The more I dive into GLP-1 research and open science studies, the more genuinely excited I get about how many new possibilities are emerging from recent research. It's clear that losing weight brings real health benefits, but what's really interesting is how the evidence keeps growing, showing improvements in a lot of other areas too.

In this post, I've outlined the major ones.

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“As more data comes in, I become more convinced that we may look back on these drugs as the greatest medical breakthrough of the 21st century.” - F. Perry Wilson, MD, MSCE (Yale nephrologist, researcher)

“GLP‑1‑based obesity medications may prevent, mitigate, or treat over 200 obesity‑related complications." - Ania Jastreboff, MD, PhD (Yale Obesity Research Center)

“GLP‑1 medications like semaglutide and tirzepatide could represent a "“penicillin moment” for medicine." - Robert Kushner, MD (Professor Emeritus at Northwestern University)

I haven't included inline links to the studies this time — simply because there are too many to reference cleanly, but the full list is available at the end of the article.

The SELECT trial enrolled 17,604 adults with obesity and established cardiovascular disease and the results were genuinely landmark. Participants taking semaglutide 2.4 mg weekly experienced 20% fewer major adverse cardiovascular events, meaning heart attacks, strokes, and cardiovascular deaths, compared to those on placebo.

The separation between the semaglutide and placebo event curves began to emerge within the first 6 months of treatment, far faster than weight loss alone could explain. That early divergence strongly suggests some of the protection is coming from mechanisms beyond fat loss, perhaps reduced inflammation, improved blood vessel function, or direct effects on cardiac tissue.

Heart failure with preserved ejection fraction (HFpEF) is notoriously difficult to treat. This disease makes ordinary activities exhausting. Climbing stairs, carrying groceries, walking to the car can all trigger breathlessness.

In the STEP-HFpEF trial, patients with obesity-related HFpEF reported meaningful improvements in how they felt and how far they could walk within 3 to 6 months.

Participants taking GLP-1s saw meaningful improvements across every major measure of heart failure symptom burden: quality-of-life scores improved by roughly 16 points over placebo, six-minute walk distance increased, and patients reported noticing real differences in how they felt by 24 to 52 weeks.

Modest, but consistent. In both randomized controlled trials and real world cohort studies, mean arterial pressure begins declining within the first 3 months alongside early weight loss, continues improving through 6 to 12 months, then plateaus. The effect is not dramatic on its own, but in the context of sustained cardiovascular risk reduction it adds up.

The FLOW trial, published in 2024, changed how nephrologists think about this drug class. In people with type 2 diabetes and chronic kidney disease, semaglutide significantly slowed the progression of kidney disease and reduced combined kidney and cardiovascular events. Separately, a 2024 study found meaningful albuminuria reduction in people with overweight and non-diabetic Chronic Kidney Disease at just 24 weeks. Albuminuria is one of the most sensitive early markers of kidney injury.

Metabolic dysfunction-associated steatohepatitis (MASH) is a form of liver disease where fat accumulation comes with active inflammation and scarring of liver tissue. It affects a significant proportion of people living with obesity and can silently progress toward cirrhosis over years. There are very few approved treatments, which makes the Phase 3 trial data for semaglutide in MASH genuinely exciting.

At 72 weeks, 62% of participants on semaglutide achieved resolution of steatohepatitis without worsening of fibrosis, compared to 34% on placebo. Liver enzymes ALT and AST also improved consistently across studies, tracking with reductions in liver fat content.

The glycemic effects of GLP-1 peptides are among its most well-established properties, since it was developed as a diabetes medication before it became widely used for weight management.

The SELECT trial tracked glycemic status over 3 years in people without diabetes at baseline. By week 156, 70% of patients were normoglycemic versus only 36% on placebo. More strikingly, just 1.5% of the GLP-1 group progressed to diabetes, compared to 6.9% on placebo. HbA1c reached its lowest point around week 20.

Chronic inflammation is increasingly understood to be a central driver of cardiovascular disease, metabolic dysfunction, certain cancers, and accelerated aging. Obesity is a significant contributor to that background inflammatory state.

Across the STEP 1, 2, and 3 trials, GLP-1 consistently reduced high-sensitivity C-reactive protein, a key marker of systemic inflammation. Reductions tracked tightly with the time course of weight loss and were clearly present at the end-of-treatment assessment at week 68.

In a landmark NEJM trial, semaglutide improved pain scores and physical function in people with obesity and knee osteoarthritis, with primary endpoints assessed at week 68. Earlier research established that each 1 pound lost reduces knee joint load by roughly 4 pounds per step.

But a 2025 study found evidence of cartilage stabilization and possible new cartilage growth at just 24 weeks, suggesting benefits that cannot be fully explained by mechanical unloading alone.

The connection between obesity and obstructive sleep apnea is well established. Excess weight around the neck and upper airway increases collapse risk during sleep, and weight loss reliably reduces severity.

A 2024 meta-analysis of tirzepatide for obstructive sleep apnea found significant reductions in the apnea-hypopnea index, the measure of how many times per hour breathing is disrupted during sleep. Improvements tracked with the magnitude of weight loss achieved, consistent with the idea that the primary mechanism here is mechanical: less upper airway tissue mass equals a more patent airway during sleep.

GLP-1 receptors are present in the limbic system and other brain regions involved in motivation, reward, and impulse control. Animal studies showed reductions in alcohol and drug-seeking behavior years before human trials got underway, and the first randomized human data arrived with a 2024 JAMA Psychiatry study on alcohol use disorder.

In that 9-week randomized trial, adults with alcohol use disorder who received semaglutide showed significant reductions in both alcohol intake and craving compared to placebo. This is a short study and it would be premature to position semaglutide as a proven addiction treatment, but it is a meaningful proof of concept in humans that validates what the animal data and a wave of patient self-reports have been suggesting. Many people on GLP-1 report quieter food noise, reduced interest in alcohol, and less compulsive engagement with other rewarding behaviors.

None of these outcomes happened quickly. They emerged because people stayed on treatment long enough for the biology to do its work. Heart protection in SELECT kept growing for nearly 40 months. Cartilage signals appeared around 24 weeks. The metabolic shift that moved patients away from diabetes unfolded over three years. The lesson is simple: time on treatment is part of the treatment.

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