Measurement · not graded
DEXA Body Composition Scan
What the evidence looks at: agreement with four-compartment reference models, and same-day repeat precision.
How this letter has changedLatest: September 2026 · First graded.
The DEXA page has been published for months with no record behind it, which left its safety and medication text written by hand in the page's own HTML and invisible to every check that reads the data. The record carries no letter, by design: DEXA measures body composition and bone density and treats nothing, and the A to D scale grades treatment efficacy. It cites two measurement-accuracy studies rather than outcome trials. Cited: Schubert et al. (Clin Physiol Funct Imaging, 2019; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 30325573); Nickerson et al. (Int J Sport Nutr Exerc Metab, 2017; PMID 28787184).PMID 30325573 PMID 28787184
Every change to a letter on this site is dated and published. The full evidence log →
Diagnostic testing · Body composition
Dual-energy X-ray absorptiometry is the gold standard for measuring lean mass, fat mass, visceral fat area, and bone mineral density in a single 10-minute scan. It is the reference standard used in the clinical trials behind EBL's supplement and intervention grades. If you are tracking body composition changes from resistance training, creatine, sarcopenia Age-related loss of muscle mass and strength. protocols, or any longevity intervention, DEXA is the measurement that actually tells you what changed.
| What it measures | Lean mass (muscle), fat mass, bone mineral density, visceral fat area, appendicular skeletal muscle mass index (ASMI), fat-free mass index (FFMI), android/gynoid fat ratio. |
| Gold standard | Yes. Used as the primary endpoint The one outcome a trial names in advance as its main test. Results on other outcomes carry less weight. in clinical trials for sarcopenia, osteoporosis, and body composition interventions. |
| Radiation | Minimal. A single DEXA scan delivers roughly 1/10th of a chest X-ray. Equivalent to a few hours of natural background radiation. |
| Cost | $50 to $150 out of pocket at imaging centers and sports medicine facilities. Not typically covered by insurance for body composition (bone density may be covered with clinical indication). |
| Frequency | Baseline then annually if tracking intervention response. Every 2 years for bone density monitoring in post-menopausal women. |
| Key output for longevity | ASMI (appendicular skeletal muscle mass index): the primary marker for sarcopenia diagnosis. Visceral fat area, metabolic risk marker. Bone mineral density T-score, fracture risk assessment. |
ASMI (target above 7.0 kg/m2 men, above 5.5 kg/m2 women). Visceral fat area (target below 100 cm2). Bone mineral density T-score. Total lean mass trend year over year. Serial measurements are comparable only on the same scanner at the same facility.
The European Working Group on Sarcopenia in Older People 2 consensus paper defines sarcopenia using ASMI from DEXA as the primary diagnostic criterion. ASMI below 7.0 kg/m2 in men and 5.5 kg/m2 in women defines low muscle mass. This is the clinical threshold used in the EBL sarcopenia condition page.
DEXA bone mineral density at the lumbar spine and hip is the standard measure for diagnosing osteoporosis (T-score of -2.5 or below) and low bone mass (T-score between -1.0 and -2.5), and bone density is an accepted surrogate endpoint A lab value or measurement used in place of the outcome that matters, such as LDL cholesterol standing in for heart attacks. Moving a surrogate does not always move the outcome. in osteoporosis drug trials. A definition, not a study.
Consensus statement arguing that body-mass index alone is not enough and that waist circumference should be measured routinely as a marker of abdominal fat. It concerns waist circumference; it does not compare it with DEXA.
Contraindicated in pregnancy. The radiation dose is minimal and not a practical concern for annual scanning in non-pregnant adults. Patients with implanted metal (joint replacements, spinal hardware) may get artifact in the scan area.
Corticosteroids (prednisone, dexamethasone) cause bone density loss and increase fracture risk, and chronic steroid use is one of the recognized indications for repeat densitometry. Aromatase inhibitors used in breast cancer treatment accelerate bone loss. Certain anticonvulsants reduce bone density.
DEXA is the measurement standard behind EBL's sarcopenia condition page and the body composition endpoints The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. in the creatine, resistance training, and protein intervention evidence. BIA devices (including InBody) are validated against DEXA and offer a practical in-office alternative. For definitive baseline and annual tracking, DEXA remains the gold standard.
Educational use only · Not medical advice · Starting, stopping or changing any supplement or medication is a decision for your physician
EBL does not verify the regulatory status of any device. Many consumer wellness devices are not FDA-cleared The FDA found a device substantially equivalent to one already on the market. Clearance is not approval and does not require trials showing benefit., and FDA clearance, where it exists, applies only to specific indications. The grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Using any device for a health purpose is a decision for your physician.
Primary evidenceTwo papers, each linked to its PubMed record.
Schubert and colleagues (Clinical Physiology and Functional Imaging, 2019; PMID 30325573): laboratory body composition methods compared for reliability and validity in young adults. Nickerson and colleagues (International Journal of Sport Nutrition and Exercise Metabolism, 2017; PMID 28787184): four-compartment model body fat validated using DXA for body volume in physically active adults. Both are measurement-accuracy studies, not outcome trials.
These statements have not been evaluated by the Food and Drug Administration. Any grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
Papers authored on this record that are not linked elsewhere on the page. Every citation the record carries is reachable from the page it grades.
Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →