Hormonal & Metabolic

Is low testosterone dangerous? Is taking testosterone dangerous?

Medically reviewed by Dr Martin Galy, Co-Founder & Director of Wellness & Longevity · Published 1 November 2026 · Last reviewed 1 November 2026

Quick answer: Low testosterone is not an emergency, but it can really matter for long-term health. Large studies link it with type 2 diabetes, weaker bones, anaemia and, at very low levels, a higher risk of death, and it is often a warning sign of other health problems. Taking testosterone under medical supervision did not increase heart attacks or strokes in the largest trial, but it has risks of its own, so it needs a confirmed diagnosis and regular monitoring.

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Our guide to the symptoms of low testosterone and when to get checked covers the first question. This article answers the next one many men ask: if my testosterone is low, does it matter for my health in the long run?

What are the long-term risks of low testosterone?

The British Society for Sexual Medicine (BSSM) 2023 guideline links low testosterone with several long-term health problems [1]:

Type 2 diabetes and metabolic health: multiple studies show a higher risk of developing type 2 diabetes [1]. In men aged 45 and over seen in primary care, those with testosterone deficiency were about twice as likely to have type 2 diabetes or obesity, and more likely to have high blood pressure [1].
Heart and circulation: erection problems and loss of morning erections are recognised early markers of heart disease risk [1]. At very low levels, testosterone is linked with a higher risk of dying from cardiovascular disease [2].
Bones: testosterone helps maintain bone density in men [3]. Significant deficiency is associated with a higher risk of osteoporosis [1].
Blood: significant deficiency is associated with chronic anaemia (a low red blood cell count) [1].
Muscle, strength and falls: loss of muscle and leg strength is strongly related to frailty and falls in older men [1].
Other conditions: low testosterone is linked with worse outcomes in chronic kidney disease [1].

Does low testosterone shorten life?

If levels are very low, there is a clear link. A 2024 analysis in the Annals of Internal Medicine pooled individual data from 11 studies of 24,109 men followed for at least five years [2]. Men with a total testosterone below 7.4 nmol/L had a higher risk of death from any cause, and men below 5.3 nmol/L had a higher risk of death from cardiovascular disease [2].

Those levels are well below the 12 nmol/L that UK guidelines usually use to define testosterone deficiency [1]. The study was observational, so it shows a link, not that low testosterone itself causes earlier death [2].

How low is too low?

Different problems appear at different levels. In one study of 434 men aged 50 to 86, reduced energy appeared at around 15 nmol/L, obesity at around 12, diabetes and low mood at around 10, and loss of erections at around 8 [1].

Morning total testosterone	What the evidence shows
Below 12 nmol/L on two tests, with symptoms	The usual UK threshold for testosterone deficiency [1]
Below 7.4 nmol/L	Linked with a higher risk of death from any cause [2]
Below 5.3 nmol/L	Linked with a higher risk of death from cardiovascular disease [2]

One result is never enough. Testosterone varies through the day and after meals, so guidelines recommend two fasting morning tests before drawing conclusions [1][4].

Is low testosterone a cause or a warning sign?

Often both. Obesity, type 2 diabetes, poor sleep and long-term illness can all lower testosterone, and low testosterone may in turn make body fat and blood sugar harder to control. The BSSM notes a consistent link between low testosterone and mortality even after allowing for other illnesses, "without proving causation" [1].

This is why a low result should prompt a wider look at blood sugar, cholesterol, blood pressure, weight, sleep and bone health. At 23MD this can sit alongside our metabolic health assessment.

Does treating low testosterone reduce these risks?

That is not yet proven. In men with confirmed deficiency, treatment can improve symptoms such as low sex drive, and some studies show improved bone density [1][3]. But there is no evidence that treatment prevents fractures [3], and it has not been shown to prevent heart attacks or early death.

Guidelines recommend diagnosing deficiency only when symptoms are present and levels are consistently low, and discussing benefits, risks and monitoring before any treatment [1][4]. Treatment is a decision for each man and his doctor, not a default.

Is taking testosterone dangerous?

For men with confirmed deficiency, testosterone treatment has now been tested in a large trial, and the results on the heart are reassuringly safe. The risks are the reason treatment needs careful monitoring.

Prostate: over two to three years, prostate cancer was diagnosed in fewer than 1% of men in each group, with no significant difference, and urinary symptoms were similar [7].
Heart and circulation: the TRAVERSE trial gave 5,204 men aged 45 to 80, all with low testosterone and existing heart disease or a high cardiovascular risk, either testosterone gel or a placebo gel. Over about three years, heart attacks, strokes and cardiovascular deaths occurred in 7.0% of the testosterone group and 7.3% of the placebo group, so there was no increase [5]. All the men in this trial used a daily testosterone gel on the skin; the results may not apply to injections or other forms of treatment.
Blood: testosterone can raise the red blood cell count. Short-acting injections tend to raise it most and skin patches least [9]. A haematocrit above 0.50 is a reason not to start treatment, and it should always be checked during treatment [8].
Fertility: A wish to preserve fertility is a reason not to start testosterone [8].

This evidence comes from supervised treatment at standard doses in men with confirmed deficiency. It does not apply to testosterone taken without a diagnosis or bought without a prescription. Guidelines recommend checking blood count and PSA before treatment and monitoring them afterwards [1][8]; we explain what that involves in BHRT, examined: who it is for and who it is not.

When should I see a doctor?

See a doctor if you have symptoms that could be linked to low testosterone, such as low sex drive, erection problems or loss of morning erections. The BSSM also recommends testing all men with type 2 diabetes, a BMI over 30 or a waist over 102 cm, chronic kidney disease or long-term opioid use, and men with osteoporosis or anaemia [1]. Read more about how we assess low testosterone symptoms at 23MD.

The 23MD view

"A low testosterone can be associated with other conditions. We look at it alongside blood sugar control, cholesterol, blood pressure, weight, sleep and bone health, because in many men they move together. Our aim is to understand why levels are low and how to improve outcomes for your long-term health." — Dr Martin Galy

You can also read about our wider wellness and longevity care.

Who this is for, and who it isn't for

For men who have had a low testosterone result and want to understand what it means for their long-term health.
For men with type 2 diabetes, a larger waist, low bone density or anaemia who want a joined-up check.
Not for anyone with chest pain, sudden breathlessness or thoughts of self-harm: contact emergency services.
Not for men looking for a prescription without an assessment.
Not for men who want to preserve their fertility.

Frequently asked questions

Can low testosterone cause heart problems?

Very low testosterone is linked with a higher risk of dying from cardiovascular disease, but studies cannot show that it is the cause [2]. Erection problems can be an early warning sign of heart disease and are worth raising with a doctor [1].

Can low testosterone cause diabetes?

Low testosterone is linked with a higher risk of developing type 2 diabetes [1]. The link works both ways: excess weight and diabetes can also lower testosterone.

Does low testosterone cause osteoporosis?

Testosterone helps maintain bone density, and significant deficiency is associated with osteoporosis [1][3]. Men with osteoporosis should have their testosterone checked [1].

What testosterone level is dangerous?

A large 2024 analysis linked levels below 7.4 nmol/L with a higher risk of death from any cause, and below 5.3 nmol/L with a higher risk of cardiovascular death [2]. Any result should be confirmed with a repeat morning test and interpreted by a doctor [1][4].

Want to get your questions in order before you see a doctor? Our BHRT Expert explains common hormone symptoms and helps you prepare questions for a consultation. It gives general information only: it doesn't diagnose and doesn't replace an assessment with a doctor.

Talk to a 23MD doctor

Suitability and results vary, and your doctor will discuss the benefits and risks of any option with you. Book a men's health consultation with Dr Galy and our team.