Smart scales and health: Are they safe for everyday use?

Smart scales and health: Are they safe for everyday use?

Article last updated September 9, 2026

Smart scales offer compelling features — with just one weight reading, they provide a deep dive into your body composition. To get this data, the scales use advanced bioelectrical impedance analysis (BIA) that sends an electric current through the body; although it's harmless, it may still worry some people. 

Some precautions are needed: because of the risk of interference, smart scales are not recommended for people with pacemakers, ICDs (implantable cardioverter-defibrillators), and other cardiac devices. It is also recommended to avoid BIA if you're pregnant; the results may not be accurate, and the effects of electric current on fetuses are still not known. 

With valuable advice on how to use these gadgets effectively and safely, you'll be well-equipped to decide whether adding a body composition measuring device can benefit your daily health routine. 


How do smart scales work?

Smart scales employ several advanced functions to provide in-depth body composition metrics, including body fat percentage, muscle mass, and bone density. Here's how they work:  

  • Bioelectrical Impedance Analysis (BIA): Smart scales send a weak electrical current through the body to measure resistance. This process estimates various metrics like body fat percentage and muscle mass by analyzing how the current travels through different tissues.  

  • Additional weight measurement components: Unlike analog scales, smart scales utilize load cell circuits and strain gauges. These components detect changes in resistance when you step on the scale and translate them into weight measurements.  

  • Data transmission: Most smart scales sync data via Wi-Fi or Bluetooth to fitness apps such as Apple Health. This feature lets users track and share information over time, providing more detailed insights into body composition changes. 

Are there any potential risks and safety concerns to using smart scales?  

BIA is essential for smart scales to provide detailed health insights; however, because of electrical currents, a small risk of interference remains. Crucially, all RENPHO body fat scales have the necessary FCC and ISED regulatory compliance marks and can claim they do not cause harmful interference. Still, some people are advised not to use any scales that utilize BIA. 

Who should be cautious? 

People with pacemakers, ICDs, and other cardiac devices 

People with artificial joints or other metal implants 

Children under 8, or people who are pregnant 

What is the potential risk? 

Interference 

Incomplete readings 

Inaccurate results 

What is the cause? 

The electric current from BIA devices can potentially cause interference with electronic cardiac devices, which may trigger device malfunctions, unwanted shocks, or paused pacing.  

Metal implants can affect body composition measurements because they conduct electricity much more easily, offering less resistance and giving the impression of more muscle and lower body fat. 

Rapid bodily changes such as fluid shifts and additional fetal tissue may not register on BIA scales, making body composition data less accurate. 

People in this category are recommended to use the scales only for weighing and to wear shoes to prevent an electric current when stepping onto the scale. Alternatively, you can use one of our digital bathroom scales, which are intended only for measuring body weight. 

It is also important to stay mindful when you’re tracking your body weight. Smart scales do a good job measuring your physical health, but they don't account for your mental health. It is important to step away if you feel overwhelmed and start developing unhealthy eating patterns from constantly tracking numbers. We recommend consulting a doctor before using smart scales if you have a history of anxious, compulsive measurement-tracking behavior. 

What are the benefits of using smart scales?

While smart scales may have a margin of error, they provide adequate, valuable insights for home use. Products like the MorphoScan Nova Body Composition Scale offer convenient access to these essential fitness metrics, helping users monitor weight management and overall health.  

  • Comprehensive health insights: They provide a deeper understanding of body composition, going beyond mere body weight measurements.  

  • Connectivity: Many smart scales are Wi-Fi-enabled, allowing seamless integration with health apps to track progress over time and enhance personal fitness journeys.  

  • Personalization: By inputting personal data such as age, gender, and height into accompanying apps, users receive more precise health analytics and personalized feedback.  

  • Integration with devices: Smart scales can sync with fitness trackers and smartwatches, centralizing health data for easier analysis. 

What are the limitations of smart scales?

Smart scales provide insights beyond just weight, including body fat percentage, muscle mass, and more through bioelectrical impedance analysis. However, they are not medical devices and can present inaccuracies.  

Limitations:  

  1. Measurement variability: The accuracy of bioelectrical impedance analysis can vary because of individual factors such as body composition and hydration levels. Consequently, the readings for body mass, bone mass, and other metrics like body water and fat percentage might differ.  

  1. Algorithm differences: Different smart scales use different algorithms, which can lead to measurement discrepancies and affect the accuracy of metrics like body composition and metabolic rate.  

  1. Model-specific effectiveness: Choosing a model with good reviews and reliable technology is crucial for getting more consistent results. The Elis 1 Smart Body Scale, for instance, is known for its user-friendliness and integration with fitness apps like Apple Health. 

5 tips for safe and effective use of smart scales

Smart scales, which use bioelectrical impedance analysis (BIA), provide a wealth of body composition metrics such as body fat percentage, muscle mass, and bone density. Here are some tips to maximize their use effectively and safely:  

  1. Regular monitoring: For accurate insights into your health trends, consistently use the smart scale over time. This helps track body mass, body weight, and water weight while keeping you motivated.  

  1. Data privacy: Consider potential privacy concerns. Smart scales collect and may share your health data with apps like Apple Health. Make sure your settings protect your privacy and give you control over data sharing.  

  1. Health conditions: Avoid smart scales if you fall into any of these categories: people with pacemakers, ICDs, or other cardiac devices; people with artificial joints or other metal implants; people who are pregnant or have osteoporosis; children under 8. The BIA feature can interfere with these conditions because it uses a small electrical current.  

  1. Health app integration: Ensure seamless syncing with fitness apps. This will enhance your ability to track, visualize, and analyze long-term changes and metabolic rate.  

  1. Product selection: Choose scales like the MorphoScan Nova Body Composition Scale, known for accurate body composition readings, which is crucial for monitoring fitness and heart health. 

Takeaway

Smart scales are safe for most people, but not everyone. Pacemakers, ICDs, and other cardiac implants carry a real risk of electrical interference, and BIA readings are not considered reliable during pregnancy. If either applies to you, use the scale for weight only, and wear shoes when you step on to avoid the current. The same caution applies to metal implants, osteoporosis, and young children, where interference or inaccurate readings are the main concern rather than a hazard.  

Everyone else can treat body-composition data as a useful trend indicator, not a diagnosis. If you have a cardiac device, are pregnant, or have another health condition, check with your doctor before you rely on any BIA reading. 

Frequently asked questions 

Are smart scales safe? 

Although smart scales are generally safe because the electric current they send through the body is very low, some precautions are still recommended.  

Children under 8 and individuals who are pregnant, have osteoporosis, a pacemaker, artificial joints, a portable ECG, or other metal implants should use the scale for weighing only and wear shoes to prevent electric current when stepping onto the scale. 

Are smart scales safe during pregnancy? 

Pregnant people are advised not to use smart scales, as the effect of electric current on fetuses is unclear. If you use one, wear shoes to prevent electric current when stepping onto the scale. 

Can I use a smart scale with a pacemaker or ICD? 

We do not recommend using a smart scale if you have a pacemaker or an ICD. Each device uses electric currents that may cause interference. If you use one, wear shoes to prevent electric current when stepping onto the scale. 

Do smart scales cause electric shock? 

Although smart scales use electrical currents for bioelectrical impedance analysis (BIA) to measure your body composition, the voltage is minimal so that you won't feel it. 

How does RENPHO body scale actually measure body fat and other metrics? 

RENPHO body scale uses a technology called Bioelectrical Impedance Analysis (BIA). 

When you step on the sensors with bare feet, the scale will send an electrical signal through your body. Because muscle tissue contains high water content, it conducts electricity easily. In contrast, fat tissue has lower water content and creates more resistance. 

By measuring this resistance, our advanced algorithm can calculate your body composition metrics, including body fat percentage, muscle mass, and water weight, with high precision. 

What are electrodes? What is the difference between a 4-electrode and 8-electrode scale? 

Electrodes are the metal plates or nodes on a scale that contact your skin and conduct electricity through your body. Each transmits signals to the others, receives signals in return, and measures the voltage difference between two contact points, which means more precise results. 

4-electrode scales typically come as a footplate with no handle, have one electrode on each corner, and send signals only through the feet. Since these scales rely on contact through the lower body, they're best for getting a general sense of what's improved and what needs to change, beyond just your weight. 

8-electrode scales typically come with a handle attached to the footplate, have four electrodes on the footplate and four on the handle, and send signals through the hands and feet. Because these scales have twice as many contact points and direct access to the upper body, they offer greater accuracy, deeper insights, and a more complete analysis. 

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