Hormones like testosterone, estrogen, and progesterone can have an important impact on both male and female health.
In the case of testosterone, this hormone helps regulate libido, bone mass, muscle mass, and red blood cell production, among other things. If you’re on a weight loss journey, you may have heard that losing weight can impact your body’s testosterone levels.
But what’s the truth? Does being overweight impact testosterone levels? And can testosterone therapy contribute to greater weight loss?
There’s a lot of misinformation out there when it comes to weight loss, so let’s cut through the fat. Read on to learn all about the link between testosterone levels and your weight.
Why Is Testosterone Important?
Testosterone is the primary male sex hormone, although females do make some testosterone as well. Testosterone has many roles within the body.
It particularly is important for:
- Mood, behavior, and cognition
- The development of the penis and testes
- The deepening of the voice in men during puberty
- The appearance of facial and pubic hair in men starting at puberty
- Muscle size and strength
- Bone growth and strength
- Sex drive (libido) in men and women
- Sperm production in men
Normal levels and a proper balance between testosterone (along with other androgens) and estrogen is also important for ovarian function in women.
Studies show that androgens in certain concentrations also play an important role in normal brain function, including mood, sex drive and cognitive function.
Weight Loss and Testosterone
Because testosterone plays such an important role within the body, you may be wondering how it affects weight loss and metabolic health.
Low testosterone levels are common in overweight men with prediabetes. In one study, men who made lifestyle modifications such as exercising or strength training to support weight loss found that the prevalence of low testosterone levels decreased.
The increase in testosterone levels was connected to decreasing body weight and waist size. According to the study, losing weight may not only reduce the risk of prediabetic men progressing to diabetes but also appears to increase their body's production of testosterone.
One study investigated the link between testosterone and metabolic health in both men and women. Here’s what they found:
- An increase in testosterone is associated with reduced body fat, lower levels of glucose in the blood, and improved insulin sensitivity in men.
- In women, increased testosterone is associated with increased body fat, higher levels of glucose in the blood, and insulin resistance.
Where lower levels of testosterone increase the risk of developing type 2 diabetes in men, higher levels of testosterone may increase this risk in women.
The Role of Testosterone Therapy in Weight Loss
If testosterone is so beneficial for weight regulation in men, can testosterone therapy help men lose weight? One study aimed to answer this question.
Here’s what they found:
- Long-term testosterone therapy in men with testosterone deficiency appears to be supportive of sustainable weight loss, reduced BMI, and a reduced waist circumference.
- Testosterone therapy may also improve aspects of metabolic syndrome.
- Improvements in weight regulation may be due to improved function of the mitochondria, which are parts of the cell responsible for energy production.
- Participants also experienced increased motivation, which led to increased physical activity that, in turn, improved cardio-metabolic function.
Researchers in this study also had the following key takeaways:
- Low testosterone levels are commonly seen in overweight or obese men who have prediabetes.
- After lifestyle modifications, the prevalence of overweight men with low testosterone levels decreased by nine percent after a year.
- Evidence suggests that weight loss not only helps increase testosterone levels, but also may reduce the risk of prediabetes.
All in all, it seems that testosterone therapy may be beneficial for some men who have low testosterone levels and may support weight loss. Being overweight may impact testosterone levels, but testosterone levels can also impact weight.
Potential Drawbacks of Testosterone Therapy
As we’ve seen, testosterone replacement therapy for those who have low levels may support weight loss. But are there any side effects of testosterone treatment?
Meta-analyses have analyzed many studies that investigated testosterone therapy have found four main adverse effects of this therapy:
- Increased risk of polycythemia, a type of blood cancer.
- An increase in prostate-related events
- A slight reduction in blood levels of HDL, or high-density lipoprotein
- May increase cardiovascular risk in men
Testosterone therapy and questions should always be guided by a qualified medical professional. More research on its effects is still needed, and your individual medical history may need to be considered by a doctor.
Is a Testosterone Imbalance Bad?
An imbalance of testosterone can affect your health in different ways. A testosterone deficiency or other type of imbalance can be caused by aging or certain medical conditions.
The symptoms associated with low testosterone concentrations include:
- Low libido
- Erectile dysfunction
- Diminished cognitive function
- Loss of muscle mass and strength
- Metabolic syndrome
On the other hand, some symptoms associated with high testosterone may include:
- Low sperm counts, plus shrinking of the testicles and impotence
- Heart muscle damage and increased risk of heart attack or cardiac disease
- Prostate enlargement with difficulty urinating
- Liver disease
- Fluid retention
- Weight gain
- High blood pressure and cholesterol
- Increased muscle mass
- Increased risk of blood clots
- Stunted growth in adolescents
- Uncharacteristically aggressive behavior
- Mood swings
In women, the most common cause of a high testosterone level is polycystic ovary syndrome (PCOS). However, it’s important to note that there are many overlapping symptoms and conditions that are associated with both a deficiency and excess of testosterone.
Many of the studies looking at the risks and symptoms of high testosterone levels have concluded that associations in women are less clear than in men.
Your Diet and Testosterone
What about your diet? Does nutrition play a role in testosterone levels? Researchers seem to think so.
Scientists have found that obesity and low serum testosterone levels are interrelated and strongly influenced by dietary factors, though the research is ongoing.
One study found that low testosterone levels, or hypogonadism, are associated with high consumption of bread and pastries, dairy products, and desserts, eating out, and a low intake of homemade foods and dark green vegetables.
Another study, a randomized controlled trial, or RCT, done in obese and/or overweight men involved trialing participants on a very low carb keto diet, or VLCKD to see if it affected their testosterone levels.
The authors found that after undergoing this diet for 12 weeks, the participants significantly reduced their body weight and BMI. And yes, the participants also increased their testosterone levels, and none of them experienced low levels of testosterone at the end of the diet.
Another study investigated the impact of a ketogenic diet versus a traditional western diet on changes in body composition, performance, blood lipids, and hormonal profiles in resistance-trained athletes.
The authors found that those on the keto diet had significantly increased levels of testosterone compared to those who were on the western diet. They also suggest pairing the keto diet with resistance training for improved body composition, physical fitness performance, and hormone levels.
Improving insulin sensitivity may also support weight loss. Some additional tips to improve insulin sensitivity and, thus, testosterone levels may include:
- Meal sequencing, which includes eating your protein and non starchy vegetables before eating carbs.
- Try an earlier eating window to improve your AUC and delta levels.
- Go for a walk or move your body after eating.
- Work with a credentialed dietitian to find the right macronutrient ratio for you.
- Aim for seven to nine hours of sleep per night
- Reduce your stress levels
- Add more colorful fruits and veggies to your diet
As always, work with a doctor or a registered dietitian to assess your needs and customize a dietary and lifestyle approach that works for you.
How Does Testosterone Production Work?
So, is there anything else you need to know about the role of testosterone in the body and how your body produced it?
Testosterone production is controlled by the hypothalamic-pituitary-gonadal (HPG) axis which involves the hormones gonadotropin-releasing hormone (GnRH), luteinizing hormones (LH), and follicle-stimulating hormones (FSH).
In puberty, the hypothalamic-pituitary-gonadal axis plays a major role in regulating testosterone levels and gonadal function. The hypothalamus secretes a hormone called GnRH, or gonadotropin-releasing hormone, which travels to the anterior pituitary.
In response, the anterior pituitary secretes LH, or luteinizing hormone, and FSH, or follicle-stimulating hormone. LH acts on the Leydig cells (located in the testes of the male gonads) to increase testosterone production.
Most testosterone, the major circulating male androgen, is produced in the testes from cholesterol. However, this does not mean that high cholesterol equals high testosterone (human physiology is a little more complex than that).
Testosterone can also be converted to estrogen through aromatase enzymes in target areas including neural tissue, adipose, liver, and bone. In men, estrogen from this reaction is important for the maturation of sperm and libido maintenance.
In women, testosterone and its precursor, androstenedione, are synthesized within the adrenal cortex and ovaries. The remainder of testosterone production occurs in peripheral tissues such as bone, breast, muscle, and fat.
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