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, whether you are in mobile reception or not. As long as you have your phone handy you can get immediate feedback on your hydration level. Click here for more detailed instructions and usage guide

Using Saliva to Measure Personal Hydration

Saliva is an excellent fluid for assessing personal hydration. It is non invasive, simple to test and it reliably mirrors changes in the body's water balance (hydration level).

The Salhy test uses multiple saliva biomarkers, this is more effective because your saliva changes based on the type of hydration (click here) and the physical context.

How these Biomarkers work together

Salhy measures these biomarkers simultaneously, providing real-time insights into hydration levels. This allows individuals to optimise fluid intake and develop individualised hydration strategies, improving performance, and well-being.

Saliva biomarkers that may reflect changes in hydration level:

Ionic (Electrolyte) Concentration

As salivary water drops during dehydration, overall saliva osmolality increases. Electrolytes increase in concentration, including important ions such as sodium and chloride.

Saliva Viscosity

Dehydration reduces saliva flow and water (serous) components, making it thicker and stickier. Saliva viscosity increases. Well-hydrated individuals have thinner, more fluid saliva.

Urea Concentration

During dehydration, urea levels can increase as the body conserves water by reducing urine output and reabsorbing fluid. In addition, the effect of intense physical activity or prolonged heat exposure can cause strain on the body. Muscle tissue may break down which can elevate urea levels.

Protein Concentration

The reduction in salivary water during dehydration also means that many proteins concentrate. In addition, some proteins increase in concentration because of sympathetic nervous system activation or metabolic changes associated with intensive physical activity or heat stress.

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 and other factors that could affect accuracy of the test result

Contextual data

Our App automatically records contextual factors such as time of day to account for any impacts of circadian rhythm. Setting up your profile captures and calibrates for personal factors that can change your saliva profile such as age group or sex.

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 accuracy in detecting changes in your hydration levels.