DEXA Scan: Bone Density & Body Composition
The Dual-Energy X-ray Absorptiometry (DEXA) scan is the clinical gold standard for assessing two critical pillars of longevity: skeletal strength and metabolic body composition.
Key facts at a glance
Safety, utility, and relevance.
Osteoporosis Risk
Affects approx. 1 in 3 women and 1 in 5 men over age 50, often without symptoms until a fracture occurs.
High
Radiation Dose
Extremely low radiation—less than a standard chest X-ray and negligible compared to background daily exposure.
< 0.01 mSv
Visceral Fat Accuracy
DEXA provides one of the most accurate clinical measurements of dangerous visceral adipose tissue.
Gold Std
Scan Time
A quick, open-air scan where you simply lie flat on a table fully clothed.
~10 mins
Who this is for
- Women post-menopause and men over 50 (bone density screening).
- Anyone tracking muscle mass gain (hypertrophy) or fat loss accurately.
- Individuals interested in assessing "metabolic obesity" (high visceral fat despite normal weight).
What it measures
- Bone Mineral Density (BMD): Diagnoses osteopenia and osteoporosis.
- Lean Mass: Total muscle mass and symmetry (left vs. right).
- Fat Mass: Total body fat percentage and visceral adipose tissue (VAT).
Bone Health: The T-Score
Your bone density is compared to a healthy 30-year-old adult.
- T-score ≥ -1.0: Normal bone density.
- T-score -1.0 to -2.5: Osteopenia (low bone mass). Risk of fracture is increased.
- T-score ≤ -2.5: Osteoporosis. High risk of fracture. Treatment is usually recommended.
Body Composition: Beyond BMI
- Visceral Fat: The deep fat surrounding organs. High levels are linked to diabetes, heart disease, and inflammation.
- Sarcopenia Risk: Tracking Appendicular Lean Mass (ALM) helps identify age-related muscle loss early, allowing for intervention with resistance training and protein intake.
- Accuracy: Unlike bioimpedance scales (bathroom scales), DEXA is not significantly swayed by hydration levels.
What to Expect
- The scan is painless and takes about 6–10 minutes.
- You lie still on an open table while a scanner arm passes over you.
- Wear comfortable clothing without metal zippers or buttons (gym wear is ideal).
- Very low radiation dose means it is safe for repeated tracking (e.g., annually).
References
Clinical standards and research.
- ISCD Official Positions – Adult — International Society for Clinical Densitometry (2019)
- Assessment of osteoporosis at the primary health care level — WHO Scientific Group (2007)View source — Foundational WHO technical report on osteoporosis assessment
- Shuster A, et al.. The clinical importance of visceral adiposity — Br J Radiol (2012)
- Cruz-Jentoft AJ, et al.. Sarcopenia: revised European consensus on definition and diagnosis — Age Ageing (2019)
Content is educational and not medical advice. For personal recommendations, consult your clinician.