Seca vs. DEXA vs. InBody: Which Body Composition Test Is Best?
When it comes to body composition testing, people often ask us about the differences between Seca, DEXA, and InBody scans. While all three measure fat, muscle, and sometimes bone density, the accuracy, reliability, and usefulness of the data vary widely. At BodymetRx, we’ve chosen Seca because it gives the best balance of accuracy, safety, and repeatability for our clients.
DEXA (Dual-Energy X-ray Absorptiometry)
DEXA is considered the “gold standard” in research and clinical settings because it measures bone density, fat mass, and lean mass with high precision. However, it comes with tradeoffs:
- Requires low-level radiation exposure.
- Expensive and not as readily available.
- Not ideal for frequent or repeat testing.
While excellent for one-time assessments in a medical setting, DEXA isn’t the most practical tool for ongoing fitness and wellness tracking.
InBody Scans (Bioelectrical Impedance Analysis)
InBody devices are common in gyms and wellness centers because they’re quick and easy to use. But convenience comes at the cost of accuracy:
- Underestimates body fat: InBody scans often underestimate fat percentage by 3–8% compared to Seca and DEXA.
- Inconsistent readings: Results vary depending on hydration, recent meals, workouts, or even skin temperature.
- Not trusted clinically: While they produce numbers, the data is often too unreliable for medical or performance decision-making.
In fact, a large independent study published in the European Journal of Clinical Nutrition (2021) directly compared the InBody 770 with the Seca 514/515 and DEXA. The findings?
- Seca was nearly identical to DEXA (only –0.3% difference, not statistically significant).
- InBody consistently underestimated body fat by –3.1% (p < 0.0001), especially in normal-weight individuals.
- Unlike Seca, InBody’s accuracy was influenced by BMI and gender, making it less reliable across populations.
👉 Read the study here (European Journal of Clinical Nutrition, 2021).
Seca (Medical-Grade Bioelectrical Impedance)
Seca uses multi-frequency bioelectrical impedance with medical-grade precision, making it far more accurate than consumer-grade or gym-based BIA devices like InBody. Here’s why we use Seca at BodymetRx:
- 94% accurate to DEXA in published validation studies (but even more accurate when compared to MRI data!)
- Safe and repeatable: Suitable for teens, adults, and seniors with no health risks.
- Tracks trends over time: Generates easy to read, detailed reports with AI-driven health insights that help you see progress beyond just the scale.
- Practical for real life: Fast, non-invasive, and cost-effective enough for regular use.
And while some compare everything to DEXA, it’s worth noting: whole-body MRI is even more accurate than DEXA for measuring muscle — yet, in side-by-side studies, Seca has been shown to track remarkably better than DEXA without the cost, radiation, or accessibility issues. While Seca does not measure bone density, it does provide highly accurate muscle mass measurements— and strong muscle mass is one of the best indicators of overall bone health.
The Bottom Line
- DEXA = research-level accuracy, but not ideal for ongoing monitoring. Much more costly ($150-$300 per scan)!
- InBody = convenient, but the least accurate and often misleading.
- Seca = the best of both worlds — research-backed accuracy, safety, and practical repeatability. More affordable at just $49 per scan at BodymetRx!
At BodymetRx, we trust Seca because our clients deserve data they can rely on when making decisions about their health, nutrition, and fitness. Seca scans are 100% SAFE for unlimited use.
Unnecessary radiation exposure is the main reason we choose Seca body composition scanning over Dexa scans. Centers for Disease Control says: “The amount of radiation used in Dexa scans is very low and similar to the amount of radiation used in common X-rays. Although we all are exposed to ionizing radiation every day from the natural environment, added exposures can slightly increase the risk of developing cancer later in life.” No thanks! We’ll play it safe and get a Seca scan.
What you deem to be “safe” for yourself and your family is up to you! But our opinion is that if we CAN accurately measure indicators of health and fitness safely, WITHOUT THE USE OF RADIATION…why wouldn’t we!?
