For decades, diabetes treatment followed a pretty straightforward strategy: help the body make more insulin, use insulin better, or add insulin directly.

Then a new idea showed up.

Instead of focusing on insulin, researchers asked a simple question:

What if we just got rid of some of the excess sugar?

The answer became a class of medications called SGLT2 inhibitors—and they would eventually become some of the most important diabetes drugs of the modern era.

Your Kidneys Have Been Working Against You

Every day, your kidneys filter roughly 180 grams of glucose from your blood.

That sounds like a lot, but normally it isn’t a problem because your kidneys immediately grab almost all of that sugar and put it right back into your bloodstream.

They’re efficient. Maybe too efficient.

For someone with type 2 diabetes, those kidneys are essentially saying:

“Oh, you’re trying to get rid of excess sugar? Don’t worry, I found it and put it back.”

SGLT2 inhibitors block that process.

Instead of recycling glucose, the kidneys let some of it leave through urine.

The result?

Less sugar circulating in the bloodstream.

It’s a surprisingly simple idea that works completely differently from many older diabetes medications.

The Great Drug Race

Back in 2013, pharmaceutical companies were racing to bring SGLT2 inhibitors to market.

Some of the major contenders included:

  • Canagliflozin
  • Dapagliflozin
  • Empagliflozin
  • Ipragliflozin
  • Tofogliflozin
  • Luseogliflozin

Many never made it all the way through development.

Others became household names in diabetes care.

At the time this paper was published, canagliflozin had just become the first FDA-approved SGLT2 inhibitor in the United States.

Meanwhile, dapagliflozin had hit a speed bump.

Regulators wanted more safety data after concerns emerged about a possible signal involving bladder and breast cancer. Researchers couldn’t determine whether the drug caused the cancers or whether some cases already existed before treatment began.

The uncertainty was enough to delay approval.

Do These Drugs Actually Work?

Short answer: yes.

Across multiple clinical trials, SGLT2 inhibitors consistently lowered:

  • Blood glucose
  • Fasting blood sugar
  • HbA1c (a measure of average blood sugar over roughly three months)

Most patients saw HbA1c reductions ranging from about 0.5% to 1.0%.

That may sound small, but in diabetes management, that’s meaningful.

The drugs worked:

  • By themselves
  • Alongside metformin
  • Alongside insulin
  • Alongside several other diabetes medications

And unlike some older drugs, the effects tended to hold up over time.

That’s important because many diabetes treatments work well initially, then gradually lose effectiveness.

The Unexpected Bonus: Weight Loss

Here’s where things got interesting.

When excess glucose leaves through urine, calories leave too.

Researchers estimated that patients were losing roughly 200 to 300 calories per day through glucose excretion alone.

Think of it as your body accidentally throwing away a small snack every day.

Patients commonly lost between:

2 and 11 pounds (1–5 kg)

And most of that weight wasn’t muscle.

Studies suggested about two-thirds of the loss came from body fat.

Even better, some of the reduction appeared to come from visceral fat—the deeper abdominal fat associated with metabolic disease.

For a population where many diabetes medications historically caused weight gain, this was a welcome surprise.

Blood Pressure Improved Too

Another unexpected benefit emerged.

People taking SGLT2 inhibitors often experienced modest reductions in blood pressure.

Researchers saw average reductions of:

  • Roughly 2–7 mmHg systolic
  • Roughly 1–3 mmHg diastolic

That’s not enough to replace blood pressure medications, but it is enough to potentially matter.

The effect appears to stem partly from increased excretion of sodium and water through the kidneys.

In other words, these medications act a little bit like a very mild diuretic.

What’s the Catch?

Every medication comes with trade-offs.

Because SGLT2 inhibitors increase sugar in the urine, they create an environment that yeast and bacteria find attractive.

The most common side effects were:

Yeast Infections

Particularly among women.

Most cases were mild to moderate and responded to standard treatment.

Very few people stopped therapy because of them.

Urinary Tract Infections (UTIs)

UTIs occurred somewhat more often than with placebo.

Again, most cases were manageable and rarely led to discontinuation.

Dehydration Concerns

Since these drugs increase urination, researchers worried about dehydration, dizziness, and low blood pressure.

The good news?

Serious problems were uncommon and generally occurred in less than 3% of patients.

Low Blood Sugar

One of the most attractive features of SGLT2 inhibitors is that they don’t rely on insulin to work.

As a result, they generally have a lower risk of causing hypoglycemia (dangerously low blood sugar) when used alone.

The risk rises when they’re combined with insulin or medications such as sulfonylureas that already increase hypoglycemia risk.

What About the Kidneys?

At first glance, a kidney-targeting diabetes drug sounds risky.

Surprisingly, early data suggested the opposite.

Researchers observed small temporary changes in kidney function markers after starting therapy, but these generally stabilized over time.

There were even hints that the drugs might help protect kidney health by reducing pressure inside the kidney’s filtration system.

At the time, this was still largely a theory.

Today, we know that many SGLT2 inhibitors have indeed gone on to demonstrate meaningful kidney-protective benefits in large outcome trials.

Could They Help More Than Diabetes?

One of the most intriguing findings was that SGLT2 inhibitors appeared to improve several features of metabolic syndrome simultaneously.

Researchers observed:

✓ Lower blood sugar

✓ Weight loss

✓ Smaller waist circumference

✓ Lower blood pressure

✓ Reduced uric acid levels

✓ Potential improvements in certain cholesterol markers

Most diabetes medications of the era improved one problem while potentially worsening another.

For example:

  • Insulin often causes weight gain.
  • Some older medications can increase cardiovascular concerns.
  • Others negatively affect cholesterol levels.

SGLT2 inhibitors seemed different.

They appeared capable of improving several metabolic risk factors at once.

The Big Picture

When this review was published in 2013, SGLT2 inhibitors were still the new kids on the block.

Researchers knew they lowered blood sugar.

They knew patients lost weight.

They knew blood pressure improved.

What they didn’t yet know was whether these benefits would translate into fewer heart attacks, less kidney disease, and longer lives.

That question would take years to answer.

But the early evidence was promising enough that researchers ended the paper with cautious optimism.

Their conclusion was essentially this:

By convincing the kidneys to stop reclaiming every last gram of glucose, SGLT2 inhibitors introduced an entirely new way to treat diabetes—one that could potentially address multiple metabolic problems at the same time.

More than a decade later, that prediction turned out to be remarkably accurate.

Rosenwasser RF, Sultan S, Sutton D, Choksi R, Epstein BJ. SGLT-2 inhibitors and their potential in the treatment of diabetes. Diabetes Metab Syndr Obes. 2013 Nov 27;6:453-67. doi: 10.2147/DMSO.S34416. PMID: 24348059; PMCID: PMC3848644.