Low libido is one of the most common health complaints people never bring up with their doctor. It gets dismissed as stress, aging, or just the way things are. But in most cases there is a specific hormonal mechanism behind it — and understanding that mechanism is the first step toward addressing it.
Here is what is actually happening.
The Key Players
Sex drive is not controlled by a single hormone. It is the result of a hormonal conversation involving several systems simultaneously.
Testosterone is the primary driver of libido in both men and women — yes, women too, just in smaller amounts. It is produced in the testes in men and in the ovaries and adrenal glands in women. Even a modest decline in testosterone produces noticeable reductions in desire, energy, and motivation.
Oestrogen plays a supporting role — particularly in women. It maintains vaginal tissue health, supports mood stability, and amplifies the brain’s sensitivity to arousal signals. When oestrogen drops, as it does during perimenopause, libido often drops with it.
Dopamine is the neurotransmitter of desire and anticipation. It is what makes you want things — including sex. Low dopamine produces a flat, unmotivated baseline where nothing feels particularly appealing.
Cortisol — your stress hormone — is testosterone’s direct antagonist. When cortisol is chronically elevated, testosterone production drops. The body prioritises survival over reproduction. This is not a malfunction — it is evolutionary logic. But in modern life, where stress is chronic rather than acute, it becomes a persistent problem.
What Disrupts These Hormones
Chronic Stress As above — sustained high cortisol suppresses testosterone and blunts dopamine signalling. If your libido disappeared during a particularly stressful period and never fully returned, this is the most likely explanation. The stress response downregulates reproductive function because the body does not consider it a priority when under threat.
Poor Sleep Testosterone is primarily produced during deep sleep. Studies show that even one week of sleeping less than six hours per night reduces testosterone levels in young men by 10 to 15 percent. The effect in women is less studied but consistent in direction. Chronic sleep deprivation is one of the most reliable ways to tank your hormonal health across the board.
Excess Body Fat Adipose tissue — body fat — contains an enzyme called aromatase that converts testosterone into oestrogen. Higher body fat means more aromatase activity, which means lower testosterone and higher oestrogen in both men and women. This creates a self-reinforcing cycle — lower testosterone reduces motivation to exercise, which increases body fat, which further reduces testosterone.
Hormonal Contraceptives Some forms of hormonal contraception — particularly combined oral contraceptives — increase sex hormone binding globulin, a protein that binds to testosterone and renders it inactive. For some women this has a noticeable effect on libido. This is well-documented in the research but frequently underdiscussed in clinical settings.
Thyroid Dysfunction Both hypothyroidism and hyperthyroidism affect sex hormone production and libido. The thyroid regulates metabolic rate and has widespread effects on hormonal balance. If you have unexplained low libido alongside fatigue, weight changes, or temperature sensitivity, thyroid function is worth checking.
Antidepressants SSRIs — the most commonly prescribed antidepressants — frequently reduce libido and delay or inhibit orgasm as a side effect. This affects an estimated 40 to 65 percent of people taking them. It is one of the most common reasons people discontinue medication without telling their doctor.
What Actually Helps
Addressing the root cause is always more effective than chasing symptoms. That means:
- Prioritising sleep above almost everything else for hormonal health
- Managing chronic stress through the nervous system regulation techniques that actually work — exercise, breathwork, reduced stimulant intake
- Strength training — resistance exercise is one of the most reliable natural testosterone boosters in both sexes
- Getting bloodwork done — a full hormonal panel including free testosterone, oestrogen, SHBG, thyroid, and cortisol gives you an actual picture rather than guesswork
- Having an honest conversation with your doctor about any medications that may be contributing
The Bottom Line
Low libido is rarely just psychological and almost never inevitable. It is a symptom — and like most symptoms it is pointing at something specific. The hormonal mechanisms are well understood. The disrupting factors are largely modifiable.
Start with the basics — sleep, stress, and bloodwork. In most cases the answer is already there.
This article is for informational purposes only. Always consult a qualified healthcare professional regarding hormonal health concerns or before making changes to any medication.
