Science Behind Salhy

The Salhy personal hydration test measures personal hydration levels using saliva. Salhy works by bringing together different attributes of your saliva to calculate a hydration index. It helps you understand and optimise your level of hydration.

Simply place the Salhy test point on your tongue for a few seconds. Your saliva activates different biomarker indicators that provide a multi-faceted snapshot into your hydration. The test takes 2 minutes to process, with the results of the hydration indicators captured and interpreted by the Salhy smartphone software app.

The Salhy app uses advanced machine vision to scan your test and analyse each biomarker indicator. It can be used in all environments, even when out of mobile range

The Salhy hydration test is not a medical device and is not a substitute for professional medical advice. Salhy is a tool to support your personal hydration

Science Behind Salhy

The Salhy personal hydration test measures personal hydration levels using saliva. Salhy works by bringing together different attributes of your saliva to calculate a hydration index. It helps you understand and optimise your level of hydration.

Simply place the Salhy test point on your tongue for a few seconds. Your saliva activates different biomarker indicators that gauge your hydration level. The test takes 2 minutes to process, with the results of the hydration indicators captured and interpreted by the Salhy smartphone software app.

The Salhy app uses advanced machine vision to scan your test and analyse the results. It can be used in all environments, even when out of mobile range

Using Saliva to Understand Personal Hydration

Saliva is a practical and non-invasive fluid for monitoring hydration-related changes.
It is simple to collect and has been shown to change in response to shifts in the
body’s water balance.

The Salhy test uses multiple saliva biomarkers, enabling a broader view of hydration-related change.

How these Biomarkers work together

Salhy evaluates these biomarkers simultaneously, providing rapid insights into hydration status trends. This supports individuals and teams in developing informed hydration strategies in workplace and performance environments.

Saliva biomarkers that may reflect changes in hydration level:

Ionic (Electrolyte) Concentration

As salivary water content decreases during dehydration, overall saliva osmolality increases. Electrolytes become more concentrated, including ions such as sodium and chloride.

Saliva Viscosity

Dehydration reduces saliva flow and water (serous) components, making saliva thicker. Increased viscosity is commonly observed as hydration status declines, while well-hydrated individuals typically have thinner, more fluid saliva.

Urea Concentration

Urea concentration may increase during dehydration as the body conserves water. Prolonged physical activity or heat exposure can also influence urea levels, reflecting hydration-related physiological strain.

Protein Concentration

Reduced salivary water during dehydration leads to relative concentration of proteins. Additionally, certain proteins may increase in response to sympathetic nervous system activation or physiological stress associated with intense activity or heat exposure.

How does Salhy calibrate for variability in Saliva?

Human saliva is inherently variable, both between individuals and within an individual, according to things such as time of day, whether you just eaten or even if you are taking medication.

The Salhy bio markers and software work in combination to reduce the impact of personal variability on your hydration results. Our test and software include:

Step-by-step guide

Our step-by-step app instructions not only time your test they also provide important reminders on how to use the test accurately. This helps avoid accidental usage errors.

Calibration Biomarkers

The Salhy test includes a biomarker to calibrate for changes in salivary pH that could otherwise affect accuracy of the test result

Contextual data

The app tracks the time of day to adjust for natural body rhythms. Your profile info – like age group and sex – helps fine-tune your results for more accurate readings

Baseline testing

We encourage everyone who uses our hydration test to incorporate baseline testing. These are tests performed when you are optimally hydrated (click here to find out more). The Salhy app uses your baseline tests to create a personalised profile - providing more insight into your hydration
changes over time.