Leptin: What It Is, Function, Levels & Leptin Resistance

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Leptin is a hormone your body releases that helps it maintain your normal weight on a long-term basis. The level of leptin in your blood is directly related to how much body fat you have. Leptin resistance causes you to feel hungry and eat more even though your body has enough fat stores.

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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).

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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

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.

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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.

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

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.

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

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.

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.

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)

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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

In general, normal ranges for leptin levels include:

• Females: 0.5 to 15.2 nanograms per milliliter (ng/mL)
• Males: 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.

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.

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

Leptin is a relatively new discovery. So, scientists are still working to learn more about it, including how it affects obesity and weight loss. Leptin’s role in triggering your body’s starvation mode when your body fat decreases can make it difficult to lose weight. If you’re concerned with your body weight or want guidance on how to lose weight in a healthy way, talk to your healthcare provider. Also, consider seeing an endocrinologist who specializes in hormones and can offer weight management programs.

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Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

• Abend Bardagi A, Dos Santos Paschoal C, Favero GG, et al. Leptin’s Immune Action: A Review Beyond Satiety (https://pubmed.ncbi.nlm.nih.gov/36278927/). Immunol Invest. 2023;52(1):117-133. Accessed 1/29/2025.
• Dornbush S, Aeddula NR. Physiology, Leptin (https://www.ncbi.nlm.nih.gov/books/NBK537038/). 2023 Apr 10. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. Accessed 1/29/2025.
• Hormone Health Network. Endocrine-related Organs and Hormones (https://www.endocrine.org/patient-engagement/endocrine-library/hormones-and-endocrine-function/endocrine-related-organs-and-hormones%C2%A0). Last reviewed 1/24/2022. Accessed 1/29/2025.
• Society for Endocrinology. Leptin (https://www.yourhormones.info/hormones/leptin/). Last reviewed 7/2023. Accessed 1/29/2025.

Hormonal conditions can be tricky to find and complicated to treat. The experts in endocrinology at Cleveland Clinic are here to provide the best care.

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