Do you ever feel like you're hitting the gym hard, eating right, and getting enough sleep, yet still hitting a wall with your energy and progress? Training load leaves a trace in your hormones, and a saliva swab is one way to read it.
What Summa measures is the active fraction, and how two of those numbers move against each other: free testosterone, free cortisol, and the T/C ratio. None of the three is a verdict on its own. Each is one input among many, read against your own baseline over time.
To understand what the ratio can and cannot tell you, we first need to look at the individual markers and why saliva suits them. Only the unbound, active hormones are small enough to pass through cellular membranes into your salivary glands, so a saliva sample reports the free fraction rather than the total.
Let's begin with free testosterone. Most of the testosterone in your body is bound to proteins such as SHBG and albumin, and in that bound state it is not active. Free testosterone — usually around 2% of the total — is the unbound, active form, and it is the fraction that appears in saliva. This is the hormone that enters your cells and promotes muscle protein synthesis. It is your body's primary anabolic (building) agent.
On the other end of the spectrum is free cortisol. Cortisol is essential for survival. It regulates metabolism, and it is part of what wakes you up in the morning. When you subject your body to intense physical or mental stress — heavy lifting, work deadlines, lack of sleep — your adrenal glands produce more cortisol. As with testosterone, only the free cortisol is biologically active and measurable in your saliva. When free cortisol stays elevated for long periods, the body sits in a more catabolic (breaking down) state, where muscle tissue is more readily broken down for quick energy.
That brings us to the T/C ratio: free testosterone measured against free cortisol. Comparing your primary anabolic hormone against your primary catabolic hormone gives you one way to read which direction things are trending — building or breaking down.
When your T/C ratio sits high relative to your own baseline, the picture is more anabolic. When the ratio drops — usually because free cortisol has risen, or free testosterone has fallen — the picture is more catabolic. A T/C ratio that stays low across repeated measurements is a signal of the physiological strain training is placing on you. It is one input among many, not a verdict on your training by itself, and it is best read alongside how you are sleeping, eating and performing.
You can't work on free testosterone in isolation; free cortisol moves at the same time. In practice that means prioritizing sleep, eating a nutrient-dense diet with adequate healthy fats, programming sufficient rest days into your workout routine, and managing mental stress through active recovery.
In conclusion, your training is easier to read when you can see both sides of the picture: the anabolic side represented by free testosterone and the catabolic side represented by free cortisol. Measuring these active hormones with periodic saliva testing gives you something concrete to read your recovery against, in your own numbers.
For research and wellness use only. Not for medical or diagnostic purposes.