Low testosterone symptoms in men: which ones point to hormones

The short answer

Low T symptoms can include low sex drive, fewer spontaneous erections, loss of body hair, low energy or low mood. Only some of these point clearly to hormones, because fatigue and low mood have many other causes. Guidelines diagnose low testosterone only when symptoms come with consistently low results on at least two early-morning, fasting blood tests.

Key takeaways

• The guideline's specific signs include loss of body hair, very small testes and incomplete sexual development; fatigue and low mood are nonspecific.
• Symptoms alone cannot diagnose low testosterone. The Endocrine Society calls for at least two early-morning, fasting blood tests.
• The Endocrine Society cites a common clinical threshold near 300 ng/dL, but labs measure differently, so one number is not a diagnosis.
• Age alone is not a diagnosis. The Endocrine Society uses the same diagnostic approach for men of any age.
• Testosterone therapy can raise blood pressure and red blood cell counts and reduce sperm production, so it needs regular monitoring.

What are the symptoms of low testosterone?

The Endocrine Society's guideline sorts the symptoms and signs of low testosterone into three groups^[1]. The specific group includes loss of body hair and very small testes. The suggestive group includes low sex drive, fewer spontaneous erections or erectile dysfunction, breast discomfort or enlargement, and hot flushes. The nonspecific group covers low energy, low mood, poor concentration, poor sleep, less muscle and more body fat^[1].

If erection problems are your main concern, our page on erectile dysfunction care covers them in more depth.

Which symptoms point to hormones, and which usually don't?

In a July 16, 2026 statement, the Endocrine Society said symptoms alone are not diagnostic of low testosterone^[2]. The guideline's specific signs point most directly at hormones^[1]. Suggestive symptoms, such as low sex drive and erection problems, can also come from low testosterone, and both are on the guideline's testing list below^[1]. Still, the Society notes that low energy, libido and mood are common in aging men and have many causes^[2].

The Endocrine Society says clinicians should first rule out reversible contributors, such as obesity and medicines like corticosteroids or opioids^[2]. Low testosterone levels also turn up often in men who have no symptoms or signs at all^[1]. A low result without symptoms does not meet the guideline's definition of low testosterone, which requires both^[6].

The guideline lists situations where low testosterone is common enough that measuring it is suggested^[1]:

• low libido or erectile dysfunction
• infertility
• osteoporosis or a fracture from a minor injury
• a pituitary mass, radiation to the pituitary region, or another disease of that area
• treatment with medicines that affect testosterone, such as opioids and glucocorticoids
• weight loss linked to HIV

Fatigue sits in the nonspecific group^[1]. Feeling tired all the time deserves a medical look, but on its own it does not point to testosterone^[2]. In a trial of older men with low testosterone, a year of testosterone gel gave no significant benefit for vitality compared with placebo gel; the treatment section below has the details^[3].

Does low testosterone cause weight gain?

Low testosterone is linked with more body fat, and extra weight can also lower testosterone^[1][2]. The guideline lists more body fat and less muscle among the nonspecific signs of low testosterone^[1]. The Endocrine Society names obesity as a reversible contributor to low testosterone that clinicians should rule out first^[2]. The guideline also names obesity, diabetes and sleep disorders, including obstructive sleep apnea, among conditions that affect testosterone^[1].

When low testosterone is properly diagnosed, is due to being overweight or obese, and has no other identified cause, the Endocrine Society says weight loss is typically the first-line therapy^[2].

What causes low testosterone in men?

Low testosterone comes from two broad sources. The testicles may not make enough, for reasons such as genetic problems or chemotherapy, or the hypothalamus and pituitary, the brain structures that control the testicles, may not signal them properly^[4]. Some medicines and conditions also lower levels, including opioids, glucocorticoids, acute illness and poor nutrition^[1].

The label for one FDA-approved testosterone injection describes the same two groups^[5]. Primary hypogonadism means testicular failure, from causes such as undescended testes, torsion of both testes, orchitis (inflammation of the testes) or surgical removal of the testes. Hypogonadotropic hypogonadism includes injury to the pituitary or hypothalamus from tumors, trauma or radiation^[5].

Once low testosterone is confirmed, the guideline recommends more testing to find the cause^[6]. A pituitary mass, for example, is on its list of conditions where low testosterone is common^[1].

The Endocrine Society says terms like "age-related," "late-onset" and "functional" hypogonadism are hard to define and blur the line between treatable disease and normal aging^[2].

How do you know if you have low testosterone?

Blood tests, read alongside your symptoms, answer the question "Do I have low testosterone?" The Endocrine Society says a healthcare provider should base the diagnosis on at least two early-morning, fasting testosterone tests^[2]. Its guideline recommends diagnosing low testosterone only when symptoms and signs come with unequivocally and consistently low levels, and confirming a first low result with a repeat morning fasting test^[6].

The guideline recommends against routine screening of men in the general population^[1], and the Society's 2026 statement found too little evidence to support population-level screening of men without symptoms^[2]. When symptoms do call for testing, it usually follows these steps:

• The first test is a fasting morning total testosterone, measured with an accurate and reliable assay^[6].
• A repeat morning fasting test confirms a low result^[6].
• When total testosterone is near the lower limit of normal, or a condition alters sex hormone-binding globulin (a blood protein that binds testosterone), the guideline recommends measuring free testosterone as well^[6].
• Testing is put off while you have, or are recovering from, an acute illness, and during short-term use of medicines such as opioids that suppress testosterone^[1].

Testing usually starts with a testosterone blood panel.

What is considered low testosterone?

No single number defines low testosterone for everyone. The Endocrine Society describes a common clinical threshold near 300 ng/dL, applied to at least two early-morning, fasting tests^[2]. It also warns that testing is often inaccurate: with non-standardized assays, the same blood sample can read "low" or "normal" depending on the lab and method^[2].

Research trials set their own entry levels. TRAVERSE enrolled men with testosterone less than 300 ng per deciliter on two fasting tests^[7], and the Testosterone Trials enrolled men with a serum testosterone less than 275 ng per deciliter^[3]. Those were rules for who could join each study.

The Society says standardized testosterone assays are available and improve diagnosis, and it points to assays certified by the CDC HoST program^[2]. When you get a result, ask which lab ran it and what reference range it uses, because a result read against another lab's range can mislead^[2].

Is low testosterone just part of getting older?

Age alone is not a diagnosis. The Endocrine Society says the approach and definition of the diagnosis is the same for a man of any age^[2]. An older man with low energy needs the same workup as a younger one: symptoms plus consistently low morning tests^[2][6].

What the FDA asked for in June 2026

FDA's testosterone information page, updated June 23, 2026, says FDA requested updates to testosterone prescribing information in June 2026^[4]. The requested updates include removing the limitation of use that says the safety and efficacy of testosterone therapy in men with age-related hypogonadism have not been established. They also revise safety information on prostate cancer and benign prostatic hyperplasia, a noncancerous enlarged prostate^[4].

As of November 1, 2026, FDA describes these changes as requested^[4]. The DailyMed label for one testosterone cypionate injection, last updated June 30, 2025 and checked on October 31, 2026, still says safety and efficacy in men with "age-related hypogonadism" have not been established^[5]. FDA's February 2025 labeling changes had kept that limitation of use^[8]. The same FDA information page says none of the FDA-approved testosterone products are approved for men with low testosterone levels who lack an associated medical condition^[4].

What the Endocrine Society said in July 2026

On diagnosis, the Society's 2026 statement said^[2]:

• Symptoms alone are not diagnostic of hypogonadism.
• A healthcare provider should make the diagnosis from at least two early-morning, fasting testosterone tests, with a common clinical threshold near 300 ng/dL.
• The approach and definition of the diagnosis is the same for a man of any age.
• Clinicians should first rule out reversible contributors, such as obesity and medicines like corticosteroids or opioids.
• The evidence does not support screening whole populations of men without symptoms.

The statement also summarized the risk evidence from the TRAVERSE trials, covered in the next section^[2].

What does treatment involve, and what are the risks?

Treatment comes only after a confirmed diagnosis and a decision made with a licensed provider. The guideline recommends testosterone therapy for men with symptomatic deficiency after a discussion of the benefits, the risks and the monitoring, with the patient involved in the decision^[6]. Testosterone can raise blood pressure and red blood cell counts and can reduce sperm production, so it needs regular monitoring^[8][5].

The Endocrine Society says testosterone at a dose similar to what a man would typically make has clear benefits for men with properly diagnosed hypogonadism caused by a disease of the testes, pituitary or hypothalamus^[2]. In the Testosterone Trials, 790 men 65 years of age or older with a serum testosterone less than 275 ng per deciliter and symptoms received testosterone gel or placebo gel for one year^[3]. Testosterone gave a moderate benefit for sexual function and some benefit for mood and depressive symptoms, with no benefit for vitality or walking distance^[3]. The trial had too few participants to draw conclusions about risks^[3].

TRAVERSE, a trial designed to study heart risk, enrolled 5246 men aged 45 to 80 who had symptoms of hypogonadism, testosterone less than 300 ng per deciliter on two fasting tests, and heart disease or a high risk of it^[7]. They were randomly assigned to daily testosterone gel or placebo gel. Men were treated for 21.7 months (mean duration of treatment) and followed for 33.0 months (mean follow-up)^[7]. A primary cardiovascular event, meaning death from cardiovascular causes, a nonfatal heart attack or a nonfatal stroke, occurred in 7.0% of the testosterone group and 7.3% of the placebo group (hazard ratio 0.96), and the researchers concluded testosterone was noninferior to placebo for major adverse cardiac events in these men^[7]. The testosterone group had more atrial fibrillation, acute kidney injury and pulmonary embolism^[7].

The Society's 2026 statement adds that the TRAVERSE trials showed roughly a 50% relative increase in pulmonary embolism and more bone fractures among men treated with testosterone^[2]. In the Society's words, "Long-term safety (including for prostate cancer) remains unestablished"^[2].

The guideline also advises against starting testosterone in men with breast or prostate cancer, a palpable prostate nodule or induration (a lump or hardened area), a raised PSA (prostate-specific antigen) level without further urological evaluation, elevated hematocrit, untreated severe obstructive sleep apnea, severe lower urinary tract symptoms, uncontrolled heart failure, a recent heart attack or stroke, or thrombophilia, a tendency to form blood clots^[6]. Its monitoring plan covers symptoms, side effects, testosterone and hematocrit levels, and prostate cancer risk during the first year^[6]. The Endocrine Society likewise says screening and monitoring are needed once therapy starts^[2].

For more, see testosterone therapy for lab-confirmed low testosterone, how testosterone therapy is monitored for safety and the testosterone important safety information.

What this means for you: when to see a clinician

See a clinician if symptoms from the guideline's specific or suggestive groups persist: loss of body hair, a drop in sex drive or spontaneous erections, breast tenderness or enlargement, trouble fathering a child, or a fracture from a minor injury^[1]. Low energy or low mood alone is still worth a visit, though the clinician will look at other causes too^[2].

Before and during the visit:

• Bring a list of every medicine you take. Opioids and corticosteroids are among the contributors the Endocrine Society says to rule out first^[2].
• Expect an early-morning, fasting blood test and a repeat test to confirm a low result^[2][6].
• If you are sick or recovering from an acute illness, wait until you are well before testing^[1].
• If you plan to have children soon, say so before any treatment is discussed^[6].
• Ask whether the lab uses a CDC HoST-certified testosterone assay^[2].

A licensed provider reviews your symptoms and morning labs and decides whether treatment is appropriate. To see what an evaluation involves, read how a visit works, in person or by telehealth; depending on your state, an in-person exam may be required.

If you already use testosterone, get medical help right away for pain, swelling, warmth or redness in a leg, or for sudden shortness of breath. The label tells clinicians to check those symptoms for a blood clot in the leg or lung^[5]. Also report erections that are too frequent or that do not go away^[5].

Questions

Sources

1. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline (full text, Tables 3-4, sections 1.1-1.4). Oxford Academic (J Clin Endocrinol Metab). Accessed 2026-10-31. academic.oup.com/jcem/article/103/5/1715/4939465
2. Statement on Testosterone Replacement Therapy | Endocrine Society. Endocrine Society. Accessed 2026-10-31. www.endocrine.org/news-and-advocacy/news-room/2026/statement-on-testosterone-replacement-therapy
3. Effects of Testosterone Treatment in Older Men - PubMed. National Institutes of Health. Accessed 2026-10-31. pubmed.ncbi.nlm.nih.gov/26886521/
4. Testosterone Information | FDA. U.S. Food and Drug Administration. Accessed 2026-10-31. www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/testosterone-information
5. DailyMed - TESTOSTERONE CYPIONATE injection, solution. DailyMed, U.S. National Library of Medicine. Accessed 2026-10-31. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b8ac5e07-b7e3-4a60-b0d1-8b1f3ad0c478
6. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline - PubMed. National Institutes of Health. Accessed 2026-10-31. pubmed.ncbi.nlm.nih.gov/29562364/
7. Cardiovascular Safety of Testosterone-Replacement Therapy - PubMed. National Institutes of Health. Accessed 2026-10-31. pubmed.ncbi.nlm.nih.gov/37326322/
8. FDA issues class-wide labeling changes for testosterone products | FDA. U.S. Food and Drug Administration. Accessed 2026-10-31. www.fda.gov/drugs/drug-alerts-and-statements/fda-issues-class-wide-labeling-changes-testosterone-products