The Science Behind TRT Therapy


As men age, they experience lower production of the hormone testosterone, which can mean lower sex drive, hair loss, and lower energy levels. This is part of life and doesn’t mean anything is wrong.

A man doing workout

However, low testosterone can indicate a problem beyond simple aging.  Either way, science allows us to do something about it in the form of testosterone therapy. Knowing how testosterone therapy works is a crucial factor in deciding whether it is right for you.

What Is Testosterone Therapy?

Also called testosterone replacement therapy (TRT), this therapy supplements the testosterone already produced by the male body. TRT works because it governs the amount of the hormone in the body, boosting low levels of testosterone. 

This hormone is essential because it governs several elements of the masculine form, including:

  • Sex drive
  • Muscle mass
  • Lower speaking voice
  • Bone density
  • Sperm production

A man with low testosterone levels (diagnosed through a series of blood tests) will experience a drop in these things and other symptoms. While rarely life-threatening, they do impact the quality of life.

How is Testosterone Therapy Administered?

A man applies gel to the shoulder

Treatment comes in several varieties. Users may apply a gel onto the shoulders or abdomen. It may be injections, or a doctor might prescribe a buccal patch between the cheek and gums. Still, all three medication delivery systems have their pros and cons. [1]

While the gel may offer the steadiest form of delivery, it poses a danger to others. It can cause hair growth and other adverse effects in women if transferred to their skin. The gel form of treatment, however, delivers a regular and reliable supply of testosterone. [2]

The use of injections presents little risk to someone other than the prescribed user coming into contact with the testosterone supplement. However, some men experience a series of ups and downs with this method, as the amount of testosterone spikes with the injection, then gradually fades until it is time for the next dose. Mood shifts may be more problematic for some than others.

The buccal patch can irritate the mouth or gums or cause swelling of the lips. There is a low risk of an adverse reaction to accidentally swallowing the patch. However, this system is also reliable for testosterone delivery. [3]

All three of these delivery methods are specific to prescription testosterone, although over-the-counter medicines are also available. Studies and research support less efficacy, but they are not without merit.

[1] Testosterone Therapy Treatment Types, Uses& Risks

[2] Harvard Health Publishing: A new look at testosterone therapy

[3] Testosterone Buccal

How to Know if Testosterone Therapy is for You?

Generally, doctors prescribe TRT for men suffering from male hypogonadism. This condition occurs when the body does not produce enough testosterone, sperm, or both. It is not the same thing as the natural decline in testosterone production associated with the aging process. However, the same methods can treat that type of low testosterone.

Hypogonadism symptoms may include: decreased energy and sex drive, erectile dysfunction, loss of muscle mass, even gynecomastia (the development of breast tissue in males). Men experiencing these symptoms should consult a physician, as TRT is a possible remedy. [1]

[1] Mayo Clinic: Male hypogonadism -Symptoms and causes

Testosterone Treatment Benefits and Possible Issues

A man with acne

Men with hypogonadism will see symptom improvement with TRT. They may need to remain on the treatment for  life. Still, as long as they continue taking it, they should have normal testosterone levels and enjoy the accompanying benefits. 

Whether TRT delivers the same benefits to men dealing with Low T due solely to aging is up for debate. The Mayo Clinic lists side effects specifically linked to TRT when treating this testosterone deficiency. These include:

  • Lower sperm production
  • A shrinking of the testicles
  • Benign prostate tumors (worsening of prostate cancer already present)
  • Blood clots
  • Acne
  • Sleep apnea-- the onset or the worsening of an existing problem 

These side effects can occur in anyone undergoing TRT. Yet, they seem more pronounced in men using TRT to combat hypogonadism rather than due to natural level decreases due to aging. Choosing TRT for any low testosterone does have its risks. [1]

Dr. Adriane Fugh-Berman of Georgetown University Medical Center in Washington, DC, goes further than the Mayo Clinic. She writes explicitly in the American Academy of Family Physicians editorial that using testosterone treatment to combat the effects of aging is not appropriate.  

She noted that since low testosterone symptoms related to aging do not correlate to low levels due to hypogonadism, the treatments should not be the same. [2]

[1] Mayo Clinic: Testosterone therapy:Potential benefits and risks as you age

[2] American Academy of Family Physicians: Treating Aging with Testosterone

Frequently Asked Questions

Are you looking for more information? Here are a few FAQs about testosterone therapy for men.  

Will TRT make me feel young and vital again?

If you are dealing with hypogonadism, yes, it will. If your testosterone is low because you are older, the jury is out, and much of the evidence is anecdotal.  The American College of Physicians found that some men experience improvement in their sexual functioning. Not much peer-reviewed evidence exists to show increased energy as a direct result.

Does TRT cause hair loss?

It can, but it does not always. Men undergoing TRT who lose hair will begin doing so in the first year of treatment. However, since low and high levels of testosterone are both shown to cause hair loss, it can be argued (and has been) that TRT is not the only factor governing hair loss. Like many medical treatments, you’ll need to see what works for you.

How long does TRT take?

You may begin to notice the effects of TRT in as little as three weeks and even less time in some people.  

How long will I need to be on TRT?

Since TRT does not cure the causes of low T but rather alleviates its symptoms, when you stop treatment, those symptoms will return. So, TRT needs to be taken indefinitely to prevent low T from recurring.

If I’m not older and don’t have hypogonadism, why do I still have low T?

These two causes of low testosterone levels are not the most common causes of Low T. Dr. Frances Hayes, an endocrinologist at Massachusetts General Hospital, wrote for the Harvard Health Review. He states that the number one cause of low T was weight gain.

Dr. Hayes also stated that just a five-point increase on the Body Mass Index (BMI) scale corresponded with testosterone levels of a person ten years older. So the first recommendation is to manage your weight and perhaps a doctor’s visit will be unnecessary.

Testosterone Therapy and You 

When you find yourself dealing with symptoms of low testosterone, you do not have to suffer in silence. Knowing the cause of your low levels is a good starting place on your way to improving your symptoms and quality of life. 

Treatments are available, and while there are side effects that may come into play, these will not affect everyone and will depend on how severe your symptoms are. Consult your physician to learn what options are for you and how you might go about remedying your low testosterone issues.

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