A ZYTO scan is a type of biofeedback assessment that measures changes in your skin’s electrical conductivity while software cycles through a library of “virtual items,” each representing a supplement, food, or other physical product. The device, called a Hand Cradle, reads your galvanic skin response (the same basic measurement used in polygraph tests) and compares each reading to a baseline. Practitioners, typically chiropractors or wellness consultants, use the resulting report to recommend supplements or dietary changes. The technology has no FDA clearance as a diagnostic tool, and in June 2023, the FDA issued a warning letter to ZYTO Technologies over its marketing claims.
How the Scan Works
You place your hand on the ZYTO Hand Cradle, a palm-sized device connected to a computer. The cradle sends a tiny electrical current through your skin and measures how easily it passes, a property called galvanic skin response, or GSR. This is the same principle behind lie detectors: your skin’s moisture and conductivity shift slightly in response to stimuli, stress, or even random physiological fluctuation.
Once the software establishes a baseline GSR reading, it begins cycling through what ZYTO calls “Virtual Items.” Each virtual item is a digital representation of a real-world product, like a specific brand of vitamin D or a probiotic supplement. Every time the software introduces a new virtual item, the cradle takes another GSR reading. The software then compares that reading to your baseline and looks for patterns it calls “coherence,” essentially tracking whether your skin response shifted up or down relative to where it started.
The Hand Cradle also contains what ZYTO describes as an internal antenna. According to FDA documentation, this antenna replaced an earlier in-house component called “the Tower,” which the company previously used for “the transmission, interpretation, and creation of virtual library items.” The idea that a digital signature of a supplement can be transmitted to your body and provoke a measurable skin response is the central claim of the technology, and it is the claim that has drawn the most skepticism from regulators and scientists.
What a Session Looks Like
A basic ZYTO scan takes roughly 5 to 10 minutes. You sit with your hand resting on the cradle while the software runs. There are no needles, no discomfort, and nothing to do except stay still. More advanced scans can take up to 45 minutes depending on how many items the software cycles through.
Pricing varies by practitioner and scan type. At a typical chiropractic office, a basic scan checking around 200 items runs about $95. A food-focused scan that tests responses to nearly 500 foods and 300 food contaminants costs a similar amount. Longer advanced scans that check a larger library generally cost $125 or more. Some practitioners offer scans as a complimentary add-on to other services to drive supplement sales.
Software Tiers and Report Types
ZYTO sells its technology to practitioners in several software tiers, each with a larger library of virtual items. The entry-level “Balance” software includes about 190 digital library items from roughly 30 product companies and generates wellness reports. The mid-tier “Select” software expands to over 3,000 items from 250-plus companies and adds advanced food sessions and custom category scans. The top-tier “Elite” software offers more than 8,000 items and lets practitioners build their own templates and custom reports.
There is also a separate product called EVOX, which ZYTO markets for “perception reframing” and “transgenerational reframing.” This module uses voice mapping rather than GSR and is positioned as an emotional wellness tool. It can be combined with the Select or Elite software tiers.
The reports generated after a scan typically rank products by how strongly your GSR shifted in response to their virtual items. Practitioners use these rankings to suggest which supplements, foods, or lifestyle products your body supposedly “prefers.” The reports can be customized, emailed, and stored in the software’s database.
The FDA Warning Letter
In June 2023, the FDA sent a formal warning letter to ZYTO Technologies, Inc. The letter addressed the company’s promotional materials and the way the Hand Cradle and its software were being marketed. The core issue: ZYTO’s claims positioned the device as something that could assess a person’s biological responses to specific substances, which would make it a medical device subject to FDA regulation. The company had not received FDA clearance or approval to market the product for such purposes.
The distinction matters. Galvanic skin response itself is a real, measurable physiological signal. It is well established in psychology research and is used in some FDA-cleared biofeedback devices. But those applications measure general arousal or stress responses. The leap ZYTO makes is different: it claims that GSR readings can reveal your body’s preferences for specific supplements, foods, or remedies based on exposure to a digital representation of those items. No peer-reviewed research supports that specific claim.
What the Science Says About GSR
Galvanic skin response is a legitimate physiological measurement. When your sympathetic nervous system activates, your sweat glands produce moisture that changes how well your skin conducts electricity. Researchers use this to study emotional arousal, attention, and stress in controlled laboratory settings.
The scientific problem with ZYTO’s application is twofold. First, GSR fluctuates constantly due to breathing, micro-movements, ambient temperature, hydration, and dozens of other factors unrelated to whatever “virtual item” the software happens to be presenting at that moment. Isolating a meaningful signal from that noise requires carefully controlled conditions that a practitioner’s office does not provide. Second, the concept that a digital signature of a supplement can be transmitted to the body and produce a specific, interpretable skin response has no established mechanism in physiology or biophysics. There are no published, peer-reviewed clinical trials demonstrating that ZYTO scans can reliably identify nutritional needs, food sensitivities, or health conditions.
Why Practitioners Use It
Despite the lack of clinical validation, ZYTO scans are widely used in chiropractic offices, naturopathic clinics, and wellness centers across the United States. Practitioners often frame the scan not as a diagnosis but as a way to help guide supplement recommendations. Because the software is linked to specific product companies (250 or more in the higher-tier packages), the scan naturally points patients toward purchasable products, which creates a built-in revenue stream for the practitioner.
For patients, the appeal is understandable. The scan is quick, painless, and produces a concrete-looking report with ranked recommendations. It feels personalized in a way that generic supplement advice does not. But the personalization is based on GSR fluctuations that have not been shown to correlate with actual nutritional needs or health status. A scan taken in the morning and repeated in the afternoon could produce different results based on nothing more than how much water you drank or how warm the room was.
What To Keep in Mind
ZYTO markets its own compliance materials stating the scan is safe for infants, children, pregnant women, and people with pacemakers. The electrical current involved is extremely small, so physical risk is not the primary concern. The concern is informational: making health or spending decisions based on results that lack scientific validation.
If a practitioner recommends a ZYTO scan, it helps to know that the technology is not FDA-cleared for diagnosing any condition or identifying any deficiency. The reports it generates reflect GSR fluctuations, not blood work, imaging, or any established clinical measurement. Any supplement recommendations that come from the scan should be evaluated on their own merits, not treated as a personalized prescription based on your body’s measured needs.