What is S-Testosterone?
Last updated: 30 June 2026
Reviewed by: Elfcare quality team
Testosterone is often thought of as the primary male sex hormone, but it plays an essential role in both men and women. It supports muscle mass, bone density, and physical drive, making it a key marker for assessing overall metabolic and physical vitality.
The role of testosterone in the body
In the body, testosterone promotes growth and repair. In men, it is produced mainly in the testes and is responsible for deep voice, hair growth, and sperm production. In women, it is produced in the ovaries and adrenal glands, where it contributes to libido and muscle maintenance. In both sexes, testosterone also supports cognitive clarity and confidence, and helps regulate fat metabolism. This makes testosterone relevant to body composition as well as reproductive health.
Why test testosterone?
Testosterone levels naturally begin to decline after age 30, and often brings subtle changes in energy, mood, and physical performance. Testing it helps you work out whether symptoms like persistent fatigue, difficulty building muscle, or low motivation are linked to a hormonal shift or to other lifestyle factors.
You should be extra attentive to this marker if you:
Notice a decrease in strength, muscle tone, or motivation during training.
Experience changes in libido or sexual function.
Are managing body composition and find it increasingly difficult to lose visceral fat.
Want to optimize your hormonal health as part of a longevity or performance strategy.
High testosterone: what does it mean?
A high result means your body has an abundance of this anabolic signal.
Elevated levels may indicate:
Natural vitality: In young men, high-normal levels are a sign of robust reproductive and metabolic health.
PCOS (polycystic ovary syndrome): In women, elevated testosterone is a hallmark sign that can cause irregular cycles and physical symptoms like acne or hair thinning.
Supplementation or medication: Use of TRT (Testosterone Replacement Therapy) or performance-enhancing substances will directly raise these levels.
Adrenal activity: Since the adrenals produce precursors, overactive adrenal glands can sometimes push testosterone levels higher.
Low testosterone: what does it mean?
A low result, often referred to as Low T or hypogonadism, suggests that the body's production pathways are under-functioning or under strain.
Common reasons for low levels include:
Chronic stress and high cortisol: When cortisol remains elevated over long periods, the body tends to deprioritize testosterone production in favor of managing the perceived threat.
Poor sleep quality: Testosterone production rises and peaks during the night's sleep cycles, particularly during REM sleep. Chronic sleep deprivation or fragmented sleep is one of the most direct and underrated causes of low testosterone.
Nutritional deficiencies: Lack of healthy fats, Zinc, or Vitamin D can deprive the body of the building blocks and signals needed for production.
High body fat: Excess fat tissue contains an enzyme called aromatase, which converts testosterone into estrogen, effectively lowering the amount of active testosterone in circulation.
Practical steps for testosterone optimization
You can support healthy testosterone levels by creating conditions that favour growth and repair.
Prioritize heavy resistance training: Compound movements like squats, deadlifts, and presses send a strong signal to the body to maintain and increase testosterone.
Optimize vitamin D and zinc: These nutrients are essential for testosterone production. Adequate sun exposure or high-quality supplementation can help maintain healthy levels.
Manage body fat: Reducing excess weight, particularly around the midsection, lowers the conversion of testosterone into estrogen.
Get 7–9 hours of sleep: Since your peak production happens while you sleep, missing out on rest is the fastest way to crash your levels.
Eat healthy cholesterol: Testosterone is made from cholesterol. Include whole eggs, avocados, and olive oil in your daily nutrition.
Disclaimer: These results should always be discussed with a healthcare professional. This guide is for informational purposes and is not medical advice.
Testing with Elfcare
S-Testosterone is included in Elfcare’s blood test package and in our full body health check. We analyse your total testosterone alongside SHBG and albumin to calculate your free testosterone, the portion of the hormone that is actually available for your cells to use.
Understanding your testosterone levels is a key step in proactive health. Elfcare’s tests provide the data you need to act before imbalances affect your daily life.
Summary
Testosterone is a key driver of muscle, bone, and cognitive health in both men and women.
High levels in women can signal PCOS, while low levels in men often are linked to chronic stress, poor sleep, or nutritional deficiencies.
Sleep, resistance training, and healthy fats are among the most effective levers for natural optimisation.
Mastering your testosterone data allows you to make more informed decisions about training, recovery, and lifestyle. All to help you maintain the strength and drive needed for a long, active life.
Last updated: 30 June 2026
Reviewed by: Elfcare quality team
