If you hear the word “hormones” and think about sex hormones, you aren’t alone. However, there are other hormones that can also play a role in obesity.

One of these is a hormone called leptin. Leptin helps your body know when to eat and when to stop eating. If you want to know more about this hormone and how it’s connected to obesity, keep reading.

What Is Leptin?

Leptin is a hormone that helps your body maintain a healthy weight. Most of the time, you feel hungry when leptin levels are low and full when they’re high. Leptin helps regulate your energy balance by telling your body how much energy it’s storing as fat compared to how much you’re using. This process is part of what’s known as leptin signaling.

Fat cells, also known as adipose tissue, make and release leptin. This makes sense because the hormone’s job is to tell your brain — especially a part called the hypothalamus — when you’ve stored enough fat. When leptin acts on the hypothalamus, it helps reduce hunger and increase energy use, preventing excess fat storage.

What Do We Know About Obesity and Leptin?

If you have more fat cells, you have higher levels of leptin. This happens because leptin production is linked with the amount of fat stored in the body. People living with a higher weight or obesity often have very high leptin levels, but their bodies don’t always respond to the hormone properly. This is called leptin resistance, where the effects of leptin are reduced even if the hormone is present in large amounts.

Leptin binds to specific proteins called leptin receptors, which are found not only in the hypothalamus (a part of your brain) but also in other parts of your body. This suggests that leptin action might influence other systems, such as the reproductive or immune systems.

In fact, your body might actually begin to think that it doesn’t have enough leptin. It can put you into “starvation mode,” lowering the number of calories you burn all day, even when you’re just resting. This can cause even more weight gain because you have more food intake and your body’s energy expenditure is lower.

The main sign of leptin resistance is feeling hungry even though your body is carrying plenty of fat. If you feel like you’re always hungry and the amount you’re eating is going up even when you don’t think you need more food, you might be dealing with leptin resistance.

Leptin may also play a role in some other medical conditions. It has been linked to certain heart problems because it also increases inflammation in the body, which can affect the way your heart works.

Leptin may also be connected to insulin resistance, metabolic syndrome, type 2 diabetes, high blood pressure, and more. Many of these medical conditions are also more common in people diagnosed with obesity, and leptin may be one thread connecting all of these together. However, researchers don’t currently understand the exact role of leptin in these conditions.

Why Does Leptin Deficiency Cause Obesity?

A few people diagnosed with obesity may have a genetic condition called leptin deficiency, or congenital leptin deficiency. These people don’t produce enough leptin because of genetic changes that they probably inherited from their parents. When this happens, your body thinks that it has very little or no body fat. People with this condition will feel hungry constantly and eat large amounts. This rare condition is often diagnosed in children and adolescents and can lead to severe obesity if it is not treated.

Leptin and Obesity Treatments

When researchers discovered leptin and the role it plays in maintaining body weight, there was some excitement about using it as a treatment for obesity. However, this got more confusing when researchers found that people living with obesity already had high levels of leptin and simply weren’t responding to it. Simply adding more leptin into their systems was not likely to help the problem.

Right now, researchers are working to better understand how and why leptin resistance occurs. They believe that it has something to do with changes to the way leptin is transported to the brain. Once they have a better understanding of how this works, they may be able to devise treatments that take on the problem from that angle. If they can prevent leptin resistance, they may be able to help people achieve and maintain a lower body weight.

There’s also more work to be done when it comes to understanding how leptin affects the body as a whole. There may be ways to regulate when it’s produced and how much is produced that researchers just don’t know about yet. This could potentially give healthcare providers tools to either lower the amount of leptin that gets produced or manage leptin resistance.

In the meantime, though there’s not a lot you can do to change your leptin levels, changing your diet may help. Certain diets, like the Mediterranean diet, seem to help people lower the amount of leptin in their bodies. They may also help fight leptin resistance.

Can You Take Leptin To Lose Weight?

If you’re diagnosed with genetic leptin deficiency, then you might be able to take leptin to lose weight and maintain a healthy weight. In this situation, taking leptin may also help lower your risk of the other related conditions that were mentioned above. Otherwise, if you’re diagnosed with obesity and do not have this genetic complication, simply taking leptin is unlikely to help with weight loss. It’s likely that you have plenty of leptin and your body is leptin resistant.

Talk to Your Doctor

You can talk to your obesity specialist if you want to know more about how it might be affecting your body and your body mass index (BMI). They can help you decide if it’s worthwhile to have your leptin levels tested. This is done via a simple blood test, though it’s not one that doctors usually order unless they have a reason to. If your levels are outside the normal range, it can give your doctor information they need to help you.

Your medical team may send you to an endocrinology specialist. These doctors specialize in the endocrine, or hormone, systems of the body. They can help you find the answers you need about leptin.

Your doctor can also help you decide if changing your diet to try to control leptin might help you achieve a healthy weight. They can talk to you about what you eat now, then help you figure out the best new diet plan for you. If you need additional help, they can send you to a registered dietitian who can dive into the details with you to help you enjoy your new eating plan.

Talk With Others Who Understand

MyObesityTeam is the social network for people with obesity and their loved ones. On MyObesityTeam, members come together to ask questions, give advice, and share their stories with others who understand life with obesity.

Have you investigated connections between leptin and obesity? Has that been helpful for you on your journey? Share your experience in the comments below, or start a conversation by posting on your Activities page.