What is the Leptin test?

The Leptin blood test measures the level of leptin, a hormone produced primarily by fat (adipose) tissue. Leptin plays a central role in regulating appetite, energy expenditure, and body weight by signalling satiety to the brain.

Under normal conditions, higher body fat leads to higher leptin levels, which should reduce appetite. However, in many individuals—particularly those with obesity—this signalling becomes impaired, a condition known as leptin resistance.

Leptin testing is used in metabolic health assessment, weight management evaluation, and investigation of unexplained appetite or weight regulation issues.

Why do I need a Leptin test?

Abnormal leptin levels can indicate disrupted appetite signalling and metabolic dysfunction. Testing helps distinguish between hormonal drivers of weight gain and lifestyle factors.

You may need a Leptin test if you:

• Struggle with weight loss despite calorie control
• Experience constant hunger or poor satiety
• Have obesity or metabolic syndrome
• Have suspected leptin resistance
• Have unexplained weight gain
• Are undergoing metabolic or hormonal assessment
• Want deeper insight into appetite regulation

Conditions linked to abnormal leptin levels include:

• Leptin resistance
• Obesity
• Metabolic syndrome
• Insulin resistance
• Hypothalamic dysfunction (rare)

Benefits of the Leptin test

• Assesses appetite regulation
  Evaluates satiety signalling to the brain.
• Identifies leptin resistance
  Explains persistent hunger and weight gain.
• Supports personalised weight management
  Helps tailor dietary and lifestyle strategies.
• Complements insulin resistance testing
  Provides broader metabolic insight.
• Clinically recognised metabolic hormone
  Used in endocrinology and obesity medicine.
• Useful in unexplained weight issues
  Differentiates hormonal vs behavioural factors.
• Supports metabolic risk assessment
  Linked to cardiovascular and metabolic health.
• Simple blood test
  Requires only a single sample.

Step by step – how the test works

You can access Leptin testing UK-wide through two options:

1. Clinic appointment
   Attend your nearest UK clinic, where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist comes to your home or hotel, so you don’t need to travel.

Your sample is analysed in an accredited UK laboratory, and results are delivered securely.

Your results explained

Low leptin levels

May be seen in low body fat, starvation, or rare congenital leptin deficiency.

Typical UK interpretation:

• Below reference range for sex and BMI

Normal leptin levels

Suggest appropriate fat mass signalling and appetite regulation.

Typical UK interpretation:

• Within reference range for sex and BMI

High leptin levels

Often indicate leptin resistance, where appetite remains high despite elevated leptin.

Typical UK interpretation:

• Above reference range for sex and BMI

Leptin levels must be interpreted relative to body fat, sex and metabolic context.