What’s New in Endocrinology in 2025?

Type 2 Diabetes

In adults with type 2 diabetes, subcutaneous semaglutide improves cardiovascular outcomes but until recently there was no data on cardiovascular outcomes with oral semaglutide.

In a 3-year trial looking at nearly 10,000 patients with type 2 diabetes and heart disease (or kidney disease), oral semaglutide reduced major adverse cardiovascular events (this includes nonfatal stroke, nonfatal heart attack and death from any cardiovascular cause) compared with placebo.[1]

Overall, these results suggest that oral and subcutaneous semaglutide have similar cardiovascular benefits, and the oral formulation is a reasonable alternative for patients with high cardiovascular risk and concurrent needle-phobia.

Gestational Diabetes

In a recent randomized trial comparing a sequential strategy of beginning one oral medication (metformin) and adding a second oral medication (glyburide) if glucose targets were not met versus a strategy of insulin alone, the oral strategy resulted in higher rates of large infants and maternal low blood sugars.[2] As a result, experts recommend insulin therapy for management of persistently high blood sugars during pregnancy.

Obesity

Traditional daily calorie restriction is effective in the treatment of obesity, but long-term adherence can be difficult. Intermittent fasting is any of various meal timing schedules that cycle between voluntary fasting and non-fasting over a given period. It has gained attention as a possible alternative dietary strategy. In a recent randomized trial of 165 patients with overweight or obesity, intermittent fasting achieved only slightly greater weight loss after 12 months compared with traditional caloric restriction.[3] Since caloric restriction was greater over the 12-month period with intermittent fasting, this suggest the benefit was due to reduced calorie consumption.

Osteoporosis

Typically, endocrinologists reserve zoledronic acid for patients with osteoporosis (bone loss) or osteopenia (the precursor to osteoporosis) with high fracture risk. Once we start treatment, we usually repeat infusions annually for several years. A recently published 10-year trial examined the clinical efficacy of giving zoledronic acid to early postmenopausal women with osteopenia at baseline only or once at baseline and then again at 5 years. [4] Both zoledronic acid regimens reduced the risk of major osteoporotic fractures compared to placebo.  Extended dosing intervals for zoledronic acid may be a reasonable treatment approach for postmenopausal women who opt for pharmacotherapy to prevent osteoporosis.

Thyroid

TSH is a pituitary hormone that rises as thyroid hormone levels decrease. The standard reference range for TSH values is 0.4-4.5 mU/L. It is very common in clinical practice to detect mildly elevated TSH levels in patients after age 50.  While we know there is an age-related increase in the upper limit of normal for TSH, there have been few studies looking to provide age-specific reference ranges.  In a recent study, the upper reference limit for TSH increased starting at age 50 years in females and 60 years in males.[5]  This study concluded that the upper limit for a 70–80-year-old should be raised to 6.2mU/L. This change could potentially significantly reduce the number of older individuals requiring thyroid medication.

[1] McGuire DK  et al. Oral Semaglutide and Cardiovascular Outcomes in High-Risk Type 2 Diabetes. N Engl J Med. 2025;392(20):2001. Epub 2025 Mar 29.

[2] Rademaker D et al. Oral Glucose-Lowering Agents vs Insulin for Gestational Diabetes: A Randomized Clinical Trial. JAMA. 2025;333(6):470. 

[3] Catenacci VA et al. The Effect of 4:3 Intermittent Fasting on Weight Loss at 12 Months : A Randomized Clinical Trial. Ann Intern Med. 2025;178(5):634. Epub 2025 Apr 1.

[4] Bolland MJ et al. Fracture Prevention with Infrequent Zoledronate in Women 50 to 60 Years of Age. N Engl J Med. 2025;392(3):239.

[5] Jansen HI, Age-Specific Reference Intervals for Thyroid-Stimulating Hormones and Free Thyroxine to Optimize Diagnosis of Thyroid Disease. Thyroid. 2024;34(11):1346. Epub 2024 Sep 30.