Low Testosterone: Symptoms, Blood Tests and When to See a GP

Low testosterone in men can cause a low sex drive, erection problems, tiredness, low mood and loss of muscle. It is confirmed with two morning blood tests, fasting, on different days. It is often linked to obesity, type 2 diabetes, sleep apnoea or some medicines. In Spain it is called testosterona baja or hipogonadismo. This guide is by Dr. Pedro Yelamo Vera, a GP licensed in Spain (Colegiado No. 484814280).

What is low testosterone?

Testosterone is the main male sex hormone. It is made mostly in the testicles, on signals from the pituitary gland in the brain. When the body makes less than it needs and this causes symptoms, doctors call it hypogonadism. Testosterone falls slowly with age, by about 1% a year from the age of 30 or 40. The NHS says this alone rarely causes problems.

What are the symptoms of low testosterone?

• Less interest in sex and fewer morning erections.
• Erection problems.
• Tiredness and low energy.
• Low mood, irritability or trouble concentrating.
• Loss of muscle and more fat around the tummy.
• Less body hair, or breast growth.
• Weaker bones and, sometimes, hot flushes.
• Fertility problems.

Many of these symptoms also come from stress, depression, poor sleep or alcohol. So symptoms are not enough on their own: you need a blood test.

How is testosterone tested?

With a blood test for total testosterone, taken in the morning, ideally between 7 and 11, while fasting, as levels are highest early in the day. If it is low, it is repeated on another day. The doctor often also checks LH, FSH and prolactin. These show if the problem is in the testicles or the pituitary gland. Sometimes SHBG is added to work out free testosterone. Each lab has its own normal range. In Spain, ask for testosterona total in a análisis en ayunas.

What causes low testosterone?

• Obesity and type 2 diabetes: among the most common causes in adults.
• Untreated sleep apnoea.
• Medicines and drugs: opioids, long-term steroids, and anabolic steroids, which switch off the body's own supply.
• Heavy drinking.
• Testicle problems: injury, mumps, cancer treatment or Klinefelter syndrome.
• Pituitary problems, such as a benign growth or too much prolactin.
• Long-term liver or kidney disease, or iron overload (haemochromatosis).

How can I raise testosterone naturally?

If lifestyle is the cause, these changes can help:

• lose weight if you are overweight;
• get enough sleep, and get sleep apnoea treated;
• exercise regularly, including strength training;
• drink less alcohol and stop smoking;
• keep diabetes under control.

Supplements sold as "testosterone boosters" have not been shown to work, and some contain hidden ingredients. Ask a doctor before you take them.

When is testosterone treatment used?

Only when there are symptoms and two tests confirm the deficiency. An endocrinologist or urologist assesses it and looks for the cause first. Treatment needs a prescription and regular blood checks, because it can raise your haematocrit and affects the prostate. Testosterone from outside the body also stops sperm production, so it is not suitable if you want children. It is not for building muscle or boosting performance. Used that way, it harms the heart, liver and fertility.

What about testosterone in women?

Women also make testosterone, in much smaller amounts, in the ovaries and adrenal glands. Too much can cause acne, facial or body hair and irregular periods. The most common cause is polycystic ovary syndrome (PCOS). Low testosterone in women is not usually tested. If your sex drive drops after the menopause, talk to your doctor.

When to see a doctor

• You have several of these symptoms for weeks.
• You have ongoing erection problems or low sex drive.
• You notice breast growth or tenderness.
• You and your partner have not conceived after a year of trying.
• You use, or have used, anabolic steroids.

When to go to A&E or call 112

Go to A&E for sudden, severe pain in a testicle. If you use testosterone or anabolic steroids and get chest pain, shortness of breath, a swollen and painful leg, or sudden weakness on one side of the body, call 112.

Frequently asked questions about low testosterone

Getting a medical assessment

If you think you may have low testosterone and want advice, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain. You can also read about erectile dysfunction and blood test reviews. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.