5 Hormones That Affect Your Ability to Lose Weight

at doctor's officeYou exercise, and you’re eating a clean diet, but you can still pinch at least an inch of fat around your hips and tummy. Why is so hard to shed that jiggly stuff? Appetite hormones play a role, but there are other hormones that regulate your metabolism and how easily you store fat. If these hormones are out of whack, it can make it almost impossible to lose weight even if you’re doing everything right. Here are five hormones that play a key role in weight control.

Thyroid Hormone

Thyroid hormone levels play a key role in regulating your metabolism. People who have an underactive thyroid usually experience weight gain and other problems such as hair loss, sensitivity to cold, poor memory, constipation, dry skin and infertility. In other words, all systems slow down. Hypothyroidism, the medical term for an underactive thyroid gland, isn’t uncommon and many people go undiagnosed. If you can’t lose weight, and you have any of these symptoms, ask your doctor to run a thyroid function study, a blood test to see if you’re producing enough thyroid hormone.


Insulin’s main function is to escort glucose into cells, but it also promotes fat storage. Many people who are overweight or obese have a condition called insulin resistance where their cells aren’t sensitive enough to the insulin they produce. This means their body has to pump out more. This contributes to fat storage, especially belly fat. Insulin resistance usually comes from being overweight, not exercising and eating a diet high in processed carbohydrates and drinking soft drinks.

Eliminating processed fats and soft drinks, and eating a diet of fiber-rich, whole food carb sources along with lean proteins and healthy fats can help insulin do its job better and help with weight loss too. It’s also important to exercise, preferably by doing high-intensity exercise, to help boost insulin sensitivity and reduce insulin’s hold on your fat stores.


Cortisol is dubbed the “stress hormone” because it’s produced when your body feels “threatened.” Physical stress from illness, inadequate sleep, eating a very low calorie diet or over-exercising can all cause cortisol levels to rise. So can emotional stress. Cortisol contributes to the breakdown of lean body tissue, and it boosts belly fat. An expanding waistline can be a sign that you’re under the spell of too much cortisol. The key here is to eliminate whatever stress is causing cortisol levels to be high.


Testosterone helps to maintain lean body mass and boost fat burning. It’s also important for healthy bones. Testosterone levels decline with age, and some experts believe this is happening earlier in life because people are exposed to estrogen-like pollutants from the environment.

Low testosterone levels can also be associated with depression and loss of libido. Doctors sometimes run a blood test to see if a person has a significant testosterone deficiency. Some men with low levels may require supplementation. As far as the sub-clinical declines that occur with aging, high-intensity exercise and resistance training can help boost declining testosterone levels.

Growth Hormone

Growth hormone is another hormone that helps to boost connective tissue growth within muscles, thereby increasing muscle definition. It also stimulates fat-burning. Like testosterone, growth hormone levels decline with age. High-intensity exercise and resistance training using heavy weights stimulates growth hormone release naturally. One more reason to make a date with a set of weights.

The Bottom Line?

These are five of the hormonal players that make it easier or more difficult to lose weight. Appetite hormones also play a role. It just goes to show how complex the body is, and why weight loss can be so difficult for some people even when they do everything right.


Ann. Intern. Med. 148 (10): 747-58.

Leave a Reply

Your email address will not be published. Required fields are marked *