Leptin

What is leptin?

Leptin is a hormone your adipose tissue (body fat) releases to help your body maintain your weight on a long-term basis. It does this by regulating hunger and providing the sensation of satiety (feeling full).

Scientists discovered leptin in 1994, so they’re still studying it to understand all its effects. Currently, they’re researching leptin’s use in weight management, Alzheimer’s disease, reproductive health and infertility.

Hearing that leptin manages your weight may make you want to learn how to manage leptin. But this hormone is difficult to manipulate.

What is the function of leptin?

Leptin’s main function is to help your body maintain its weight. Leptin regulates the long-term balance between your body’s food intake and energy use. Leptin helps prevent hunger. It manages your energy balance so your body doesn’t trigger a hunger response when it doesn’t need energy (calories).

Leptin mainly acts on your hypothalamus (a part of your brain) to regulate hunger and energy balance. But you have leptin receptors in other areas of your body.

This hormone doesn’t affect your hunger levels and food intake from meal to meal. Instead, it acts to alter food intake and control energy usage over a long time to help maintain your weight.

Leptin has a more profound effect when you lose weight. As your body fat decreases, your leptin levels decrease. This signals your body to think that it’s starving. So, you may feel intense hunger and cravings, which can lead to overeating. This can make it difficult to continue losing weight.

Scientists are still studying leptin. They believe it also affects your:

• Metabolism
• Endocrine system
• Immune system

How are leptin levels controlled?

Your white adipose tissue (body fat) makes and releases leptin. White adipose tissue is the main type of fat in your body.

Because leptin comes from fat cells, the amount of leptin in your blood is directly related to the amount of adipose tissue in your body. In other words, the less body fat, the less leptin you have. The more body fat, the more leptin you have.

Leptin levels increase if your fat mass increases over time. They decrease if your fat mass decreases over time.

What happens when leptin levels are too high?

Having obesity results in high levels of leptin (hyperleptinemia). This can cause a lack of response to leptin, a condition known as leptin resistance.

Other conditions associated with hyperleptinemia include:

• Depression
• Food addiction
• Neurodegenerative disorders
• Nonalcoholic fatty liver disease
• Rabson-Mendenhall syndrome

What is leptin resistance?

If you have leptin resistance, your brain doesn’t respond as it normally would to leptin. Since leptin constantly stimulates your brain, you don’t get the sensation of feeling full. This causes you to eat more even though your body has enough fat stores.

The seeming lack of leptin also causes your body to enter starvation mode. To save energy, your brain decreases your energy levels and makes you use fewer calories at rest. In other words, it lowers your basal metabolic rate (BMR).

So, leptin resistance makes weight gain worse by making you feel hungry and lowering your BMR.

Scientists are currently working on developing medications that can treat leptin resistance.

Symptoms of leptin resistance

The main symptoms of leptin resistance are constantly feeling hungry (hyperphagia) and increased food intake. You have these symptoms despite having adequate or excess amounts of body fat.

But several other factors and conditions can contribute to these symptoms — not just leptin resistance. Scientists are still learning about leptin and may later discover other symptoms of leptin resistance.

What happens when you have leptin deficiency?

It’s very rare to have leptin deficiency (hypoleptinemia). The main condition associated with it is congenital leptin deficiency. It’s a genetic condition you’re born with that prevents your adipose tissue from making leptin.

Without leptin, your body thinks it has no body fat. This signals intense, uncontrolled hunger and food consumption. Because of this, congenital leptin deficiency results in class III obesity in children and delayed puberty.

It’s also associated with the following conditions:

• Dyslipidemia (an imbalance of lipids, including cholesterol and triglycerides)
• Fatty liver disease
• Frequent bacterial infections
• Hyperinsulinemia (excess insulin production)
• Hypogonadotropic hypogonadism (low sex hormone levels)

What test measures leptin levels?

A blood test can check your leptin level. Healthcare providers don’t routinely test for leptin levels. They typically only consider ordering leptin tests if:

• Your young child has class III obesity
• You have obesity and persistent hunger

What are normal leptin levels?

In general, normal ranges for leptin levels include:

• Adults assigned female at birth: 0.5 to 15.2 nanograms per milliliter (ng/mL)
• Adults assigned male at birth: 0.5 to 12.5 ng/mL

Normal value ranges for leptin levels may vary slightly among different laboratories. Be sure to look at the range of normal values listed on your laboratory report or ask your healthcare provider if you have questions about your results.

How do I raise my leptin levels?

There’s not much you can do to raise your leptin levels to decrease hunger and appetite. This is because your leptin levels are directly related to how much adipose tissue your body has.

One study found that sleep-deprived people had high levels of ghrelin (the hunger hormone) and lower levels of leptin. So, getting appropriate amounts of quality sleep may help regulate your hormones.

Scientists are also looking at the relationship between leptin and triglycerides, a type of fat also known as lipids. Some studies show that high triglycerides seem to impact the way leptin works. But these studies are controversial. While some scientists think an eating plan designed to lower triglycerides could help boost your leptin levels, other scientists disagree.

What foods are high in leptin?

Leptin is a hormone your body makes and not a nutrient (like vitamin C or protein). So, no foods contain leptin.