Puberty hormones begin before adolescence
Many believe puberty hormones first appear during adolescence, but experts say they are active much earlier. Dr Sasha Howard, clinical reader in paediatric endocrinology at Queen Mary, University of London and Barts Health NHS trust, explains that oestrogen, progesterone, and testosterone are active in the womb and during a phase called mini-puberty from two to six months of age. This period primes reproductive organs for future fertility. A three-month-old baby boy can have testosterone levels as high as an adult man. During mini-puberty, testicles double in size and boys often have spontaneous erections. In boys, mini-puberty usually ends by six months; in girls, activity can continue until one to two years old. The notion of a testosterone surge in four-year-old boys is a myth—reproductive hormones are quiet between ages two and ten.
Hormones affect both sexes equally
Hormones are not just a female issue. Dr Saira Hameed, consultant endocrinologist at Imperial College Healthcare NHS trust and author of Signals: The Inside Story of Our Hormones, says hormones affect men and women equally. Both sexes have the same hormones—testosterone and oestrogen—but in different levels. Thyroid function, cortisol, insulin, and blood sugar tests show no gender difference. Apart from fertility, there is no gender specificity to hormones.
Testosterone does not cause aggression at therapeutic doses
The idea that testosterone makes you aggressive is mostly false. Dr Channa Jayasena, professor of reproductive endocrinology at Imperial College London, says testosterone given to men with insufficient levels is incredibly safe and can improve mood and quality of life. Aggression occurs only when taken without medical guidance, such as anabolic steroids at hundreds to thousands times the needed dose, which affects the limbic system and can trigger aggression.
Cortisol is not inherently bad
Cortisol is the body's main stress hormone, but it is not inherently bad. Dr Hameed explains that short-term cortisol spikes sharpen thinking and alertness, which can be helpful. Chronic high cortisol due to stress is problematic, but the solution is stress reduction—spending time with loved ones, exercise, sleep, and good nutrition—not supplements like cortisol rebalancing tea.
Menopause experience is not hereditary
Dr Gillian Goddard, endocrinologist and adjunct assistant professor at NYU Langone Hospital, says women often think their mother's menopause predicts their own, but genetics mainly affect the timing of the last menstrual period, not the severity of symptoms. There is significant person-to-person variability.
Puberty stops growth
It is true that growth stops after puberty. Dr Howard explains that oestrogen closes the growing ends of bones, halting height increase. Most adult height is achieved before puberty, so early intervention is key for growth concerns.
Childhood obesity affects hormones
Data from the National Child Measurement Programme for 2024-25 shows 10.5% of reception children and 22.2% of year 6 children were obese. Dr Howard says excess weight leads to earlier puberty timing because the hypothalamus is not equipped to handle excess weight, triggering early puberty signals.
Hormone balancing is unnecessary
The body's hormone levels are precisely calibrated, says Dr Hameed, with many checks and balances. Dr Goddard adds that fluctuations maintain homeostasis. The idea of balancing hormones comes from supplement marketing, but there is little evidence that supplements significantly benefit hormonal health.
Testosterone and oestrogen benefit both sexes
Testosterone is not only for men, nor oestrogen only for women. Dr Jayasena says oestrogen plays a role in male sexual function, and testosterone can increase libido in menopausal women. In men, testosterone works partly by being broken down into oestrogen in fat cells, brain, and bones.
Modern HRT is safe
A 2002 US study linked HRT to increased breast cancer risk, but subsequent analysis found issues: the study focused on older women and used synthetic hormones. Dr Jan Toledano from the London Hormone Clinic says current body-identical HRT is safe, like refuelling with the right fuel. However, the NHS advises extra caution for those with breast cancer or blood clot susceptibility.
Menopause weight gain is real
According to the British Menopause Society, weight gain affects at least 50% of women during perimenopause and menopause. Dr Goddard explains that oestrogen drop shifts fat storage to the midsection, increasing insulin resistance and diabetes risk. Women also lose about half a kilo of muscle mass, which reduces calorie burning. She recommends strength training, reducing carbohydrates, and increasing fibre and protein, focusing on overall health metrics rather than just weight.
Girls are starting puberty earlier
Studies show girls enter puberty about a year earlier but get their first period only six months earlier, lengthening puberty. Dr Goddard notes that this trend dates back to the 1850s, initially due to better nutrition. Today, theories include childhood obesity increasing oestrogen and endocrine-disrupting chemicals affecting the hypothalamus.
Melatonin helps sleep onset, not maintenance
Melatonin, produced by the pineal gland, regulates circadian rhythm and rises at night. Dr Goddard clarifies that melatonin signals the brain to wind down but does not help people stay asleep. Different sleep issues require different solutions.
