Low testosterone symptoms are real, but they are also vague. Low mood, poor sleep, tiredness and a flat sex drive can come from low testosterone. [1] The NHS says that in many cases they are "nothing to do with hormones". [1]

Only a testosterone blood test, read with your symptoms, can settle it. [2] This article covers what to look for, what else is often behind the same symptoms and how a GP assesses testosterone. It ends with the habits that support your health as a whole.

What are the symptoms of low testosterone in men?

The NHS describes a cluster that appears in some men in their late 40s to early 50s. [1] It names depression, loss of sex drive and erectile dysfunction, with other physical and emotional symptoms. [1] It lists six more that are common in men of this age: [1]

  • mood swings and irritability
  • loss of muscle mass and reduced ability to exercise
  • fat redistribution, such as developing a large belly or enlarged breast tissue (gynaecomastia)
  • a general lack of enthusiasm or energy
  • difficulty sleeping or increased tiredness
  • poor concentration and short-term memory

Not all of these point to testosterone equally. The British Society for Sexual Medicine (BSSM) says three sexual symptoms are the most suggestive, particularly together. [2] They are low sexual desire, fewer morning erections and erectile dysfunction. [2]

Fatigue, sleep disturbance, loss of strength, low energy and depressed mood are less specific. [2] The more of these signs a man has, the greater the probability of a genuine deficiency. [2]

Why do symptoms alone not confirm low testosterone?

Because the same symptoms are also found in men with normal testosterone. The BSSM says many of them are "multifactorial in origin", linked to lifestyle, psychological factors and normal ageing. [2]

The NHS calls the "male menopause" an unhelpful term. [1] It says the label is misleading because it suggests a sudden drop in testosterone in middle age, like the female menopause. [1] The NHS says that is not true. [1]

Testosterone falls steadily by about 1% a year from around age 30 to 40, which the NHS says is unlikely to cause problems in itself. [1]

A true deficiency that develops later in life is called late-onset hypogonadism, where the testes produce few or no hormones. [1] The NHS calls it "an uncommon and specific medical condition that's not a normal part of ageing". [1] It is seen particularly in men with obesity or type 2 diabetes. [1]

How common is a true deficiency?

Rarer than the symptom list suggests. In the European Male Ageing Study of men aged 40 to 79, 2.1% met the research definition. [2] [3] That definition is at least three sexual symptoms plus low total testosterone and low free testosterone, the unbound portion the body can use. [2]

The rate rose from 0.1% in men in their 40s to 5.1% in their 70s. [2] Many men with these symptoms therefore do not have low testosterone. [1] The BSSM notes that about three quarters of men keep normal levels into old age. [2]

What else could be causing these symptoms?

Several common, treatable conditions produce the same picture, and guidance says to test for them alongside testosterone rather than after it. [4] The table shows where each symptom also turns up in guidance from the NHS and NICE, the body that writes NHS clinical guidance. [5] Sleep apnoea, where breathing stops and starts during sleep, appears in several rows.

Symptoms men attribute to testosterone, and their other common causes
SymptomAlso common in
Tiredness and low energySleep apnoea, depression, an underactive thyroid, diabetes, alcohol and some medicines [5] [6]
Low mood and irritabilityDepression, stress, sleep apnoea, an underactive thyroid and heavy drinking [7] [8] [9] [6]
Low sex driveStress, anxiety or depression, relationship problems, alcohol, some medicines, heart disease, diabetes and an underactive thyroid [10]
Erectile difficultiesStress, tiredness or alcohol; if frequent, high blood pressure or cholesterol, diabetes, depression or anxiety, hormone problems and some medicines [11]
Poor concentration or memorySleep apnoea, depression, stress and an underactive thyroid [12] [13] [14] [9]

Could it be sleep apnoea?

Obstructive sleep apnoea is when your breathing stops and starts while you sleep. At night the NHS lists gasping, snorting or choking noises, waking a lot and loud snoring. [8] By day it lists feeling very tired, finding it hard to concentrate and mood swings. [8]

NICE CKS, the NICE summaries written for GPs, estimates that up to 4% of middle-aged men in the UK have obstructive sleep apnoea syndrome. [12] Underdiagnosis may reach 85%, and it is about twice as common in men as in women. [12] NICE also lists sexual dysfunction among its symptoms. [12]

It is one of the conditions the BSSM links with a higher rate of testosterone deficiency. [2] It can be hard to tell you have it, so the NHS suggests asking someone to watch you sleep. [8] Our guide to sleep apnoea and weight gain covers the overlap.

Could it be stress or low mood?

Stress can cause sexual problems, difficulty concentrating, forgetfulness, irritability and sleeping too much or too little. [14] Depression brings continuous low mood, lack of energy, low sex drive and disturbed sleep. [7] NICE CKS notes depression may show up as vague symptoms rather than low mood. [13]

In a systematic review of 26 primary care studies, depression was the most common cause of tiredness, found in 18.5% of people. [5] The NHS says to see a GP if symptoms of depression last most of the day, every day, for more than 2 weeks. [7]

Could it be an underactive thyroid?

Feeling extremely tired, feeling cold, putting on weight, difficulty concentrating and low mood are all common symptoms of an underactive thyroid. [9] They develop slowly, can be mild and are also caused by other conditions, so the NHS says to get them checked. [9]

A blood test checks TSH, the hormone that tells the thyroid how hard to work. [9] Our TSH blood test guide explains what the result means.

Could it be alcohol?

The NHS says most men occasionally fail to get or keep an erection, usually because of stress, tiredness or drinking too much alcohol. [11] Drinking too much is also on its list of causes of a low sex drive. [10]

Heavy drinking is strongly linked to depression, and alcohol can disrupt sleep patterns and stop deep sleep. [6] The UK guideline is no more than 14 units a week, spread over 3 or more days, with several drink-free days. [15]

On testosterone itself, pooled observational studies found no significant overall difference between drinkers and non-drinkers. [16] The changes appear in men with alcohol use disorder. [16]

Could it be a medicine or another condition?

Erectile dysfunction can be a side effect of some medicines. [11] Medicines for high blood pressure and for depression are among the causes of a low sex drive. [10] NICE CKS lists several medicine groups among the causes of tiredness. [5]

The BSSM says some medicines can suppress testosterone, including some long-term painkillers and some used for epilepsy, mental health conditions and inflammation. [2] If you take regular medication, mention it to your GP rather than stopping it yourself.

Long-term conditions matter too. The NHS lists heart disease, diabetes and an underactive thyroid among conditions that can affect sex drive. [10] High blood pressure, high cholesterol and diabetes are among its causes of frequent erectile dysfunction. [11]

Could it be your weight?

This is the lifestyle factor with the clearest measured link to testosterone. The NHS says late-onset hypogonadism develops particularly in men with obesity or type 2 diabetes. [1]

In a pooled analysis of 24 studies in men with obesity, weight loss was associated with higher total testosterone. [17] The amount of weight lost was the best predictor of the rise. [17] In the European Male Ageing Study, weight loss was associated with a proportional rise in testosterone and weight gain with a proportional fall. [18]

The European Association of Urology says weight loss and lifestyle change should be the first approach for men with hypogonadism and excess weight. [19] It also says the rise after a low-calorie diet and physical activity is small, 1 to 2 nmol/L. [19]

Our article on low testosterone and weight gain explains the two-way cycle, and visceral fat in men covers why fat around the organs matters.

How is low testosterone assessed?

By symptoms and blood tests together. The BSSM says the diagnosis requires characteristic signs and symptoms plus a reduced blood testosterone. [2]

Testosterone follows a daily rhythm and is highest in the early morning. [2] So the sample is taken between 7 and 11 in the morning, ideally fasting. [2] Non-fasting levels can be up to 30% lower. [2]

A low or borderline result is repeated, so there are at least two measurements, preferably 4 weeks apart and not during an acute illness. [2]

If it stays low, two more hormones are checked: LH and FSH, from the pituitary gland in the brain. They show whether the cause is in the testes or the pituitary. [2] SHBG, a carrier protein, is checked when the total is borderline. [2]

A GP assessing erectile dysfunction arranges the same morning testosterone test. [4] Alongside it come HbA1c (average blood sugar over about 3 months), a lipid profile (cholesterol and blood fats) and a cardiovascular risk calculation. [4] Thyroid, liver and kidney tests may be added. [4]

HeMed's blood test does not include testosterone, SHBG, LH or FSH; your GP can arrange them. It does include TSH, HbA1c, three liver enzymes and five cholesterol markers.

Which lifestyle factors support your overall health?

Several habits have good evidence for general health. Weight is the one with the clearest measured link to testosterone, covered above. None is a treatment for a confirmed deficiency.

What about sleep and activity?

Sleep: most healthy adults need around 7 to 9 hours a night. [20] One week of 5-hour nights lowered daytime testosterone by 10 to 15% in a study of 10 young men. [21] A larger pooled analysis of 18 studies found no significant effect of short-term partial sleep loss. [22]

Activity: the UK Chief Medical Officers recommend 150 minutes of moderate activity a week and strength work on at least 2 days. [23] In 11 randomised trials of 421 insufficiently active men, exercise training had a negligible effect on resting testosterone. [24] Train for your heart, muscle and mood rather than your hormone level.

What about alcohol, stress and diet?

Alcohol: staying within 14 units a week is the NHS advice for men with erection problems. [11] The NHS says cutting down should help you feel more rested and may lift your mood. [6]

Stress: the NHS says exercise and relaxation can help, and so can talking to someone. [1] Samaritans, on 116 123, are there for everyone. [14]

Diet: the Eatwell Guide says to eat at least 5 portions of fruit and vegetables a day and choose wholegrain starchy foods. [25] Add beans, pulses, fish and other protein foods, with unsaturated oils in small amounts. [25]

No lifestyle change is guaranteed to raise your testosterone. The BSSM says studies suggest oral products marketed to "boost" testosterone do not raise levels above placebo (a dummy treatment). [2] If a blood test confirms a deficiency, treatment is a conversation with your GP or a specialist.

When should you see a GP?

The NHS says to see your GP if you are experiencing these symptoms. [1] They will ask about your work and personal life as well as your health. [1] Go sooner in these cases:

  • Erection problems that keep happening in an otherwise well man: NICE CKS says they "may be a marker of underlying coronary artery disease" (heart disease). [11] [4]
  • Low mood most of the day, every day, for more than 2 weeks. [7]
  • Breathing that stops and starts in your sleep, gasping or choking noises, or always feeling very tired in the day. [8]
  • Losing weight without trying, which NICE CKS treats as a red flag for further assessment. [5]

If you have thoughts of harming yourself, you do not have to struggle alone: call NHS 111 at any time, or Samaritans on 116 123. [26] If you have seriously harmed yourself or feel you are about to, call 999 or go straight to A&E. [26]

Go in with a short list: your symptoms and when they started, the medicines you take, and how much you drink and sleep. It makes the appointment more useful.

Where does HeMed fit in?

HeMed starts with a blood test. You start with a needle-free test of 10 markers across your heart, liver, blood sugar and thyroid. HeMed's test does not measure testosterone; if low testosterone is the question, your GP can arrange a morning blood test.

The 10 markers include TSH (thyroid), HbA1c (blood sugar), three liver enzymes and five cholesterol markers. Fasting tests and hormone panels are not included; those are arranged through your GP.

A clinician reviews your blood test first. A retest every 6 months shows what's actually changing. See what a men's health blood test checks for.

HeMed does not diagnose or treat the conditions described above.

Frequently asked questions

Can you have low testosterone without symptoms?

A low reading without symptoms is possible, but guidance does not count it as a deficiency. The diagnosis needs persistent symptoms and a confirmed low level. [2] The BSSM also notes a lack of evidence for benefit from treating men without symptoms. [2]

Equally, many men with these symptoms have normal testosterone, which is why the blood test is read alongside how you feel, not instead of it. [1] [2]

What time of day should testosterone be tested?

In the morning, between 7 and 11, ideally fasting, because levels peak early and non-fasting levels can be up to 30% lower. [2] A low or borderline result is repeated on another day before any conclusion is drawn. [2]

Is the male menopause a real condition?

Not as the name suggests. The NHS calls the term unhelpful and misleading, because it suggests a sudden drop in testosterone in middle age like the female menopause. [1] Testosterone falls slowly, by about 1% a year from around 30 to 40, and in many cases the symptoms are nothing to do with hormones. [1]

Can lifestyle changes treat low testosterone?

No habit treats a confirmed deficiency, though weight loss is associated with higher testosterone in men with obesity. [17] The European Association of Urology puts the rise after diet and activity at a small 1 to 2 nmol/L. [19]

Exercise training had a negligible effect on resting testosterone in pooled trials of insufficiently active men. [24]

Can I get testosterone measured through HeMed?

No. The HeMed blood test measures 10 markers across four systems. Testosterone, SHBG, LH and FSH are not among them.

For a testosterone test, speak to your GP.

When should I see a GP about these symptoms?

If they are persistent or affecting daily life. The NHS thresholds are low mood for more than 2 weeks, erection problems that keep happening, and any main symptom of sleep apnoea. [7] [11] [8]

What happens if a deficiency is confirmed?

Your GP may refer you to an endocrinologist, a specialist in hormone problems. [1] If the diagnosis is confirmed, the specialist may offer hormone treatment under specialist care. [1] For men with excess weight, guidance puts weight loss and lifestyle change first. [19]

HeMed provides clinician-led weight management. We do not diagnose or treat low testosterone, depression, sleep apnoea or thyroid disease. This page is general health information, not medical advice. If you are worried about symptoms, speak to your GP, or use NHS 111.

Next step: see what the HeMed blood test measures.

Sources (26)
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  2. Hackett G, Kirby M, Rees RW and colleagues. "The British Society for Sexual Medicine guidelines on male adult testosterone deficiency, with statements for practice." World Journal of Men's Health 2023;41(3):508 to 537: EMAS "overall prevalence of 2.1% in men aged 40-79 years and rates of 0.1% in 40-49 year olds, 0.6% in 50-59 year olds, 3.2% in 60-69 year olds and 5.1% in 70-79 year olds"; "75% of men maintained normal testosterone levels into old age"; the diagnosis "requires the presence of characteristic signs and symptoms (Level 2, Grade A), PLUS reduced serum concentrations of TT or FT"; sexual symptoms "particularly suggestive of TD when associated with each other (LoE 1, Grade A)"; "Less-specific symptoms such as fatigue, sleep disturbance, loss of physical strength, reduced energy and motivation, and depressed mood are often present (LoE 1, Grade B)"; "Many signs and symptoms of TD are multifactorial in origin"; "The more signs/symptoms a man has, the greater the probability that he has genuine TD"; "Serum testosterone should be measured between 7 am and 11 am (LoE 2a, Grade A), on at least 2 occasions with a reliable method (LoE 1, Grade A), preferably 4 weeks apart and, if possible, not during an acute illness"; "Fasting levels were found to be up to 30% higher than non-fasting levels in healthy volunteers" and, in its recommendations table, "in normal life, non-fasting levels may be up to 30% lower"; LH to differentiate primary and secondary deficiency, SHBG when total testosterone is borderline; obstructive sleep apnoea among factors associated with an increased prevalence; "Certain medications may suppress testosterone levels"; "Restrict the diagnosis of TD to men with persistent symptoms suggesting TD and confirmed low testosterone"; "a lack of evidence for benefit of T Therapy in asymptomatic individuals"; oral "boosting" supplements "do not raise serum testosterone levels above placebo". doi.org/10.5534/wjmh.221027. Accessed 10 November 2026.
  3. Pye SR and colleagues, EMAS Study Group. "Late-onset hypogonadism and mortality in aging men." Journal of Clinical Endocrinology and Metabolism 2014;99(4):1357 to 1366 (2,599 community-dwelling men aged 40 to 79 in eight European countries; "Fifty-five men (2.1%) were identified as having LOH"). doi.org/10.1210/jc.2013-2052. Accessed 10 November 2026.
  4. NICE Clinical Knowledge Summaries, "Erectile dysfunction", last revised July 2026: for all men, arrange "Serum HbA1c or fasting blood glucose", "Serum lipid profile", a 10-year cardiovascular risk calculation and "A fasting serum total testosterone (taken between 9-11 am)", with thyroid, liver and renal function tests considered; "Erectile dysfunction in an otherwise asymptomatic man may be a marker of underlying coronary artery disease [Hackett, 2018]"; assessment "may provide an opportunity for early diagnosis and management of underlying condition(s) such as cardiovascular or endocrine disease". cks.nice.org.uk/topics/erectile-dysfunction. Accessed 10 November 2026.
  5. NICE Clinical Knowledge Summaries, "Tiredness/fatigue in adults", last revised June 2025: physical causes "include anaemia, diabetes mellitus, viral or post-viral infections, other infections, sleep disorders, or malignancy"; drug causes include antidepressants, antihistamines, antihypertensives, beta-blockers and opiates; psychosocial causes include "depression, anxiety, stress"; in "The systematic review of 26 studies investigating the differential diagnosis of tiredness in primary care", depression "was the most common cause (seen in 18.5% of people)"; common underlying causes include obstructive sleep apnoea and thyroid disease; "Significant unintentional weight loss (5% of body weight over 6-12 months)" is a red flag. cks.nice.org.uk/topics/tiredness-fatigue-in-adults. Accessed 10 November 2026.
  6. NHS, "Tips on cutting down on alcohol", page last reviewed 9 April 2026: "There's a strong link between heavy drinking and depression"; drinking "can disrupt your sleep patterns and stop you sleeping deeply"; immediate effects of cutting down include "being less tired during the day" and "feeling more energetic". nhs.uk/live-well/alcohol-advice/tips-on-cutting-down-alcohol. Accessed 10 November 2026.
  7. NHS, "Depression in adults: symptoms", page last reviewed 5 July 2023 (its stated next review date, 5 July 2026, had passed on the access date): psychological symptoms include "continuous low mood or sadness", "feeling irritable and intolerant of others" and "having no motivation or interest in things"; physical symptoms include "lack of energy", "low sex drive (loss of libido)" and "disturbed sleep"; "See a GP if you experience symptoms of depression for most of the day, every day, for more than 2 weeks." nhs.uk. Accessed 10 November 2026.
  8. NHS, "Sleep apnoea", page last reviewed 11 May 2026: "Sleep apnoea is when your breathing stops and starts while you sleep"; night-time symptoms "your breathing stopping and starting; making gasping, snorting or choking noises; waking up a lot; loud snoring"; by day "feel very tired; find it hard to concentrate; have mood swings; have a headache when you wake up"; "It may help to ask someone to stay with you while you sleep so they can check for the symptoms"; see a GP for the main symptoms; untreated, it can lead to "depression or mood changes". nhs.uk/conditions/sleep-apnoea. Accessed 10 November 2026.
  9. NHS, "Underactive thyroid (hypothyroidism)", page last reviewed 28 April 2025: common symptoms include "feeling extremely tired (fatigue)", "feeling cold more than usual", "putting on weight", "difficulty concentrating or thinking clearly" and "low mood or depression"; "Symptoms usually develop slowly"; "Some of the symptoms are common and can be caused by other conditions. But it's important to get them checked by a GP"; blood tests check thyroid-stimulating hormone (TSH) and thyroxine. nhs.uk/conditions/underactive-thyroid-hypothyroidism. Accessed 10 November 2026.
  10. NHS, "Low sex drive (loss of libido)", page last reviewed 26 May 2026: causes include "relationship problems", "stress, anxiety or depression", "taking certain medicines, such as medicine for high blood pressure or antidepressants" and "drinking too much alcohol"; "Some long-term conditions can also affect your sex drive, such as heart disease, diabetes, an underactive thyroid or cancer." nhs.uk/symptoms/loss-of-libido. Accessed 10 November 2026.
  11. NHS, "Erectile dysfunction (impotence)", page last reviewed 28 July 2023 (its stated next review date, 28 July 2026, had passed on the access date): "Most men occasionally fail to get or keep an erection. This is usually caused by stress, tiredness or drinking too much alcohol"; "It can also be a side effect of some medicines"; frequent erectile dysfunction "may be caused by a condition such as: high blood pressure or high cholesterol; diabetes; depression or anxiety; hormone problems"; "do not drink more than 14 units of alcohol a week"; see a GP if "erection problems keep happening". nhs.uk/conditions/erection-problems-erectile-dysfunction. Accessed 10 November 2026.
  12. NICE Clinical Knowledge Summaries, "Obstructive sleep apnoea syndrome", last revised November 2025: "Up to 4% of middle-aged men and 2% of middle-aged women in the UK are estimated to have OSAS [NICE, 2021]; although the true prevalence is likely higher as underdiagnosis may reach 85%"; "approximately twice as common in men as in women"; suspect it with "Excessive daytime sleepiness, tiredness, fatigue, or unrefreshing sleep", snoring or witnessed pauses, or "Cognitive dysfunction, memory impairment or impaired concentration"; NICE lists "sexual dysfunction" among the symptoms. cks.nice.org.uk/topics/obstructive-sleep-apnoea-syndrome. Accessed 10 November 2026.
  13. NICE Clinical Knowledge Summaries, "Depression: when should I suspect a diagnosis of depression?", last revised April 2025: "Be aware that a person with depression may present with non-specific symptoms rather than low mood"; associated symptoms include "Disturbed sleep", "Fatigue or loss of energy" and "Poor concentration or indecisiveness". cks.nice.org.uk/topics/depression. Accessed 10 November 2026.
  14. NHS, "Stress", page last reviewed 6 March 2026: physical symptoms include "sexual problems"; mental symptoms include "difficulty concentrating" and "being forgetful"; behaviour changes include "being irritable and snappy", "sleeping too much or too little" and "drinking or smoking more"; "you could also contact Samaritans by phone on 116 123 if you need someone to talk to". nhs.uk. Accessed 10 November 2026.
  15. NHS, "The risks of drinking too much", page last reviewed 10 September 2026: "men and women are advised not to drink more than 14 units a week on a regular basis"; "spread your drinking over 3 or more days if you regularly drink as much as 14 units a week"; "try to have several drink-free days each week"; "there's no safe drinking level". nhs.uk/live-well/alcohol-advice/the-risks-of-drinking-too-much. Accessed 10 November 2026.
  16. Moosazadeh M and colleagues. "Association of the effect of alcohol consumption on luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone hormones in men: a systematic review and meta-analysis." International Journal of Preventive Medicine 2024;15:75 (17 observational studies; standardised mean difference for testosterone in alcohol-exposed versus non-exposed groups 0.03, 95% CI -0.11 to 0.16, "showing no statistical significance"; "notable alterations observed in testosterone levels among individuals with alcohol use disorder"). doi.org/10.4103/ijpvm.ijpvm_81_24. Accessed 10 November 2026.
  17. Corona G, Rastrelli G, Monami M and colleagues. "Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis." European Journal of Endocrinology 2013;168(6):829 to 843 (24 studies; weight loss "associated with a significant (P<0.0001) increase" in total testosterone; "the degree of body weight loss is the best determinant of TT rise"). doi.org/10.1530/EJE-12-0955. Accessed 10 November 2026.
  18. Camacho EM and colleagues, EMAS Group. "Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study." European Journal of Endocrinology 2013;168(3):445 to 455 (2,736 men aged 40 to 79 followed for a mean 4.4 years; "Weight loss was associated with a proportional increase, and weight gain a proportional decrease, in testosterone and SHBG"). doi.org/10.1530/EJE-12-0890. Accessed 10 November 2026.
  19. European Association of Urology, "EAU Guidelines on Sexual and Reproductive Health", chapter "Male hypogonadism", 2026 edition: "weight loss and lifestyle changes should be the first approach for all men with hypogonadism that are overweight or obese"; "the increase in testosterone levels observed after a low-calorie diet and physical activity is small (1-2nmol)"; measure total testosterone in the morning and fasting, repeated on at least two occasions when low. uroweb.org/guidelines/sexual-and-reproductive-health. Accessed 10 November 2026.
  20. NHS, Every Mind Matters, "Sleep": "Most healthy adults need around 7 to 9 hours of sleep a night, although the exact amount can be different for each person." nhs.uk/every-mind-matters. Accessed 10 November 2026.
  21. Leproult R, Van Cauter E. "Effect of 1 week of sleep restriction on testosterone levels in young healthy men." JAMA 2011;305(21):2173 to 2174 (10 healthy men, mean age 24; after 8 nights of 5-hour bedtimes, daytime testosterone 16.5 against 18.4 nmol/L, "decreased by 10% to 15%"). doi.org/10.1001/jama.2011.710. Accessed 10 November 2026.
  22. Su L, Zhang SZ, Zhu J, Wu J, Jiao YZ. "Effect of partial and total sleep deprivation on serum testosterone in healthy males: a systematic review and meta-analysis." Sleep Medicine 2021;88:267 to 273 (18 studies, 252 men; "short-term partial sleep deprivation had no significant effect on male serum testosterone (SMD = -0.22; 95% CI: -0.5, 0.06; P = 0.13), while total sleep deprivation reduced the male testosterone levels"). doi.org/10.1016/j.sleep.2021.10.031. Accessed 10 November 2026.
  23. UK Chief Medical Officers, "Physical activity guidelines", 2019, page updated 10 July 2026: adults "should accumulate at least 150 minutes (2 and a half hours) of moderate intensity activity" a week and do muscle-strengthening activities "on at least 2 days a week, but any strengthening activity is better than none". gov.uk. Accessed 10 November 2026.
  24. Potter NJ, Tomkinson GR, Dufner TJ and colleagues. "Effects of exercise training on resting testosterone concentrations in insufficiently active men: a systematic review and meta-analysis." Journal of Strength and Conditioning Research 2021;35(12):3521 to 3528 (11 randomised trials, 421 men aged 19 to 75; "exercise training had a negligible effect on resting total testosterone concentration (mean SMD [95% CI]: 0.00 [-0.20 to 0.20])"; not affected by training mode, age or body mass). doi.org/10.1519/JSC.0000000000004146. Accessed 10 November 2026.
  25. NHS, "The Eatwell Guide", page last reviewed 29 November 2022 (its stated next review date, 29 November 2025, had passed on the access date): "Eat at least 5 portions of a variety of fruit and vegetables a day"; "Choose higher fibre or wholegrain varieties"; "Eat some beans, pulses, fish, eggs, meat and other protein foods"; "Choose unsaturated oils and spreads, and eat in small amounts". nhs.uk/live-well/eat-well. Accessed 10 November 2026.
  26. NHS, "Help for suicidal thoughts", page last reviewed 26 April 2024: "You do not have to struggle with difficult feelings alone"; "NHS 111. Call 111, 24 hours every day"; "Samaritans, for everyone. Call 116 123"; "If you have seriously harmed yourself, for example, by taking a drug overdose, or you feel that you may be about to harm yourself, call 999 for an ambulance or go straight to A&E." nhs.uk. Accessed 10 November 2026.

Numbered markers in the page text link to these entries. Statistics describe populations, not any one person’s results.

Published 10 November 2026.