Low Testosterone and Type 2 Diabetes: The Two-Way Relationship

The relationship between type 2 diabetes and low testosterone is one of the more clinically important interactions in men's health. Each makes the other more likely; each worsens the other if untreated. In Singapore, where rates of type 2 diabetes in men are high, understanding the link matters. This guide covers the mechanism, when to investigate, and what the evidence supports doing.

For broader context, see our complete guide to low testosterone.

The connection in plain English

Several large studies have shown that men with type 2 diabetes have higher rates of low testosterone than men without diabetes — by some estimates, 30–50% of men with type 2 diabetes have low testosterone. The relationship is bidirectional: low testosterone makes type 2 diabetes more likely, and type 2 diabetes makes low testosterone more likely.

How the loop works

Type 2 diabetes → low testosterone: Insulin resistance and the inflammation associated with it suppress the hypothalamic-pituitary-testicular axis. Obesity, which often accompanies type 2 diabetes, increases aromatase activity (converting testosterone to oestrogen). Untreated sleep apnoea, common in this population, further suppresses testosterone.

Low testosterone → worse glycaemic control: Testosterone supports insulin sensitivity and muscle mass. As testosterone drops, insulin resistance often worsens, body composition shifts toward more fat and less muscle, and metabolic risk compounds.

The result is a self-reinforcing pattern that's harder to break with diabetes management alone or hormonal management alone.

When to suspect low testosterone if you have diabetes

A testosterone test is reasonable if you have type 2 diabetes and:

• Persistent fatigue not explained by glycaemic control
• Reduced libido or erectile difficulties
• Difficulty losing weight despite diet and exercise effort
• Loss of muscle mass or strength
• Low mood or motivation
• Sleep issues including suspected sleep apnoea

Some clinical guidelines now recommend screening for low testosterone in men with type 2 diabetes who have any of these symptoms.

What the evidence supports

For men with both type 2 diabetes and confirmed hypogonadism, several randomised trials have studied the effects of TRT. Findings include:

• Modest improvements in insulin sensitivity
• Reductions in visceral fat and HbA1c in some studies
• Improvements in libido, energy, and sexual function
• No clear evidence that TRT alone reverses type 2 diabetes

TRT is not a treatment for type 2 diabetes; it's a treatment for confirmed hypogonadism that may improve some metabolic markers along the way. Diabetes management remains its own thing.

A reasonable approach

For a man with type 2 diabetes who suspects low testosterone, a reasonable sequence:

• Optimise diabetes management first (medication adjustment, weight, sleep, exercise)
• Screen for sleep apnoea if any signs present
• Test testosterone if symptoms suggest
• Address reversible factors before considering TRT
• Discuss TRT with a doctor if hypogonadism is confirmed and significantly affecting quality of life

Frequently asked questions

Will TRT cure my diabetes?

No. TRT can improve some metabolic markers in men with both conditions, but does not cure type 2 diabetes. Diabetes management remains essential.

Should every man with diabetes get tested for low T?

Not necessarily — but men with type 2 diabetes who have any of the typical low-T symptoms should be tested. Some guidelines support broader screening in this population.

Can losing weight improve my testosterone?

Yes — weight loss in overweight men with both conditions consistently improves testosterone and improves diabetes control. The effects compound.

Speak to a doctor on Noah

If you have type 2 diabetes and suspect low testosterone is part of your picture, you can book a confidential consultation with a Singapore-licensed doctor on Noah.