01/04/2026
Have you noticed that your body odour has changed when you hit 40s?
There are several biological reasons for this!
đđ˝1. Falling oestrogen alters sweat production
As oestrogen levels fluctuate and gradually decline, the bodyâs temperature regulation becomes less stable. This leads to hot flushes and night sweats, which increase overall sweating. More moisture on the skin creates an ideal environment for odourâproducing bacteria to thrive
đđ˝2. Greater relative androgen (testosterone) effect
When oestrogen drops, testosterone becomes relatively more dominant. Androgens stimulate apocrine sweat glands (found in the armpits and groin), which release a thicker, proteinâ and lipidârich sweat. When skin bacteria break this down, it produces a stronger, muskier smell compared with normal eccrine sweat
đđ˝3. Changes in the skin microbiome and pH
Oestrogen helps maintain a balanced skin microbiome. Lower levels can shift the mix of skin bacteria toward species that produce more pungent odour compounds. Skin pH may also change, further favouring these bacteria
đđ˝4. Stress and anxietyârelated sweating
Perimenopause is often associated with increased anxiety. Stress sweat (also from apocrine glands) contains more proteins and fats than heatârelated sweat, making it more likely to smell when broken down by bacteria
đđ˝5. Heightened or altered sense of smell
Some women notice odour changes partly because smell perception itself changes in perimenopause (dysosmia or increased sensitivity). This can make normal body scents seem stronger or unfamiliar, even if others donât notice a difference
6. Ageârelated compounds (e.g. 2ânonenal)
With age and hormonal change, the skin produces more fatty acids that oxidise into 2ânonenal, a compound associated with a stronger, lingering âmustyâ or âonionâlikeâ odour. This is not waterâsoluble and can persist despite good hygiene
