This Hormone Might Be the Reason You Can’t Lose Weight

In most cases, the inability to lose excess weight stems from high caloric intake. Although many people try to blame this issue on hormonal imbalance and metabolic problems, it is usually just an excuse. However, there are some cases in which hormones play an important role in weight management, and people with abnormal levels of these hormones can get too obese or too skinny, even if they eat normally.

Hormonal imbalances which can cause obesity include hypothyroidism (the lack of thyroid hormones), hypercorticism (increased level of cortisol) and many others, but the hormone which has attracted a huge attention of scientists during the past few decades is called Leptin.

Leptin is produced by fat cells and released into the bloodstream. Initially, scientists thought that increased levels of leptin act on certain areas of the brain, thus suppressing hunger and food intake. That is partially true, but it is not the whole story. It has been noticed that obese persons have high leptin levels, and they still get hungry and have a high caloric intake.

Lack of Leptin Leads to weight Gain

Fasting, even for a short period of 12 hours, inhibits the secretion of Leptin from the fat cells, which induces hunger and increased food intake. Besides that, low leptin levels seem to have an effect on other hormones responsible for human metabolism, such as thyroid hormones. The overall consequences of a sudden drop of leptin levels include overfeeding, slowed-down metabolism, and ultimately weight gain. Additionally, scientists have proven that lack of leptin produces problems within the immune system, and even within the reproductive system.

Leptin Substitution Therapy

Based on the above statements, it would be logical to investigate whether leptin supplementation can help obese persons to lose weight. That topic has started to attract more and more attention of scientists from all over the world. Many experimental studies have been performed, mostly on laboratory animals. In most cases, the results of these studies have proven the assumptions of the scientists. Artificial leptin supplementation succeeded to reduce hunger and to stimulate the sympathetic nervous system, which lead to the normalization of metabolic rate. Thyroid hormone levels were also normalized and further weight gain was prevented.

However, in order to use leptin substitution therapy in humans, more research is needed, due to safety issues and conflicting opinions of researchers who are investigating the potential of this substance.

How Hormones affect Weight Loss

As we said already, thyroid hormones are important for all metabolic processes in the human body, so some people attempt to lose weight by taking thyroid hormones artificially. Although it might produce that effect, it can also lead to many serious, and even life-threatening side effects. The most common side effects of thyroid hormone supplementation are excess sweating, nervousness, heart palpitations, anxiety, and even paranoid behavior.

There is a common misconception among some people that anabolic steroids, which are analogues of testosterone, can help them lose weight. This opinion probably stems from the ripped muscles they usually see in people who use these supplements. But the truth is a little bit different. Anabolic steroids stimulate synthesis of all big organic molecules, including proteins, complex sugars, and fat. So if you are overweight or obese, anabolic steroids will help you gain muscles, but they will not help you lose fat. In fact, you might even get some extra fat while using them if you do not make an effort to spend some calories through exercise.


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Kicman AT. Pharmacology of anabolic steroids. British Journal of Pharmacology. 2008;154(3):502-521. doi:10.1038/bjp.2008.165.

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