doses of metformin at the same time.

In this article:

Metformin is an FDA-approved prescription drug for treating Type 2 diabetes. It is also sold under brand names like Glucophage, Fortamet, and Glumetza and belongs to a class of medications called biguanides. It is sometimes used off-label to prevent weight gain, manage polycystic ovary syndrome (PCOS), and treat or prevent gestational diabetes.

“Metformin has a variety of actions on the body that help the body regulate blood sugar (glucose),” says Emily Dornblaser, Pharm.D., an associate professor of pharmacy at the University of New England in Biddeford, Maine. It works to reduce high blood sugar levels by increasing the body’s response to insulin. This hormone regulates blood sugar levels by enabling the entry of glucose from the blood into the cells, where it can be used for energy. This medication is best taken with meals to help make it a part of your daily routine and reduce the chances of side effects.

When is the best time to take metformin?

“Metformin is generally prescribed to be taken with meals (e.g., breakfast and evening meal) twice daily,” says David Cutler, MD, a board-certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, California. “There is also a long-acting preparation of metformin, which can be taken once daily.” If you’re prescribed extended-release metformin once daily, it is best taken with your largest meal of the day. 

You can take metformin at any time of day. Morning and evening doses sync up with a meal, making them easier to remember and more convenient than taking medication at lunchtime, for instance. Experts recommend taking your prescription around the same time every day, so it becomes part of your daily routine.

Additionally, taking your medication with a meal, especially in the middle of the meal, instead of on an empty stomach can reduce the risk of low blood sugar (hypoglycemia) and the incidence of gastrointestinal side effects like nausea, bloating, and flatulence. Sleep disturbances and nightmares are rare side effects of metformin. If you experience these adverse effects, it’s best to avoid taking metformin very close to bedtime.

What if I miss a dose of metformin?

If you forget to take metformin, skip your missed dose and take the next dose at the usual time. Don’t take two doses together; continue with your regular dosage schedule.

If you often forget your medication, consider implementing strategies to help you remember. For example, set a recurring alarm on your phone or download an app that will send you reminders.\

What are the side effects of metformin?

Like most medications, metformin has some potential side effects that are more likely to occur when you first start taking the medication and tend to stop or reduce when your body gets used to the medication.
The most common side effects of metformin include:

  • Nausea
  • Diarrhea
  • Constipation
  • Indigestion and gassiness
  • General stomach discomfort
  • Headache
  • Reduced appetite
  • Change in taste sensation
  • Muscle pain
  • Flushing of skin

Some of the rare, but serious side effects of metformin may include:

When used for long periods and in higher doses, it can also cause vitamin B12 deficiency in some people. “We try to start people on a low dose and slowly adjust the dose up over a month (increasing the dose once a week or so based on how they tolerate it). This allows their body to get used to the medication and minimizes the unpleasant side effects,” says Dr. Dornblaser.

If you experience any side effects while on metformin, seek medical attention—especially if they are severe, persist, or go away and return. Depending on your symptoms, your provider may need to change your medication, prescribe a lower dose, or suggest dietary and lifestyle changes that may help. For example, they may suggest that you eat your meals at regular times of the day, avoid alcohol consumption, and drink plenty of water.

How do I get the most out of my metformin?

The following tips may help metformin work most effectively with minimal side effects:

  • Take it with meals. This can help reduce side effects, prevent missed doses, and maximize the medication’s effectiveness.
  • Eat regular meals to minimize fluctuations in blood sugar levels.
  • Consider eating smaller-sized meals, as this can reduce side effects like nausea and stomach pain and is linked with weight management.
  • Be physically active. Incorporating regular exercises into your daily or weekly routine is beneficial in diabetes management. It helps to lower HbA1c, a measure of your average blood sugar level over the last two to three months.
  • Avoid taking certain supplements, herbal remedies, or other medications with metformin. Medications like proton pump inhibitors, antimicrobials, and anticancer medications can interact with metformin and increase the risk of lactic acidosis—a rare but potentially fatal medical condition characterized by a buildup of lactic acid in the blood. Symptoms of lactic acidosis include a severe decrease in blood pressure, changes in mental state, and heart failure. Always tell your provider and pharmacist about all medications and supplements you are taking to avoid potential interactions.
  • Swallow metformin tablets whole. Do not chew, split, or crush them, as this may increase the risk of gastrointestinal disturbances or alter their absorption. If you have difficulty swallowing metformin pills, speak to a healthcare professional about alternative options, like the liquid formulation.
  • Avoid or limit alcohol, processed foods, and sugary beverages, such as baked goods, ice creams, candies, and sweetened drinks. These foods can spike your blood sugar levels, counteracting the actions of your medication.
  • Eat healthy, whole foods from various food groups, including vegetables, plant and animal proteins, healthy fats, and whole grains. A registered dietitian can help you create an appropriate meal plan to manage diabetes.

The effectiveness of metformin may reduce over time. Signs that metformin is working include:

  • Reduced HbA1c levels
  • Lower blood sugar levels after eating
  • Improved blood sugar regulation over time
  • Weight loss or weight management
  • Elimination of symptoms of hyperglycemia, such as fatigue, increased hunger and thirst, and blurred vision.

If you feel like the medication is no longer controlling your diabetes, let your healthcare team know. Your provider may increase the dose, combine it with another medication, or switch your prescription.

The bottom line: Take metformin at the same time daily

Metformin can be taken at any time of the day, but it’s best to take it with your morning and evening meals to ensure consistency and minimize the risk of side effects. If you forget a dose of metformin, skip it. Don’t take two doses of metformin at the same time. To minimize the risk of side effects, eat a healthy diet, avoid alcohol, and stay hydrated. Don’t hesitate to seek medical advice if you experience any adverse effects while taking this medication, especially if they don’t go away within a few weeks of starting your prescription.

Sources