As a primary male sex hormone, testosterone is essential for sexual development, muscle growth, and health. Testosterone can be classified as either endogenous or exogenous.
To put it simply, the body produces endogenous testosterone, whereas exogenous testosterone is from external sources, such as testosterone replacement therapy (TRT).
But a deeper understanding of endogenous and exogenous testosterone is important when considering testosterone therapy, knowing your levels, or looking to optimize your hormonal health.
In this guide, you’ll learn the relationship between exogenous vs endogenous testosterone, including their differences, reasons to explore exogenous treatments, and how to optimize your levels.
Key Takeaways:
- Endogenous testosterone is naturally produced by the body, while exogenous testosterone comes from external medical treatments.
- Exogenous testosterone treatments like TRT can effectively treat hypogonadism, but can cause infertility, cardiovascular risks, and hormonal imbalances.
- Natural endogenous testosterone production can be optimized through lifestyle factors like exercise, diet, sleep, and stress management.
- The choice between endogenous and exogenous testosterone should be based on individual health needs and made under medical guidance.
Exogenous vs endogenous testosterone
Normal physiological functioning requires endogenous testosterone, which the body manufactures naturally.
Men with clinically confirmed low testosterone may be prescribed exogenous testosterone therapy to address symptoms and improve quality of life.
Measuring endogenous testosterone levels is essential for diagnosing conditions like primary or secondary hypogonadism, or other hormonal imbalances affecting reproductive health or overall well-being.
Determining whether to take exogenous testosterone is best made under the guidance of a licensed physician.
The right physician and testosterone provider will evaluate your symptoms and blood test results, communicate the pros and cons of exogenous testosterone therapy that may affect you, and create a safe treatment plan.
What is exogenous testosterone?
Exogenous testosterone is testosterone administered from an external source, such as medication. For example, testosterone replacement therapy (TRT) is prescribed to increase testosterone levels in people with low testosterone due to conditions like hypogonadism.
Exogenous testosterone is available in a number of different formulations, including oral tablets, intramuscular injections, transdermal patches, topical gels, buccal tablets, or subcutaneous pellets.
Determining which type to use is often based on personal preference, convenience, and potential side effects.
Exogenous Testosterone Benefits
1. Improved symptoms of low testosterone
Exogenous testosterone can treat low testosterone symptoms like fatigue, libido, erectile dysfunction, and muscle loss.
After normalizing testosterone levels with TRT, people treated for hypogonadism can experience increased energy, sexual function, and quality of life.
2. Enhanced muscle mass and strength
Testosterone promotes muscle protein synthesis, and many individuals taking exogenous testosterone therapy see notable gains in their lean body mass and athletic performance.
3. Bone density improvement
Low testosterone levels are linked to decreased bone mineral density and an increased risk of osteoporosis.
Research shows that TRT can improve bone mineral density, reduce the risk of fractures, and improve overall bone health in men with low testosterone levels.
4. Potential psychological benefits
Some research suggests that exogenous testosterone may have a positive impact on mood and brain function.
Testosterone has been associated with improved spatial ability, verbal memory, and overall cognitive performance. But more research is needed to understand these effects fully.
Exogenous Testosterone Downsides
1. Infertility risk
One potential risk of exogenous testosterone is suppression of the hypothalamic-pituitary-gonadal (HPG) axis.
This decreases production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels.
As a result, spermatogenesis and endogenous testosterone production can decline, which can lead to lowered sperm count and issues with fertility.
These impacts can be reversible when medication is discontinued, but when it’s used over a long period of time, the fertility issues can be longer lasting.
2. Blood clot risk
Taking exogenous testosterone can sometimes lead to hormonal imbalances within the body.
One potential issue is increased hematocrit levels, which can thicken the blood and increase the risk of blood clots and cardiovascular issues.
3. Uncomfortable side effects from medication delivery
Some exogenous testosterone delivery systems can be uncomfortable. For example, some users find TRT injections painful.
TRT patches and gels may cause irritation or rashes. Buccal pills might irritate gums and alter taste.
Remember, TRT providers that offer many types of testosterone therapy and work with you to find the right treatment with minimal side effects are key for having success with your testosterone therapy.
Exogenous Testosterone Treatments
1. Testosterone replacement therapy (TRT)
Doctors often prescribe exogenous testosterone for men with low testosterone.
Optimizing testosterone levels with TRT addresses symptoms of hypogonadism and improves overall health.
Testosterone deficiency can cause issues like erectile dysfunction, decreased libido, muscle mass, strength, and bone mass, as well as increased body fat, and impaired memory, mood, attention, and sleep.
2. Anabolic steroid use
Athletes and bodybuilders often use exogenous testosterone and other anabolic steroids to enhance performance and build muscle mass, but this type of use is unlawful without a prescription.
Serious health risks can occur as well if misused, such as liver damage, cardiovascular issues, and hormone imbalances.
What is endogenous testosterone?
Endogenous testosterone is the testosterone your body naturally produces.
In men, it’s mainly produced in the testes, as well as in the adrenal glands in smaller amounts.
The production of endogenous testosterone in the body is regulated by the HPG axis, which plays a crucial role in sexual development, muscle growth, and overall health.
Endogenous testosterone functions
1. Sexual development and function
Endogenous testosterone is essential for the development and function of male reproductive organs, like the testes, prostate, and seminal vesicles.
It also helps develop secondary sexual characteristics, including muscle growth, body hair, and voice deepening. Healthy testosterone levels are necessary for maintaining a healthy libido and erectile function in men.
2. Spermatogenesis
Endogenous testosterone is crucial for sperm production. It helps regulate the function of Sertoli cells in the testes, which support sperm development.
Adequate testosterone levels are essential for maintaining sperm production and fertility.
3. Muscle growth and strength
Testosterone increases muscle mass and strength by stimulating protein synthesis.
4. Bone health
Endogenous testosterone is vital in maintaining bone density and other measures of bone health, like bone mineralization.
Adequate testosterone levels help prevent osteoporosis and reduce the risk of fractures among men.
5. Mood and cognitive function
Testosterone plays a role in mood regulation and cognitive functions.
Low levels of endogenous testosterone have been linked to mood changes like mood swings, depression, irritability, and anxiety.
In men with testosterone deficiencies, maintaining optimal testosterone levels may help improve mood stability and overall mental well-being.
Endogenous vs. exogenous testosterone: Different types at different times
Endogenous testosterone is crucial for maintaining various bodily functions and overall well-being throughout a man’s life, such as sex drive, fat distribution, strength and muscle mass, red blood cell production, sperm production, and bone mass.
However, factors like age and genetics can cause endogenous testosterone decline that’s difficult to recoup even with changes to exercise, diet and sleep habits.
Exogenous testosterone treatments are valuable for recovering the benefits of healthy testosterone levels as long as your treatment is supervised and provided by physicians and reputable pharmacies.
The first step is knowing your testosterone levels. At-Home Lab Testing measures total testosterone, free testosterone, SHBG, LH, FSH, estradiol and other important men’s health markers.
Get started now and know it before you grow it.
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