Low Testosterone in Men | The Definitive Clinician’s Guide
Written By Kobi Nathan, Pharm.D., M.Ed., CDP, BCGP, AGSF
Sleep Disorders
November 1, 2023

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Testosterone deficiency or Androgen deficiency (AD) occurs when testosterone production is reduced in men, also more widely known as “low testosterone” or “Low T.”

Testosterone is the primary sex hormone produced in the testes.

Testosterone helps to develop and maintain “male” sex characteristics.

These include, among other things, sperm production, sexual function, bone density, body hair, and facial hair.

Testosterone plays a vital role in many bodily functions, but a decline in testosterone may occur with normal aging.

After 40, total testosterone level in the blood declines by 0.4 to 2.6 percent yearly.

These decreases in testosterone parallel reductions in bone and muscle mass, sexual function, and physical capacity are seen with normal aging.

Additionally, low testosterone levels can affect certain metabolic diseases such as obesity and diabetes [1].

What is considered “Low Testosterone”?

Testosterone levels are measured in nanograms per deciliter (ng/dL). “Normal” levels are defined as 280 to 1100 ng/dL.

Low testosterone is below 300 ng/dL.

How common is androgen deficiency (low testosterone) in men?

Most older men have sufficient levels of testosterone, but approximately 10 to 25 percent of men have low testosterone (less than 300 ng/dL).

Doctors usually do not routinely check testosterone levels, so sometimes, men do not know they have low testosterone.

One study found that 5.6 percent of men 30 to 79 years of age have androgen deficiency.

It also found that the prevalence of androgen deficiency increases with age [2].

Why does testosterone deficiency occur?

As aforementioned, the aging process can bring on low testosterone levels.

However, conditions that affect the testes, hypothalamus, and pituitary gland can also lower hormone levels.

Risk factors that may affect these parts of the body include:

  • Genetics
  • Tumors and/or cancer
  • Surgery
  • Radiation
  • Trauma to or torsion (twisting) of the testes
  • Medications (e.g. ketoconazole, steroids)
  • Critical illness
  • Infection

The video below from the popular YouTube channel “Doctor ER” describes low testosterone signs, symptoms, and treatment:

Low testosterone and symptoms in men

Low levels of testosterone result in a wide variety of symptoms because multiple systems in the body are affected.

Your symptoms of testosterone deficiency will depend on your age, comorbidities, and environmental, genetic, and sociocultural factors.

Men with low testosterone may experience the following:

  • Reduced testicular volume
  • Reduced libido (sex drive)
  • Erectile dysfunction (sexual dysfunction)
  • Enlargement of the breast tissue
  • Reduced pubic and armpit hair
  • Hot flashes
  • Heart disease
  • Reduced height
  • Reduced muscle mass
  • Reduced bone mass
  • Lack of concentration
  • Moodiness
  • Reduced energy


FDA Registered facility, NSF cGMP compliant, Natural Products Association Certified, USDA Organic Certified, US Pharmacopeia Certified, Independent Lab Certified, among many others!

Diagnosis of low testosterone in men

Providers diagnose low testosterone based on your signs and symptoms and a blood test.

You will get a blood test in the morning, typically on two separate occasions.

This is because testosterone levels peak in the morning and lower in the evening.

If you were to take a testosterone level at night, many healthy men would have a level below what experts consider normal.

Your doctor may perform other exams if they suspect your AD is due to an underlying condition.

They may order other blood tests, an MRI scan, or genetic testing to rule out other possibilities or medical conditions.

If you need to have your testosterone levels checked, I always recommend that you talk to your doctor.

However, there are circumstances where this is not always possible.

Sometimes, it is more feasible to get your blood work done at a third-party facility.

Some reasons you might want to do this are:

  • You do not have insurance, or your insurance provider requires a referral from your provider
  • You want to avoid cost surprises (no hidden costs)
  • You want a service that is very Affordable – helpful for those with no insurance or who have high deductibles
  • You want to walk into the lab and do not want to hassle with scheduling appointments

HealthLabs.com takes care of all that, is reputable, and you pay for the test and get your results in 1-3 business days.

To learn more about the differences between at-home and clinical testosterone tests, read my article here.

How do you treat low testosterone?

Men with symptoms of androgen deficiency and low testosterone levels can receive testosterone treatments.

The goal of treatment is to maintain sexual function and characteristics (e.g., testicular size and erectile function) and improve quality of life.

There are multiple types of testosterone therapy available to manage low testosterone.

Different treatments have different formulations and delivery systems.

You and your doctor should have a conversation about what regimen is the best for you.

Below, we provide an overview of the types of therapies available:


Types of Testosterone Therapies Available

Intramuscular (in the muscle)Testosterone enantate
Testosterone cipionate
Testosterone undecanoate
50 to 200 mg every seven to 14 days
50 to 200 mg every seven to 14 days
750 mg at 0 and 4 weeks and then every ten weeks thereafter
Jantezo: 158 mg to 396 mg twice daily
OralTestosterone undecanoateCapsuleTestosterone undecanoate: 40 to 120 mg daily
Topical (via the skin)1% Gel (e.g., AndroGel 1%, Testim, Vogelxo)
1.62% Gel (e.g., AndroGel 1.62%)
2% Gel (e.g., Fortesta)
2% solution (e.g., Axiron)
Transdermal system (e.g., Androderm)

50 to 100 mg daily applied to the shoulders or upper arms
20.25 to 81 mg daily applied to the shoulders or upper arms
10 to 70 mg daily applied to the thigh
30 to 120 mg daily applied to the axilla (armpit)
2 to 6 mg daily
Buccal (applied to upper gum)Buccal (e.g., Striant)Patch30 mg controlled-release (CR) patch applied twice daily to the upper gum
NasalGel (e.g., Natesto)GelOne pump in each nostril three times a day
Subcutaneous (under the skin)Injection (e.g., Xyosted)
Pellet (e.g., Testopel)
Implant under the skin
50 to 100 mg once weekly
75 mg per pellet, 6 to 12 pellets every three to four months [5,6]

In general, testosterone products can cause the following side effects:

  • Increased blood pressure
  • Enlargement of the prostate

Testosterone Replacement Options

Testosterone Injections

Injectable testosterone does not maintain consistent testosterone levels in the blood.

This can cause fluctuations in mood, energy levels, and libido.

Additional side effects may include injection site pain, coughing, and erythrocytosis (high blood cell count).

The testosterone propionate formulation is contraindicated if you have a bleeding disorder.

Oral Testosterone

Oral testosterone is convenient for patients because it can be taken by mouth.

However, experts do not usually recommend the oral formulation.

With this formulation, testosterone concentrations can fluctuate in the blood.

This can cause you to have variable side effects.

Side effects of oral testosterone may include:

  • Headache
  • Indigestion
  • Nausea
  • Burping
  • Diarrhea
  • Swelling nausea
  • Increased red blood cell count
  • Increased hematocrit (measures the number of red blood cells in the blood)
  • Increased blood pressure

Oral capsules usually need to be taken twice daily, which may be inconvenient.

After meals, you should take oral testosterone for the best absorption.


The buccal testosterone formulation is applied to the upper gum above the incisor teeth.

These teeth are in the front of your mouth.

You must replace the buccal formulation every 12 hours.

Potential side effects of buccal testosterone include:

  • Increased levels of prostate-specific antigen (PSA, a substance used to screen for prostate cancer) in the blood
  • Increased hematocrit
  • Gingivitis (a mild gum disease)
  • Mouth and gum irritation
  • Emotional changes
  • Changes to taste

Topical Testosterone

Topical formulations of testosterone are convenient for patients.

The application site will vary depending on the type of product.

The cons of topical testosterone usually have to do with skin irritation.

Common side effects include:

  • Skin blistering at the application site
  • Itching at the application site

Skin rash is very commonly seen with the patch formulation.

If you experience irritation, your doctor may prescribe you triamcinolone cream.

This cream decreases irritation without compromising the absorption of testosterone.

The gel formulation has some additional considerations.

You risk transferring the gel to children or partners when using testosterone gel.

Therefore, you must cover the application site after use and wash your hands.


Testosterone also comes in a pellet formulation.

Your doctor can perform a simple surgical procedure to place the pellets under your skin.

These pellets can maintain testosterone levels at normal concentrations for up to six months.

Disadvantages of pellets include infection and scarring at the insertion site.

Additionally, pellets can spontaneously expel from the skin.

A subcutaneous injection formulation is also available.


Experts do not widely recommend testosterone via the nasal route.

If used, intranasal testosterone is dosed three times daily.

A common side effect of intranasal testosterone is high blood pressure.

What else can I expect from testosterone therapy?

In addition to formulation-specific side effects, testosterone can generally affect multiple organ systems and bodily processes.

In terms of sexual function, you may experience increased sexual thoughts, libido, and erections.

Testosterone can also change your body composition.

For example, it may increase your lean body mass and decrease body fat.

Sometimes, these changes can improve physical function.

Other studies have also demonstrated improved mood, energy, and quality of life with testosterone supplementation.

How is testosterone therapy monitored?

Your provider will likely evaluate your testosterone treatment three to six months after starting therapy.

They will check your testosterone blood concentrations in the morning to ensure your levels are within normal range.

Your provider may need to adjust your dose to obtain an appropriate level.

Your provider will also evaluate you for symptom improvement.

They may also monitor your hemoglobin and hematocrit, lipid, and prostate-specific antigen levels.

Who should not receive hormone replacement therapy?

Individuals who should not receive testosterone replacement therapy include those with the following:

  • Breast cancer
  • Prostate cancer
  • Certain abnormal findings on a prostate exam
  • A high prostate-specific antigen level in those who are high-risk
  • Certain severe urinary tract symptoms (e.g., incomplete bladder emptying, straining)
  • Uncontrolled congestive heart failure
  • Untreated sleep apnea

Men with tumors responsive to hormones, such as breast and prostate cancers, should not use testosterone therapy.

Additionally, if you have a strong family history of these cancers, you may have to avoid testosterone products.

Your provider may perform certain assessments to evaluate your risk for prostate issues.

For example, they may perform a rectal exam to see if your prostate is abnormal.

You may also get a blood test to measure PSA.

If abnormal, you may not be able to use testosterone replacement therapy.

Additionally, testosterone treatment can worsen certain conditions, such as obstructive sleep apnea, polycythemia (high concentration of red blood cells in the blood), and congestive heart failure.

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