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 practicality of the data vary depending on the method and the setting.
At BodymetRx, we’ve chosen Seca because we believe it provides the best balance of accuracy, safety, and repeatability for our clients. Here’s a closer look at how each option compares.
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.
Strengths:
- Highly validated in scientific literature.
- Provides bone density measurements in addition to body composition.
Tradeoffs:
- Requires low-level radiation exposure.
- Expensive and less widely available ($150-$300 per scan)
- Less practical for repeat or frequent testing.
DEXA is excellent for one-time assessments in medical settings or clinical research, but it may not be the most convenient option for ongoing fitness or wellness tracking, especially when considering cost and radiation exposure.
InBody Scans (Bioelectrical Impedance Analysis)
InBody devices are popular in gyms and wellness centers because they’re quick and easy to use. InBody uses bioelectrical impedance analysis (BIA) to estimate body composition by measuring the resistance of electrical currents as they pass through the body.
Strengths:
- Easy to use
- Fast and widely available
- Helpful for tracking trends over time in accessible settings
Considerations:
- Results can be influenced by hydration status, recent meals, exercise, skin temperature and other physiological factors.
- Research suggests that estimates can differ depending on BMI category.
In fact, a 2021 study published in the European Journal of Clinical Nutrition directly compared the InBody 770 with the Seca 514/515 against DEXA in over 200 adults (Lahave et al., 2021) The findings?
- Seca’s body fat percentage was nearly identical to DEXA differing by only -0.3% (not statistically significant).
- InBody underestimated body fat by about –3.1% (p < 0.0001).
- InBody’s deviations were largest among normal-weight participants, wile Seca’s measurements were less affected by BMI.
In Summary, InBody can be a useful and accessible tool, particularly for fitness tracking, but users should be aware of potential variability under real-world conditions.
👉 Read the study here (European Journal of Clinical Nutrition, 2021).
Seca (Medical-Grade multi-frequency bia)
Seca uses multi-frequency BIA with a phase-sensitive, 8-electrode measurement system, designed for clinical and research applications. This medical-grade precision makes it more accurate than consumer-grade or gym-based BIA devices. Here’s why we use Seca at BodymetRx:
- Demonstrated close agreement with DEXA in fat mass estimation.
- Validated against multi-slice MRI for muscle mass.
- Safe, repeatable, and no-invasive. (Suitable for teens, adults, and seniors)
- 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.
In a large validation study, Bosy-Westphal et al. (2017) compared Seca devices to multi-slice MRI (the gold standard for skeletal muscle mass, SMM) and DEXA. They found that Seca’s BIA equations explained 97% of the variance in total skeletal muscle mass measured by MRI, and 91-94% of the variance in limb muscle mass. The authors concluded that Seca “BIA equations based on MRI as a reference are more accurate for prediciton of SMM when compared with DXA” (Bosy-Westphal et al., 2017).
These findings reinforce that Seca is strongly grounded in validation data not only for fat mass, but also for muscle assessment, making it a robust choice for long-term health and fitness monitoring.
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 precision and bone density measurement, but less practical for repeat use.
- InBody = Accessible and convenient, though results may vary depending on conditions and population.
- Seca = Combines validated accuracy (including MRI-based validation for muscle) repeatability, and safetly – making it a strong choice for ongoing monitoring without radiation.
Why we use seca at bodymetrx
At BodymetRx, we trust Seca because it offers clinically validated results, repeatability, and safety, giving our clients confidence in their health and fitness data.
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!?
Schedule your Seca Scan today!
