Biomarkers

A deficiency in active B12 can result in fatigue, muscle weakness, reduced endurance, poor coordination, and even brain fog. These symptoms are often misattributed to overtraining.

Albumin can provide insight into your nutritional status, inflammation, hydration, and overall recovery - all key factors for athletic performance.

Cortisol is your body’s primary stress hormone and is essential for managing energy, inflammation, and recovery.

Creatine kinase (CK) is an enzyme released into the blood when muscle tissue is damaged. It’s a key marker for muscle stress and recovery, helping athletes understand how their body is responding to training loads.

Creatinine is a waste product formed when creatine, a key compound in muscle energy metabolism, breaks down. Creatinine levels offer insight not just into kidney health but also hydration status, muscle mass, and recovery.

eGFR (estimated glomerular filtration rate) measures how well your kidneys are filtering waste from your blood. eGFR helps flag early signs of kidney stress. It's particularly important when monitoring hydration, recovery, or the impact of prolonged endurance training.

Ferritin is a blood protein that transports iron, making it a vital marker of your body’s iron reserves. For athletes, especially endurance and female athletes, the overall iron status, reflected by ferritin, is closely tied to red cell production which impacts oxygen delivery, energy, and performance capacity.

Follicle-stimulating hormone (FSH) is a reproductive hormone that regulates the development of eggs in women and sperm in men. For athletes, especially those experiencing menstrual changes, low testosterone, or symptoms of hormonal imbalance, FSH is a critical marker.

Testosterone is a key anabolic hormone that supports muscle growth, strength, energy, and recovery. “Free testosterone” refers to the active form circulating in your blood, which is available to tissues and responsible for its performance-enhancing effects.

Haemoglobin is the protein in red blood cells responsible for carrying oxygen from your lungs to your muscles. For athletes, it's one of the most important markers of aerobic capacity, endurance, and recovery.

hs-CRP is a marker of inflammation in the body. While some inflammation is a normal part of the training and recovery cycle, persistently elevated levels may indicate systemic stress, poor recovery, or even underlying illness.

LH is a powerful indicator of how well the body is coping with training demands, nutrition, and stress.

Oestradiol is the primary form of oestrogen in premenopausal women and plays a vital role in regulating the menstrual cycle, bone health, and metabolism. For female athletes, it’s a key indicator of hormonal balance and long-term performance health.

For female athletes, progesterone is a marker of hormonal resilience, energy balance, and recovery. Persistently low levels can indicate disrupted cycles, under-fuelling, or the early signs of RED-S.

Prolactin can reveal hidden hormonal imbalances, particularly in athletes experiencing fatigue, low libido, or cycle irregularities.

Red blood cells (RBCs) carry oxygen from your lungs to your muscles and carbon dioxide away from your tissues back to the lungs. A higher RBC count typically means better oxygen delivery, enhancing endurance, stamina, and recovery.

Sex Hormone Binding Globulin (SHBG) is a protein made by the liver that binds to sex hormones, primarily testosterone and oestrogen, in the bloodstream. It controls how much of these hormones are “free” and biologically active.

TSH controls thyroid hormone production, regulating metabolism, energy, and temperature balance. Abnormal TSH levels can signal underactive or overactive thyroid function, both of which can impact endurance, recovery, and weight management.

Free T4 is the inactive precursor to T3 (the active thyroid hormone). Together, they support energy output, recovery, and endurance.

Total testosterone reflects the overall level of testosterone in the bloodstream, both bound and free. It’s a primary driver of muscle growth, strength, libido, energy, and recovery in both men and women.

Athletes with disrupted T3 levels may struggle with recovery, fatigue, and poor adaptation to training.

Urea is a waste product formed from the breakdown of protein. It’s filtered by the kidneys and is a useful indicator of hydration, training load, and protein metabolism in athletes.

Vitamin D is a fat-soluble vitamin that plays a crucial role in immune health, muscle function, inflammation control, and bone strength.

WBC count can reveal how well the immune system is coping with training, travel, or illness.