Fatigue, weight gain, decreased sex drive and depression are very common complaints, especially as men age.  There are many diagnoses associated with such symptoms – obesity, diabetes and hypothyroidism are some examples.  They can also be associated with hypogonadism – which in men – is low testosterone or LowT.

What is Testosterone?

Testosterone is a hormone made in the testicles.  It’s production is controlled by other hormones in the pituitary gland, which senses the testosterone level in the body and directs production.  Testosterone is involved in genital development and other sex characteristics such as deepening of the voice, body hair, and sex drive.

How is Testosterone measured?

Testosterone is measured with a blood test.  There are two values that can be checked – total testosterone and free testosterone.  Free testosterone is the amount of hormone circulating that is directly and instantly available to the body, and not tied to another molecule in the system.

Normal levels of total testosterone range from 300-800 mg/dl.  One of the difficulties in measuring testosterone is that the value varies throughout the day and can be affected by a recent meal, exercise or the amount sleep you had prior to the test!

How is Testosterone supplemented?

Testosterone is not digestible, so it must be administered topically as a patch, cream, or gel, or injected into a muscle.  Each method has its pluses and minuses.

Topical medications are convenient, but may cause skin irritation.  There may be irregular absorption of the testosterone through the skin.  Also, if the testosterone is not completely absorbed it can be transferred to someone else’s skin – an important consideration if there are children or women (especially if pregnant).

Injections deliver a more precise dose and there is no risk of transferring the medication to someone else, but an injection every 2-4 weeks may be painful and less convenient – whether done at home or in a physician’s office.

How does Low Testosterone develop?

Damage or dysfunction of the testicles or pituitary gland either from medications, tumors or other problems can cause low testosterone.    Anabolic steroids – those used as performance enhancing drugs in sports – can lower testosterone levels among other side effects.  It was for severe deficiency around early development or testicular damage that synthetic testosterone was initially prescribed and FDA approved for – not for helping aging men feel 30 again.

Testosterone levels normally begin to decline by about 1% per year after age 30 – but this is very variable.  This decline, especially when blood tests became routinely available to check testosterone levels, gave rise to terms like andropause, male menopause or manopause.  In the past 10 years, testosterone use in men over 40 has quadrupled, and has become a multibillion dollar industry.

Similar to hormone replacement therapy (HRT) for women, restoring hormone levels to an earlier age has been marketed as a way of turning back the clock, restoring youth and vigor – and treating some very common, non-specific symptoms.  It wasn’t until after decades of HRT that a large study was done demonstrating that rather than helping improve women’s health, HRT increased rates of heart attacks, stroke, breast cancer and endometrial cancer!

Recently, several studies have been published linking testosterone therapy with an increased risk of heart disease.  These studies have called into question the wisdom of testosterone supplementation in the absence of true hypogonadism.  One study found that in men 65 and older the risk of a heart attack doubles in the first 90 days after starting treatment and goes up by 2-3 times in men under 65 with a history of heart disease.  This and other studies have prompted the FDA to review the safety of testosterone therapy and a large study similar to the one done for HRT is now underway to determine the benefits and harms of testosterone therapy.

How does this affect MY practice?

As with most diagnoses, a good history of symptoms is essential to determine their cause.  How long symptoms have been present, what seems to improve them, what else is going on in one’s life all contribute to weight gain, sex drive, energy and mood.  Diet and exercise habits need to be explored as changes  can have a huge impact on well-being, including raising testosterone levels without supplementation.

After discussing symptoms and a physical exam is performed, lab tests can be ordered.  I usually check a total testosterone first – it is much less expensive and the results come back faster.  If it is low or borderline, adding the free testosterone can be helpful to confirm or rule out the diagnosis.

Once all the data is back, we can review both symptoms and data together to decide if testosterone supplementation is likely to improve how one feels or if there is a different, more likely diagnosis.    Prior to starting supplementation I always check a blood count, cholesterol level, liver, kidney  and sugar tests as well as a PSA.  Supplementation can effect all these things which in turn can have health consequences.  For example, testosterone can cause the prostate to grow and may unmask an undiagnosed cancer – which is why supplementation therapy needs to be monitored.

At follow-up visits we assess the effect of treatment on both testosterone levels and most importantly, symptoms.  If the levels normalize and there is no change in how you feel, then as I wrote in an earlier post (What is a Diagnosis), treatment should be stopped and the diagnosis reconsidered.

The new evidence about the increased risk of heart attack will increase the conversations I have with my patients, especially those over 65 or with a history of heart disease, and likely increase how closely they are monitored.

Numbers from a lab without the context of symptoms don’t make a diagnosis.  Symptoms without the correlation of lab results often can not make a diagnosis.  Treating either in isolation does not improve health.  When used together, solutions can be found.

The path to wellness begins with a proper diagnosis

Published by Eric Goldberg, MD, FACP

I am a Board Certified Internal Medicine physician. I currently practice at and am the Medical Director of NYU Langone Internal Medicine Associates. Posts are my opinion and not medical advice or an official position of NYU Langone Medical Center.

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