Low Testosterone Symptoms: Signs of Low T and When to Get Tested

Low testosterone, or low T, is common as men age, and many signs overlap with stress, poor sleep or other illness. This page sets out the signs of low T, what doctors mean by male hypogonadism, how normal testosterone levels are judged, and what to do next. We do not give doses or treatment plans. A clinician decides.

Signs of low T

MedlinePlus, the National Library of Medicine's health site, lists these signs of low testosterone in adult men:

• Low sex drive.
• Erectile dysfunction (ED), which means trouble getting or keeping an erection.
• Infertility, or trouble getting a partner pregnant.
• Enlarged breasts.
• Lack of face or body hair.
• Thinning bones or anemia (a low red blood cell count) without a known cause.
• Loss of muscle mass.

Its page on hypogonadism adds that in men, low hormone levels can bring "Breast enlargement", "Muscle loss" and "Decreased interest in sex (low libido)" (MedlinePlus: hypogonadism, read 14 November 2026). It also lists "Impotence", "Infertility", "Osteoporosis" and "Weakness". Osteoporosis means weak, brittle bones.

Many men also report low energy, low mood or poor focus. These are real problems, but they have many causes, so they point to low T less clearly than the signs above.

Why symptoms alone are not enough

The American Urological Association (AUA) is the main US body for urologists. Its testosterone guideline sets a two-part test. It says "to be testosterone deficient is to have low testosterone levels combined with symptoms or signs that are associated with low serum total testosterone" (AUA testosterone deficiency guideline, read 14 November 2026).

The AUA also warns that the symptoms "are very non-specific and can be manifestations of other conditions (e.g., chronic fatigue, chronic stress, a depressed state)". In plain words, tiredness and low mood can come from many places. So a doctor wants both the symptoms and a low blood level before calling it low T.

What is male hypogonadism?

Male hypogonadism is the medical name for low testosterone caused by a problem in the body that makes it. Hypo means low, and gonads are the testes. There are two main kinds:

• Primary hypogonadism. The testes themselves do not make enough. The testosterone label lists causes such as "testicular failure due to cryptorchidism, bilateral torsion, orchitis" (DailyMed: Depo-Testosterone label). Cryptorchidism is an undescended testicle, and orchitis is swelling of the testicle.
• Secondary (central) hypogonadism. The testes are fine, but the brain does not send the signal to make testosterone. The same label lists "pituitary-hypothalamic injury from tumors, trauma, or radiation" as causes.

MedlinePlus notes that a brain tumor near the pituitary can also cause "Headaches or vision loss". Those signs need a doctor soon, not an online visit.

How normal testosterone levels are judged

There is no single number that fits every lab. Each lab sets its own normal range, and the result comes with that range printed beside it. What matters most is how the test is done.

The testosterone label tells prescribers to confirm low T "by ensuring that serum testosterone concentrations have been measured in the morning on at least two separate days and that these serum testosterone concentrations are below the normal range" (DailyMed: Depo-Testosterone label). Morning matters because levels are highest early in the day.

Large trials show the cut-off doctors often use. The TRAVERSE trial enrolled men "who reported symptoms of hypogonadism and had two fasting testosterone levels of less than 300 ng per deciliter" (Lincoff et al., NEJM 2023, PubMed). That is a trial rule, not a personal target. Your own result should be read by the clinician who ordered it, against your lab's range.

Does testosterone drop with age?

Yes, but slowly. MedlinePlus says "Men normally have lower testosterone as they age. However, the decline in hormone levels is much less than in women." (MedlinePlus: hypogonadism).

Whether age-related low T should be treated is still debated. The testosterone label says its safety and efficacy, which means how well it works, "in men with “age-related hypogonadism” (also referred to as “late-onset hypogonadism”) have not been established" (DailyMed: Depo-Testosterone label). In the Testosterone Trials of men 65 and older, a year of gel "had a moderate benefit with respect to sexual function and some benefit with respect to mood and depressive symptoms but no benefit with respect to vitality or walking distance" (Snyder et al., NEJM 2016, PubMed).

How to get tested for low T

A total testosterone blood test is the usual first step. MedlinePlus calls total testosterone "the most common type of test". You can get one through your own doctor, at a lab, or with an at-home kit sold by some online programs. Most online testosterone programs require a test before they prescribe anything.

Our testosterone test cost guide prices the options before you commit to a program. If a program offers treatment without a blood test, that skips what the label asks for.

Treatment options for low T

If tests confirm low T, a clinician may discuss options. The two main routes sold online are:

• Testosterone therapy (TRT). This adds testosterone as an injection, gel, cream or capsule. Our what is TRT guide explains how it works, and our TRT side effects guide covers the label warnings.
• Enclomiphene or clomiphene. These pills push your own body to make more testosterone. Our enclomiphene vs TRT guide compares the two.

If ED is your main problem, low T may not be the cause at all. Our guide to erectile dysfunction causes covers the other reasons. The cheapest low-testosterone plan we track today, testosterone or enclomiphene, is Strut Health at $79, and every program is on our TRT price page and testosterone hub.