Low testosterone is diagnosed when a man has symptoms such as low sex drive or fatigue and two separate early-morning blood tests show low total testosterone. The American Urological Association (AUA) uses a total testosterone below 300 ng/dL as a reasonable cutoff. Symptoms alone aren’t enough, and neither is a single test, which is why lab work always comes before treatment.
What are the symptoms of low testosterone?
Testosterone affects sex drive, energy, muscle, mood, bone and red blood cell production. When levels are low, men may notice:
- Lower sex drive
- Erectile problems, or fewer spontaneous erections
- Fatigue and low energy
- Loss of muscle mass or strength
- More body fat
- Low mood or irritability
- Trouble concentrating
- Less body or facial hair
- Hot flashes
- Thinning bones
Many of these symptoms have other causes too, including poor sleep, sleep apnea, depression, thyroid problems, weight gain, alcohol and some medications. That overlap is exactly why testing matters.
How is low testosterone diagnosed?
The AUA guideline sets out a clear process:
- Symptoms or signs. A diagnosis of testosterone deficiency requires both low levels and symptoms or signs, not one alone.
- Two total testosterone tests. The AUA strongly recommends measuring total testosterone on two separate occasions, both in the early morning.
- A cutoff of about 300 ng/dL. The AUA considers a total testosterone below 300 ng/dL a reasonable cutoff to support the diagnosis.
Other guidelines, including the Endocrine Society’s, use slightly different thresholds, and labs report their own reference ranges. Your provider interprets your results in context, not against a single number.
Why do the tests need to be in the morning?
Testosterone follows a daily rhythm and is usually highest in the morning. It also varies from day to day and can drop temporarily during illness, after poor sleep or with certain medications. A single afternoon test can make normal levels look low, so two morning tests give a more reliable picture.
What other labs might you need?
Once low testosterone is confirmed, the next question is why. Your provider may check:
- Luteinizing hormone (LH), which shows whether the problem starts in the testes or in the signal from the pituitary gland. The AUA recommends measuring LH in men with low testosterone.
- Prolactin, if testosterone is low and LH is low or normal.
- Hematocrit or a blood count, because testosterone therapy can raise red blood cell levels.
- PSA, a prostate screening test, in men over 40 before starting therapy.
- Estradiol, if you have breast tenderness or swelling.
Why are labs required before treatment?
Labs protect you in three ways. They confirm that low testosterone is actually the cause of your symptoms, so you don’t start a long-term medication for the wrong problem. They point to the cause, which decides which treatment can work. And they give a baseline for safety monitoring once treatment begins.
Testosterone is also a Schedule III controlled substance, so responsible prescribing requires documented low levels, a provider visit and ongoing follow-up. Be cautious of anyone offering testosterone without labs.
What’s the difference between TRT and enclomiphene?
The two main options work in opposite directions. Our TRT vs. enclomiphene comparison goes into detail, but in short:
| TRT (testosterone) | Enclomiphene | |
|---|---|---|
| How it works | Replaces testosterone from outside the body | Signals your body to make more of its own |
| Effect on sperm production | Can lower it | Maintained in clinical studies |
| Works if the testes don’t respond | Yes | No, it needs working testes |
| FDA status | Testosterone cypionate injection is FDA-approved | Not FDA-approved; compounded |
| Form at Surna | Weekly injection or daily cream | Daily capsule |
| Surna starting price | $99/mo | $119/mo |
Why does fertility matter so much here?
When you take testosterone, your brain senses enough of it and turns down the signals (LH and FSH) that tell the testes to make both testosterone and sperm. Sperm production can fall, sometimes very low. It often recovers after stopping, but recovery can take time. The AUA advises that testosterone therapy should not be prescribed to men who are currently trying to conceive.
Enclomiphene works upstream. It blocks estrogen’s feedback in the brain so the pituitary sends a stronger signal to the testes. In randomized phase III studies of overweight men with secondary hypogonadism, enclomiphene raised testosterone, LH and FSH and kept sperm concentrations in the normal range, while testosterone gel lowered LH, FSH and sperm counts. Enclomiphene only works when the testes can respond, which is one more reason labs come first.
What does monitoring look like on treatment?
Both options require follow-up labs. On TRT, monitoring usually includes testosterone levels, hematocrit and PSA. On enclomiphene, it includes testosterone and estrogen levels. Stop enclomiphene and contact your provider if you notice vision changes.
On heart safety, the TRAVERSE trial of men with or at high risk of heart disease found testosterone gel did not increase major cardiac events compared with placebo, over a mean follow-up of about 33 months. It did see more atrial fibrillation, acute kidney injury and blood clots in the lungs, so these are worth discussing with your provider.
Testosterone is usually not a fit for men with prostate or breast cancer, a high red blood cell count, untreated severe sleep apnea, or plans to conceive soon. Your provider makes the final call.
How do you get tested?
At Surna, both testosterone and enclomiphene start with labs and a video visit. A licensed provider reviews your results and prescribes only if treatment is appropriate. Individual results vary. You can explore all hormone health treatments or start your assessment.
Sources
- Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol. 2018;200:423-432. auanet.org
- Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. doi.org
- Kim ED, McCullough A, Kaminetsky J. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone. BJU Int. 2016;117:677-685. doi.org
- Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE). N Engl J Med. 2023;389:107-117. nejm.org
- DailyMed. Testosterone cypionate injection prescribing information. dailymed.nlm.nih.gov
This article is general information, not medical advice. Compounded medications, including enclomiphene and testosterone cream, are prepared by state-licensed pharmacies and are not FDA-approved.