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Erectile dysfunction
Tackle low testosterone
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All content on this page has been medically reviewed by: Hassan Thwaini, Clinical Pharmacist and Copywriter, Master of Pharmacy (MPharm) on 7 March, 2026. GPhC Registration: 2221320View profile
TESTOSTERONE TESTING
Get your diagnosis
We recommend our venous blood test, as this is the gold-standard method for accurately diagnosing testosterone deficiency and includes a doctor consultation with free confirmatory testing if your levels are low. If you’re not ready for a full diagnostic pathway, our simple at-home blood test offers a convenient initial indication of your testosterone levels.
What is low testosterone?
Testosterone is the hormone that plays a role in muscle strength, energy, mood, bone density, and sexual health. Clinically low testosterone is diagnosed when blood levels fall below the healthy range on repeated testing, alongside symptoms.
When levels drop, it can affect body composition, confidence, motivation, and long-term health. Symptoms matter because they signal when your body isn’t functioning as it should, and deserve proper medical attention.
SYMPTOMS
The signs of low testosterone
If these symptoms are holding you back, Numan can help.1 If you’ve already been diagnosed with low testosterone, email us at [email protected] and our clinical team will help guide you towards your next steps.
Decreased libido
Fatigue
Poor sleep
Mood changes
Difficulty concentrating
Loss of muscle mass
Increased body fat
Reduced hair growth
Causes
Causes of low testosterone
Low testosterone rarely has a single cause. For many men, it’s the result of overlapping factors:2
Age-related decline
Testosterone levels gradually decline with age.
Brain-to-testes hormone signalling becomes less efficient over time.
Testes may start to 'fail' as men grow older.
Changes in sleep, activity, and body composition can accelerate the drop.
Medical conditions
Excess body fat can disrupt the hormone signals needed for testosterone production.
Type 2 diabetes is closely linked to lower testosterone and impaired hormone balance.
Pituitary or hypothalamus disorders can reduce the signals that stimulate testosterone production.
Some medications may reduce T levels.
Lifestyle factors
Chronic stress can lower testosterone by disrupting hormone balance.
Testosterone is produced during deep sleep, so poor sleep directly reduces levels.
Excess alcohol, smoking, and recreational drug use can impair testosterone production.
Poor diet can limit the nutrients needed for hormone production.
Low physical activity reduces the body’s natural testosterone stimulation.
Shining the spotlight
Symptoms of low testosterone creep in gradually, but because they build slowly, they’re often swept under the carpet, leaving many men undiagnosed and unsupported.
At Numan, we don’t overlook it. We investigate properly, with thorough testing, doctor consultations, and a clear pathway to treatment.
25%
of men under 40 may experience signs of low testosterone, rising to roughly 40% in those over 45.3
33%
of erectile dysfunction cases may be linked to low testosterone.4
90%
of men with low testosterone go undiagnosed or misdiagnosed with conditions like depression.5
Digital clinic
Benefits of the Numan TRT Programme
Here’s what to expect from our online TRT programme.
Clinician-led treatment
Tailored treatment plans, designed by our clinicians to support your health journey.
Ongoing clinical care
Clinicians will help you manage potential side effects, make dosage adjustments, provide follow-up blood tests, and answer any questions you might have throughout the programme.
Doorstep delivery
Regardless of your treatment, your package will be delivered in a discreet box, right to your doorstep.
Results
What results to expect when you start TRT
Clinical studies have shown that as testosterone levels increase, some men report gradual improvements in areas such as energy, mood, and sexual wellbeing over time. Changes don’t happen overnight, and everyone responds differently, but treatment is designed to support steady, clinically-monitored progress.6
Month 1-3
Higher libido
Stronger erections
Improved mood and energy
Month 3-6
Higher strength and endurance
Fat loss
Motivation and mental clarity
Month 6 onwards
Faster recovery
Ongoing reduction in visceral fat
Bone strength
Already diagnosed with low testosterone?
If you're currently on TRT or have had a recent low testosterone blood test, email us at [email protected] and our clinical team will help guide you towards your next steps.
UK DOCTORS AND CLINICIANS
Your expert team
Specialists in medicine, nutrition, performance, and diagnostics.
Dr Tom Anderson
Clinical Product Lead
MBBS MRCGP
Abby Watts
Senior Nurse Prescriber
BSc Adult Nursing, IP
FAQS
Your questions answered
Low testosterone, often referred to as “Low T” or hypogonadism, is a medical condition in which the body doesn’t produce enough testosterone, the hormone for maintaining male physical and mental health.
Clinically low testosterone refers to a specific range of testosterone levels in the blood, which is considered below the normal threshold for a given age.5
You can read more here.
Testosterone deficiency can be caused by natural age-related decline, medical conditions such as obesity and type 2 diabetes, disorders affecting the testes or pituitary gland, and lifestyle factors like chronic stress, poor sleep, excess alcohol, and low physical activity. Often, it’s not one single cause but a combination of factors that gradually disrupt the body’s hormone signalling over time.2
Low testosterone is diagnosed through two early-morning venous blood tests to confirm consistently low levels of total testosterone and, where relevant, free testosterone. A diagnosis isn’t made on blood results alone; symptoms such as low libido, fatigue, reduced muscle mass, or mood changes must also be present. Both biochemical evidence and clinical symptoms are required to confirm testosterone deficiency properly.1
Yes, lifestyle changes can improve testosterone levels, particularly when deficiency is linked to weight gain, poor sleep, stress, or low physical activity.
Losing excess body fat, building muscle through resistance training, improving sleep quality, reducing alcohol intake, and managing stress can all support healthier hormone production. While lifestyle changes may not fully correct clinically low testosterone in every case, they are often the first and most important step.7
Two blood tests are required to ensure an accurate diagnosis of low testosterone. The initial test provides a preliminary assessment. Since testosterone levels can naturally fluctuate due to various factors, a second blood test confirms these results.1,5
This two-step process minimises the risk of false positives and provides a solid basis for any necessary treatment.
You can read more here.
A Venous Blood Test (VBT) is a clinical blood test taken from a vein, typically from the arm. It’s carried out by a trained professional, either in a clinic or at home by a mobile phlebotomist. This test provides a highly accurate and detailed analysis, making it suitable for medical diagnosis.
Knowledge
Testosterone: what you need to know
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References
*Low testosterone levels must be confirmed on the initial VBT to get a free doctor consultation. Normal results do not warrant further clinical intervention.
1 Morales A, Bebb RA, Manjoo P, Assimakopoulos P, Axler J, Collier C, et al. Diagnosis and management of testosterone deficiency syndrome in men: clinical practice guideline. CMAJ [Internet]. 2015;187(18):1369–77.
2 Sizar O, Leslie SW, Schwartz J. Male hypogonadism. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025.
3 Andre B. Araujo, Gretchen R. Esche, et al. Prevalence of Symptomatic Androgen Deficiency in Men, The Journal of Clinical Endocrinology & Metabolism, Volume 92, Issue 11, 1 November 2007, Pages 4241–4247
4 Rabijewski M, Papierska L, Kozakowski J, Zgliczyński W. The high prevalence of testosterone deficiency in population of Polish men over 65 years with erectile dysfunctions. Aging Male. 2012;15(4):258–62.
5 Layton JB, Li D, Meier CR, Sharpless JL, Stürmer T, Jick SS, et al. Testosterone lab testing and initiation in the United Kingdom and the United States, 2000 to 2011. J Clin Endocrinol Metab . 2014;99(3):835–42
6 Morley J. The benefits and risks of testosterone replacement therapy: a review. Ther Clin Risk Manag. 2009;427.
7 Kumagai H, Zempo-Miyaki A, Yoshikawa T, Tsujimoto T, Tanaka K, Maeda S. Lifestyle modification increases serum testosterone level and decrease central blood pressure in overweight and obese men. Endocr J. 2015;62(5):423–30.
Reclaim Your Vitality
Experiencing decreased libido, fatigue, or increased body fat? You might have low testosterone. Check if low-T is affecting you today.
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