Thomas is 38. He's in good shape, works hard, and has a relationship he values. But over the past year and a half, he's noticed something: his desire for sex has become milder. Not absent, but softer. Less initiative than before. He wonders whether this is "normal," or whether something is wrong.
Chances are this story sounds familiar. Not just for Thomas, but for a large proportion of men in their thirties, forties, and fifties. And the question most of them don't ask their doctor, but do google at midnight: is this my testosterone?
The answer: maybe. But it's more complicated than that.
What Is Testosterone and What Does It Do?
Testosterone is an androgen, a sex hormone, produced primarily in the Leydig cells of the testes in men, and to a lesser extent in the adrenal glands. It regulates a broad range of functions: muscle mass, bone density, body hair, voice depth, red blood cell production, and sexual function.
Most cells involved in sexual arousal, the erection mechanism, and libido contain androgen receptors. Testosterone is in some sense the fuel for the sexual system, but the engine consists of many more components.
Normal values vary by laboratory, but clinical thresholds are generally set at:
- ≥ 12 nmol/L: normal functional range
- < 10.5-12 nmol/L: hypogonadism (low testosterone) in the most commonly used clinical definition
How Does Testosterone Affect Desire?
Sexual desire, also called libido, is the strongest correlate of testosterone. This is a consistent finding in the literature. Nguyen et al. (2022, Andrology) concluded in a comprehensive review that "reduced sexual desire is the most important correlate of male hypogonadism."
Concretely: among men with testosterone below 12 nmol/L, 40% showed secondary hypoactive sexual desire, a clinically categorised decline in libido without a clear other cause.
But, and this is crucial, erectile problems are much less strongly correlated with testosterone than libido. Erectile dysfunction is better explained by age, cardiovascular health, and metabolic factors than testosterone alone. Looking exclusively to testosterone for erectile problems misses the point.
When Does Testosterone Decline?
The European Male Aging Study (EMAS) followed more than 3,400 men from eight European countries and established that testosterone declines on average by 1-2% per year after age 30. This is a gradual, normal ageing process, not a disease.
But there are factors that accelerate that decline:
- Obesity: adipose tissue converts testosterone to oestrogen via the aromatase system; 40.7% of obese men have clinically low testosterone
- Type 2 diabetes: 30.7% of men with diabetes show testosterone deficiency
- Chronic stress: cortisol actively suppresses testosterone production via the HPA axis
- Sleep deprivation: testosterone is primarily produced at night; poor sleep = less testosterone. One study found 10-15% lower testosterone levels after one week of 5 hours of sleep per night
- Sedentary lifestyle: lack of exercise, particularly strength training, significantly lowers testosterone
What Can You Do?
Lifestyle Interventions with Evidence
Strength training has the strongest evidence level for raising testosterone in men of all ages. Two to three sessions per week with compound movements (squats, deadlifts, rows) consistently produce measurable hormonal responses.
Optimising sleep is the most underutilised intervention. Aim for 7-9 hours of quality sleep. Testosterone is primarily produced during the first 3 hours of sleep. Disrupting that window directly impairs production.
Weight loss in overweight men has one of the strongest effects on testosterone, sometimes comparable to the effect of testosterone replacement. Every kilogram lost reduces aromatase activity.
Stress reduction via exercise, meditation, or therapy lowers cortisol and removes the brake on testosterone production.
When Is Medical Advice Needed?
If lifestyle adjustments have no effect after 3-6 months, or if you experience symptoms that disrupt daily functioning (severe fatigue, depressive mood, significant libido loss), ask a doctor for a testosterone measurement via blood test. Self-medication with testosterone supplements without diagnosis is risky.
Sexual Pleasure Independent of Testosterone Levels
Here is something that is rarely said: sexual pleasure does not depend on testosterone levels. Arousal, sensation, orgasm: these are neural and vascular processes that function independently of hormone levels.
Men who actively explore their sexuality, both solo and with a partner, consistently report greater satisfaction, regardless of age or hormonal status. Prostate exploration and anal stimulation are anatomical pathways to pleasure that require no testosterone. They require curiosity and the right tools.
The ODES Ombre Prostate Vibrator is designed for exactly that: controlled, targeted stimulation of an erogenous zone that most men never systematically explore. Read our guide on cockrings for more on how sexual aids can support erectile function and pleasure.
The Verdict
Testosterone is real and it influences your libido. But it is not a simple switch, and low testosterone levels are rarely the only explanation for reduced sexual desire. Lifestyle, sleep, stress, and metabolic health are equally powerful, and partly adjustable, factors.
Start there: sleep better, move more, eat more varied, manage stress. Once that foundation is in order and desire still feels absent, a conversation with a doctor about testosterone levels becomes worthwhile.
In the meantime: exploring sexuality, solo or together, has its own value, regardless of hormone level. Browse our sex toys for him collection for products that facilitate that exploration.
Sources:
1. Nguyen V. et al. (2022). Testosterone and Sexual Desire: A Review of the Evidence. Andrology. SAGE
2. Wu F.C.W. et al. (2010). Identification of late-onset hypogonadism in middle-aged and elderly men. NEJM. European Male Aging Study.
3. Leproult R. & Van Cauter E. (2011). Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA, 305(21), 2173-2174.
