Drug facts

Semaglutide and bone density

By David Chen·Editor·Reviewed September 2026

What the label records¹

Section 6.1 of the Wegovy label carries a subsection headed Fractures, which reads in full:

In the CV outcomes trial in adults, more fractures of the hip and pelvis were reported on WEGOVY® than on placebo in female patients: 1% (24/2,448) vs. 0.2% (5/2,424), and in patients ages 75 years and older: 2.4% (17/703) vs. 0.6% (4/663), respectively.

In a clinical trial in adults with MASH, fractures occurred in 4.4% of WEGOVY®-treated patients (2.6 cases per 100 patient years) compared to 3.3% of placebo-treated patients (2 cases per 100 patient years). Fractures were reported in both males and females with a median age of 61 years (range, 44 to 75).

The trial behind those rows randomized 17,604 adults aged 45 and older with established cardiovascular disease and a body-mass index of 27 or more, none of them with diabetes, to semaglutide 2.4 mg weekly or placebo; median exposure was 37.3 months on the drug and 38.6 on placebo. It is summarized on semaglutide’s long-term safety record.

Two limits belong beside the figures. The first is the label’s own: in that trial, safety collection “was limited to serious adverse events (including death), adverse events leading to discontinuation, and adverse events of special interest” — so these are the fractures that reached one of those categories, not a count of every broken bone. The second is what is absent: figures are given for women and for adults 75 and older, and a search of the whole label finds no fracture rate for men or for younger adults anywhere in it.² Section 8.5 repeats the age finding in one sentence — “patients aged 75 years and older reported more hip and pelvis fractures in the WEGOVY® injection-treated patients than placebo-treated patients” — and that is the whole of it. The label reports the rates; it names no cause, and it carries no bone warning among its eleven warnings and precautions.

What Ozempic’s label says³

Nothing. Across the whole document, “fracture” appears zero times, and so do “osteoporosis”, “bone mineral density” and “DXA”. The four appearances of “bone” are the peptide backbone of the molecule, twice; fetal skeletal findings in animal studies; and a rat bone-marrow test for genetic toxicity. None of them is about anybody’s skeleton.

That silence is not a clean bill of health. Ozempic is the same molecule approved for type 2 diabetes at a lower maximum dose — 2 mg a week against Wegovy’s 2.4 mg maintenance dose — and its label reports the outcomes its own trials measured. No bone outcome is among them, which means the question was not answered there rather than answered reassuringly. The two documents differ in more than dose: see Ozempic against Wegovy.

The trial built around bone⁴

One randomized trial has been designed around this question rather than reporting it as a side note. In Denmark, 64 adults at increased fracture risk — 55 postmenopausal women and nine men, mean age 63, mean body-mass index 27.5, none with type 2 diabetes — were assigned to semaglutide 1.0 mg weekly or placebo for 52 weeks. Entry required a T-score below −1.0 at the hip or spine, or a low-energy fracture in the previous three years. The primary endpoint was a marker of bone formation, P1NP.

So the thing it set out to test came back negative — semaglutide did not raise bone formation — and the secondary measures moved the other way: more resorption, and less bone at the spine and hip than placebo. The authors’ own reading is that “the observed increase in bone resorption in the semaglutide group may be explained by the accompanying weight loss”, and their discussion adds the part that matters most to a reader: “It remains to be investigated if these changes in aBMD translate into changes in fracture risk.”

Size matters to how much weight this carries. Sixty-four people over one year, at 1 mg — below the 2.4 mg maintenance dose used for weight reduction — is not a trial that can count fractures, and it was not trying to.

A smaller trial in older adults⁵

A 20-week pilot trial randomized 20 adults with a mean age of 72.7, living with prediabetes or diabetes and with overweight or obesity, to semaglutide 1.0 mg plus lifestyle counseling or to lifestyle counseling alone. Weight loss was greater with the drug (−5.3% against −0.89%). Whole-body bone density did not differ significantly between the groups (p = 0.77), and neither did the two turnover markers (p = 0.56 and p = 0.78). The authors flag the direction anyway: density was consistently lower and turnover higher in the semaglutide group, without reaching significance in 20 people over 20 weeks. The comparator was counseling, not placebo, and the analysis was done after the fact.

What the record studies found⁶

Away from the trials, three studies read existing patient records, and they do not point one way.

• Semaglutide starters, matched to other drugs. In an electronic-health-record network, people with obesity who started semaglutide were matched one-to-one on 215 characteristics to people starting comparators. Among those who also had type 2 diabetes, major osteoporotic fracture over three years was less common on semaglutide than on empagliflozin (hazard ratio 0.69), glipizide (0.72) or usual care (0.84). Among those without diabetes, there was no significant difference on any comparison over two years, and osteoporosis diagnoses did not differ in most comparisons either.
• Scans before and after, semaglutide and tirzepatide together. ⁷ A single center matched 255 people taking semaglutide or tirzepatide to 255 non-users with scans over the same period. Both groups lost bone at the hip and femoral neck, by a similar amount, after a median 17 months and a median 5% weight loss; among those without diabetes, hip loss was greater in the drug group (−1% against −0.6%). Because the two molecules are pooled, this is a finding about both of them, not about semaglutide on its own.
• Oral semaglutide, with nothing to compare against. ⁸ Thirty-six adults with type 2 diabetes took oral semaglutide, climbing from 3 mg to 14 mg daily. At 52 weeks, volumetric density at the tibia had risen (317.4 to 331.6 mg HA/cm³) — a change the paper reports at p = 0.06, which is not statistically significant — and the authors read the microarchitecture as improved. With no untreated group, a single-arm result cannot separate the drug from everything else that changed in a year.

Records can show that two things travel together. They cannot show that one caused the other, and people prescribed one drug differ from people prescribed another in ways no matching fully removes.

Why weight comes into it⁴

Every study above has the same shadow over it: the weight itself. Bone responds to the load it carries, and the trial that measured bone most carefully also produced a 6.8 kg difference between its groups. Its authors offer two explanations and decline to choose — skeletal adaptation to lower mechanical loading after weight loss, a direct effect of semaglutide on bone, or both — and they say plainly why they cannot: the placebo group did not lose comparable weight. One detail in their data favors loading. Cortical thickness fell at the tibia, which bears weight, while the distal radius, which does not, did not change.

This is the same open question that sits under semaglutide and muscle loss: a scale measures how much left, never what left. The weight results themselves are on STEP 1.

What this page is not

This page reports what the labels and the studies record, and it offers no advice: whether any of it applies to you, and what to do about it, is a question for a prescriber. See the medical disclaimer, and the full table of reactions for what else the label counted.