S-Leptin is a blood test that measures levels of leptin, a hormone that is mainly produced by the body's fat tissue. Leptin is a central part of the body's appetite regulation, metabolism and weight balance by sending signals to the hypothalamus in the brain. When leptin levels are in balance, the hormone helps to adjust energy intake and energy expenditure, which helps prevent both overeating and starvation.
Leptin production increases in line with body fat mass. More body fat usually means higher leptin levels. However, in some individuals who suffer from obesity, the body can develop leptin resistance. This means that the brain no longer responds to leptin signals, which can result in increased hunger and difficulty regulating weight, despite high leptin levels in the blood. Leptin concentration is also affected by hormonal balance and gender, with women often having higher levels than men, which is thought to be due to the influence of estrogen.
S-Leptin Analysis
The S-Leptin blood test is used to investigate the body's energy metabolism, appetite regulation and hormonal balance. It may be particularly relevant for people who can relate to the symptoms below.
- Leptin resistance Common in obesity where the brain does not respond to leptin signals, which can lead to increased hunger and weight gain.
- Underweight and starvation Low leptin levels can be seen in malnutrition, starvation or prolonged nutritional deficiency, which can affect metabolism and hormonal balance.
- Metabolic diseases Leptin plays a role in insulin resistance, diabetes and cardiovascular disease, where high levels are often linked to chronic low-grade inflammation.
- Hormonal influence and fertility Leptin affects the hormonal system and reproductive health, where low levels can contribute to menstrual disorders (hypothalamic amenorrhea).
- Sleep and energy levels Lower concentrations have been linked to increased hunger when sleep is lacking, which can affect weight management and metabolism negative.
Recommendation for S-Leptin analysis
A leptin test may be relevant if there is suspicion of unbalanced appetite regulation, metabolic problems and/or hormonal disorders. Examples of situations where the test may be useful:
- Difficulty losing weight despite a healthy diet and exercise.
- Increased hunger and weight gain in obesity and suspected leptin resistance.
- Low energy levels, fatigue and slow metabolism.
- Hypothalamic amenorrhea, when menstruation is absent due to low energy intake.
- Suspected metabolic and inflammatory diseases, including insulin resistance and cardiovascular diseases.
- Assessment of leptin levels in extreme obesity or genetic leptin disorders.
Reference values and interpretation of test results
Leptin levels vary depending on body fat, gender and hormonal factors. High levels may indicate leptin resistance, while low levels may indicate malnutrition or hormonal imbalance. Leptin levels are generally proportional to the amount of body fat. Elevated levels are most often seen in obesity, while low levels can occur in starvation or disease states that affect fat metabolism.
- Women: Have naturally higher leptin levels than men, especially in conjunction with estrogen influence.
- Men: Normally have lower levels but may experience leptin resistance in obesity.