Metformin for PCOS: Weight Loss Benefits and Beyond

Polycystic ovary syndrome (PCOS) is a complex hormonal condition affecting an estimated eight to 20 percent of women of reproductive age worldwide. 

If you have PCOS and struggle with weight management, you’re not alone. But treatments are available to help. That’s where medications come in — like metformin for PCOS.

Originally developed for type 2 diabetes, metformin is now widely used off-label for PCOS. So, could metformin be a helpful tool in managing PCOS symptoms, including weight gain?

Let’s break down how this medication works, potential metformin PCOS weight loss benefits, how it can help with other symptoms, and what you need to know if you’re considering metformin for PCOS.

PCOS is polycystic ovarian syndrome. It gets its name from the tiny, fluid-filled follicles (aka cysts) that sometimes form on the ovaries. But, fun fact: Not everyone with PCOS actually has cysts.

“PCOS is a complex metabolic condition that affects multiple body systems, making it challenging to treat,“ explains Jessica Shepherd, MD, board-certified OB/GYN and Chief Medical Officer of Hers. She notes that diagnosis typically involves some combination of lab work, ultrasounds, and physical symptoms.

Though its exact cause isn’t fully understood, experts think PCOS is linked to genetics, inflammation, and metabolic dysfunction — which basically means the body’s metabolic processes are disrupted.

The key diagnostic criteria for PCOS include:

• Hyperandrogenism. This is when you have high levels of androgens in your body. Androgens are also called male sex hormones, though women have them too (like testosterone).

• Irregular or infrequent menstrual cycles. This is often caused by anovulation (which means you don’t ovulate).

• Polycystic ovaries. This can be spotted in an ultrasound and is sometimes — but not always! — associated with pelvic and abdominal pain or intense period cramps.

Unsurprisingly, many of the symptoms used to diagnose PCOS are also the ones that impact daily life the most. Common symptoms of PCOS include:

• Irregular ovulation and infertility. PCOS is the most common cause of infertility and subfertility (a reduced ability to get pregnant). But, crucially, it doesn’t mean pregnancy is impossible. “This is one of the biggest misconceptions about PCOS,“ Dr. Shepherd notes. There can be ways to manage ovulation and improve fertility.

• Weight gain and metabolic issues like obesity or overweight. PCOS makes it easier to gain weight and harder to lose it. Research suggests 38 to 88 percent of people with PCOS have overweight or obesity. This can lead to hypertension (high blood pressure) and high cholesterol.

• Insulin resistance. This means the body doesn’t use insulin efficiently, which can lead to higher blood sugar (glucose) levels, weight changes, and energy dips. Over time, insulin resistance can raise the risk of diabetes mellitus, including type 2 diabetes and gestational diabetes.

• Hormonal imbalances. Higher androgens can lead to acne, hair loss or thinning on the scalp, and increased facial or body hair growth (called hirsutism).

PCOS can feel overwhelming, but the good news is there are treatments to help manage symptoms and improve quality of life. One of those options? Metformin.

So, what does metformin do for PCOS?

Metformin is a medication that helps improve insulin sensitivity, meaning it makes the body respond to insulin more effectively. This helps lower insulin levels overall, which can have a ripple effect — regulating menstrual cycles, supporting ovulation, and even reducing androgen levels.

By improving insulin resistance, metformin may reduce sugar cravings, help the body burn fat more efficiently, and even slightly lower appetite, all of which can make weight loss easier.

Weight loss might help improve the other symptoms of PCOS, too. It’s even associated with boosting fertility.

Research on Metformin for PCOS

Here’s what the research says about metformin for PCOS:

• In one large study on people at high risk for type 2 diabetes, researchers noticed that metformin didn’t just improve blood sugar — it also led to significant decreases in weight and waist size.

• A 2020 meta-analysis of 21 trials found that metformin had a modest effect on lowering BMI (body mass index), with the biggest impact seen in people with obesity.

• Another smaller study on metformin for weight loss found that, on average, patients lost between 13 and 15 pounds while taking it.

Dr. Shepherd also explains that metformin can help cause insulin release, which helps control the hormonal imbalances and metabolic disruptions associated with PCOS.

So, while metformin isn’t officially FDA-approved for weight loss, there’s promising evidence that it can help with weight management — especially for those with insulin resistance.

Dosages of Metformin for PCOS

Metformin dosing for PCOS varies from person to person.

A healthcare provider will determine the best dose for you based on your individual needs and how well your body tolerates and responds to the medication.

The tablets usually come in three doses:

• 500 milligrams (mg)

• 850 milligrams

• 1,000 milligrams

So, what is the lowest dose of metformin you can take for PCOS? The lowest effective dose typically starts at around 500 milligrams once daily, with gradual increases as needed.

Many people with PCOS end up taking 1,500 to 2,000 milligrams per day, split into two or three doses.

But again — this is something to work out with your medical provider based on your health needs and goals.

Side Effects of Metformin for PCOS

Like any medication, metformin comes with potential side effects, whether it’s taken for PCOS or diabetes. The most common side effects of metformin are gastrointestinal issues like:

• Diarrhea

• Nausea

• Vomiting

For most people, these side effects improve over time as their body adjusts. Taking metformin with food and starting at a low dose and then gradually increasing it over time can help minimize tummy troubles.

Avoiding certain foods could help, too. “Foods that increase acid may cause problems,“ like bloating and gas, says Craig Primack, MD, an obesity medicine physician who serves as the Senior Vice President of Weight Loss at Hims & Hers.

Foods to avoid while taking metformin for PCOS while adjusting include:

• Fried, greasy, and processed foods

• Sugary foods and drinks

• Fatty cuts of meat

• Spicy and garlicky foods

• Alcohol

If acidic healthy foods (like citrus fruits) don’t bother you, there’s no need to cut them out. On the other hand, if any food seems to cause discomfort, it’s probably best to avoid it for now — even if it’s typically considered healthy.

Less common side effects of metformin include:

• Chest discomfort

• Headaches

• Sweating

• Weakness or fatigue

• Hypoglycemia (low blood sugar) — though this is more common among those also taking other diabetes medications

One rare but serious adverse effect can be lactic acidosis, a condition where lactic acid builds up in the blood. This happens when the body isn’t getting enough oxygen to properly break down glucose, and while it’s very uncommon, it can be dangerous.

Lactic acidosis is mostly seen in patients with kidney or liver issues. Your healthcare provider will make sure you’re a good candidate for metformin before prescribing it.

Metformin is commonly used for PCOS off-label. But another diabetes medication, Ozempic® (the brand name for the active ingredient semaglutide), has also gained attention — especially for its potential effects on weight loss and metabolic health. This includes those with PCOS and obesity or overweight.

So how do these prescription drugs compare?

Metformin works by improving insulin sensitivity, lowering glucose production, and regulating menstrual cycles. It may also help support weight loss and reduce androgen levels.

Semaglutide, a GLP-1 receptor agonist, helps regulate blood sugar, slow digestion, and reduce cravings, which can lead to significant weight loss.

Research on Semaglutide for PCOS

Ozempic isn’t FDA-approved for PCOS. But one study found that GLP-1 medications (including semaglutide) improved weight loss, insulin sensitivity, and hormonal balance in women with PCOS.

Another study looked at women with obesity and PCOS who had struggled to lose weight through lifestyle changes alone. It found that weekly semaglutide injections were beneficial. The medication also seemed to help regulate 80 percent of the participants’ periods.

Interestingly, some research suggests that combining metformin and GLP-1 medications may be even more effective at improving insulin sensitivity than using either one alone.

More clinical trials are needed to fully understand. But for now, both metformin and GLP-1s like Ozempic might be a good option for those with PCOS struggling to lose weight. A healthcare provider can help determine which approach — or combination of meds — might work best for you.

Learn more in our metformin versus Ozempic drug comparison guide.

Beyond off-label metformin therapy, your healthcare provider might recommend other treatment options, depending on your symptoms and goals:

• For acne and irregular cycles. Oral contraceptives (birth control pills) or anti-androgen medications like spironolactone and flutamide can help regulate hormones and reduce acne breakouts.

• For fertility support. Options like clomiphene citrate (Clomid®), in vitro fertilization (IVF), or, in some cases, ovarian surgery may be considered if other treatments aren’t effective.

• For weight loss. Your provider might recommend making lifestyle modifications like dietary changes and increased exercise first. Other oral weight loss meds, GLP-1s, or bariatric surgery may also be an option.

• For mental health conditions. PCOS is linked to an increased risk of anxiety and depression. Therapy, medication, or a combination of both can help manage symptoms and improve overall well-being.

• For excess hair growth. If PCOS-related hair growth is bothering you, treatments like hair removal creams, laser hair removal, or electrolysis can be safe and effective options.

In addition to these medical treatments, it’s also important to prioritize lifestyle habits — such as eating nutritiously, exercising regularly, getting enough sleep, and drinking plenty of water — to set a healthy foundation for pursuing your weight loss goals.

PCOS looks different for everyone, so the best treatment plan is one tailored to the patient’s body and unique needs. Your healthcare provider can help you navigate the options and find what works best for you.

Managing PCOS can feel overwhelming, but finding the right treatment can make a real difference. Many women with PCOS experience insulin resistance and hormonal imbalances, which makes it harder to lose weight and easier to gain it. Metformin is one option that may help.

Here’s what to keep in mind when considering metformin for PCOS:

• Metformin is widely used off-label for PCOS because it improves insulin sensitivity, helps regulate blood sugar, helps balance hormones, supports regular ovulation, and, for some, even aids in weight loss.

• While not officially a weight-loss drug, metformin may make weight management easier by reducing sugar cravings and improving metabolism.

• Losing weight — if appropriate for you — can improve insulin sensitivity, reduce your risk for health conditions like cardiovascular disease, and even boost fertility.

• Metformin is one of several treatment options for polycystic ovary syndrome — lifestyle change and GLP-1s may also help manage symptoms.

If you’re interested in exploring weight loss medications like metformin or semaglutide for PCOS, take our free online assessment to connect with a licensed healthcare provider. There’s no one-size-fits-all approach, but you do have options.