Do Trans fats Reduce Testosterone Levels?

Fats play an important role in the human body. They are a source of energy, serve as a carrier of fat-soluble vitamins, and supply fatty acids that are essential for building and maintenance of cell membranes. Fats are also involved in the synthesis of hormones including testosterone.

And while fat is necessary for optimal health, similar to other macronutrients, they should be consumed in moderation. However, all fats are not equal and some types harm your health, including decreasing your testosterone levels. For this reason, you should choose the fats you eat carefully.

While there are many specific fats and oils, they can be classified into three main types, saturated, unsaturated and trans fats.

Saturated fats

Saturated fat usually comes from animal products like meat, and is normally solid at room temperature. The United States Food and Drugs Administration (FDA) and other similar organizations recommend that not more than 10 percent of your total daily calorie intake should come from saturated fat.

Unsaturated fats

Unsaturated fats usually come from plant sources such as safflower, sesame, sunflower, flaxseed, walnut, corn. There are also animal sources of unsaturated fat such as fish. These oils contain omega-3 and omega-6 fatty acids, and are essential in the body. The FDA recommends that up to 20 to 35 percent of daily calorie intake can come from unsaturated fats (monounsaturated and polyunsaturated).

Trans fats

Trans fats are known as non natural man made fats. Most trans is made synthetically by hydrogenating (adding hydrogen) to vegetable oils to make them semi-solid. This helps to increase their shelf-life and improve flavor. Trans fat is found in margarine, shortening, and in most processed foods.

Studies have shown that trans fat is unhealthy and should be avoided. However, naturally occurring trans fat like animal fat is less harmful than synthetic (hydrogenated) oil.

And while some trans fat may be labeled as cholesterol-free, studies show that consumption of trans fat causes an increase in low density lipoprotein (LDL) in the body. This leads to an increase in the levels of bad cholesterol. At the same time, trans fat causes a decrease in high density lipoprotein (HDL), and good cholesterol.

As a result, consumption of trans fats leads to poor cardiovascular health, including coronary heart disease. According to the American Heart Association, eating trans fats increases the risk of coronary heart disease and stroke, as well as the risk of type 2 diabetes.

Why trans fats are bad for men’s testosterone production and health

As indicated above, consumption of trans fats has a negative effect on general health, and on men’s health in particular. They adversely affect testosterone production.

In a study conducted on three successive generations of Wistar rats, by the Institute of Physiology of the Czechoslovak Academy of Sciences, Prague; and published by the National Institutes of Health, hydrogenated fats (trans-fats) were found to reduce serum testosterone levels and sperm production in males.

The study also found that consumption of trans fat reduced the number of babies born, interfered with the female estrous cycle, and increased the gestation period.

A human study conducted in Spain involving 223 male students aged 18 to 23 found that consumption of trans fats is inversely proportional to sperm count. In this study, 37 percent of the participants taking the highest amounts of trans fat recorded the lowest sperm count. 15 percent of these men were also found to have lower testosterone levels and 4 percent lower seminal fluid volume.

The study results are similar to those involving rats in which supplementing with trans fatty acids led to impaired reproduction and accumulation of trans fats in the testis.

How trans fat reduces testosterone production

Trans fat adversely affects general health. It particularly decreases testosterone levels in men by interfering with various processes including the following:

  • Increases LDL levels while decreasing HDL
  • Increases blood insulin levels and consequently, the risk of developing diabetes
  • Decreases immunity as it lowers cells’ vitamin B response
  • Lowers red blood cells’ insulin response
  • Inhibits membrane related enzymes functions which decreases conversion of linoleic acid to arachidonic acid
  • Increases free radical formation
  • Interferes with the enzymes that metabolize carcinogenic chemicals and drugs in the body
  • Interferes with the conversion of plant omega-3 fatty acids to omega-3 tissue fatty acids
  • Increases total serum cholesterol levels beyond 20 percent
  • Alters adipose cell size, amounts and fatty acid composition

Types of foods containing trans fats

When you cook your food, you have a choice of the oil or fat to use. However, when you eat ready made food, you have to contend with whatever oil and other products used in its preparation. And while it may not be practical to avoid eating ready made food, you can take the initiative to make healthy choices.

The following foods are laden with large amounts of trans fats and should be avoided:

  • Fried foods
  • Fast foods
  • Non-dairy creamer
  • Doughnuts
  • Margarine
  • Microwave popcorn
  • Many dessert mixes
  • Many frozen foods

If you have to eat any of these or similar foods, make sure you read the labels carefully to ensure that you are not eating too much trans fat.

In Conclusion

You need fat for your overall health and for testosterone production. However, trans fat, or hydrogenated fats are an unhealthy type of fat made by artificially altering the structure of vegetable oils. This change means that trans fats are harmful to your health. They affect your body in many negative ways, including decreasing your testosterone production, increasing your chances of developing diabetes and heart disease. For these reasons, you should avoid eating trans fat and products containing it to improve your health and boost your testosterone levels.


American Heart Association;
National Institutes of Health;,