A bloke’s guide to sweat, chafe and smell in an Australian summer

Why your skin cops it harder after 40

Why this summer feels rougher than the old days

January in Australia is often hot. Recent seasons have included repeated severe heatwave warnings, with large parts of the country seeing temperatures in the high thirties and low forties over several days in a row.

If you are a bloke over 40, you may have noticed something else:

• inner thighs rubbing raw on a short walk
• underarms burning after you change deodorant
• nipples chafing after a run or a long day in a work shirt
• groin and bum crack feeling constantly “off” by the end of a shift

None of this is glamorous. Most of it is very common. And a lot of it comes down to heat, sweat, friction and a skin barrier that is not as forgiving as it was at 25.

This is a straight, science based guide you can read yourself or that a partner can hand you without eye rolling.

Sweat, smell and skin – what is actually going on

Sweat itself does not stink

Sweat, on its own, is almost odourless. The smell comes when bacteria on the skin break sweat down into smaller molecules that have a strong odour. Apocrine glands in the armpits and groin produce sweat that is richer in protein and lipids, which bacteria particularly enjoy.

Deodorant versus antiperspirant

There is a key difference:

• Deodorants
  • aim to control odour
  • often use antimicrobial ingredients and fragrances to reduce or mask smell
  • do not block sweat glands
• Antiperspirants
  • use aluminium based salts to temporarily block or plug sweat ducts
  • reduce how much sweat comes out of the skin
  • are regulated as medicines or therapeutic goods in some systems because they change a body function

Both are considered safe for everyday use by major regulators, but some people prefer aluminium free options for personal reasons.

Why it feels worse after 40

As you age:

• the outer skin barrier can become drier and less elastic
• you may carry a bit more weight around the middle or inner thighs, which increases fold and seam friction
• long term sun, work gear, sport and previous skin problems leave some areas more vulnerable

So the same shorts, hi vis shirt or deodorant that were fine in your thirties can start to cause issues.

Chafe zones: thighs, nipples, groin and bum crack

Inner thighs and groin folds

In hot weather, skin on skin plus sweat plus movement is the classic recipe for intertrigo – the red, sore “sweat rash” that shows up where skin rubs. Doctors caution that tight or synthetic underwear in summer increases this risk, especially in the groin.

Warning signs:

• red, glazed looking skin in the crease
• burning, stinging or tenderness
• sometimes a secondary infection on top, if bacteria or yeasts take advantage

What helps:

• breathable underwear with a decent leg length to stop bare skin rubbing
• avoiding very tight synthetic gear for long days in the heat
• changing out of wet or sweaty clothes as soon as you can
• gently washing and then patting dry folds, not scrubbing

If the rash is very sore, weeping, has a strong smell or does not settle, you need a GP or dermatologist to check for infection and prescribe proper treatment.

Nipples

Runners, cricketers, surf lifesavers and tradies in rough work shirts all know the feeling of nipples rubbed almost raw by the end of the day.

Practical fixes:

• softer, smoother inner layers under rough team shirts or hi vis
• adhesive nipple covers for long runs or events
• washing tops without heavy fragrance that can sting broken skin

Persistent cracks or colour change around the nipple should always be checked by a doctor.

Bum crack and perianal area

Long drives, labouring, cycling or sitting in a hot office chair can all leave the skin between the buttocks sore.

Rules of thumb:

• keep cleansing simple, avoid aggressive scrubbing or scented wipes
• change out of sweaty underwear when you get home
• if you see persistent redness, oozing or bleeding, do not self diagnose – see a clinician
• do not apply strong antifungals or steroid creams without advice to this area

Underarms: product choices that respect skin and smell

Picking your lane

If your main issue is wet patches, you probably need an antiperspirant. If the main issue is smell, a deodorant alone may be enough.

For blokes over 40 with more sensitive skin, practical considerations include:

• avoid heavy fragrance if your armpits already sting or are rashy
• be wary of deodorants with high levels of baking soda if you have sensitive skin, as they can shift pH too far alkaline
• do not apply to broken or freshly shaved skin

Zinc ricinoleate and newer deodorant tech

Some modern aluminium free deodorants use zinc ricinoleate, a zinc salt derived from castor oil. It works by chemically trapping and absorbing odour molecules produced when bacteria break down sweat, so they cannot reach your nose, rather than blocking sweat glands or killing bacteria outright.

Key points from technical data:

• it does not stop you sweating, so it is not an antiperspirant
• it does not have to kill skin bacteria to work, which helps respect the skin microbiome
• it is usually used at a few per cent in deodorant sticks, creams or gels

This kind of technology can suit men who want odour control without aluminium, heavy scent or a greasy feel, particularly when used in a light, water based gel format that dries down quickly.

Whole body deodorants – where is the line

There is a trend towards whole body deodorants marketed for use on feet, under breasts, groin and even genitals. Media reports note that these products often contain powders and acids to reduce odour in many areas, but experts also warn about fuelling “genital anxiety” and over treating completely normal smells.

For men 40 plus, sensible principles are:

• external skin only – never apply deodorant directly on mucosa or inside any body opening
• if a product stings, burns or causes a rash, stop and seek advice
• normal clean bodies have a mild smell, especially after a day at work or sport
• if smell suddenly changes or is accompanied by discharge, pain or rash, see a doctor rather than layering more products

A simple summer checklist for blokes 40 plus

You do not need a bathroom full of bottles. Start with basics.

1. Gear
   • cotton rich or technical fabrics that breathe
   • underwear that protects inner thighs from bare skin rubbing
   • socks that do not stay wet all day
2. Wash routine
   • lukewarm water, not scalding showers
   • unscented or low fragrance wash for groin and underarms
   • gentle pat dry into folds
3. Underarm plan
   • pick deodorant or antiperspirant based on whether wetness or smell is the bigger issue
   • consider aluminium free, microbiome respectful products if you mainly need odour control
4. Friction zones
   • watch inner thighs, nipples, folds and bum crack for early redness
   • change out of sweaty gear when you get home rather than sitting in it all night
5. Check in, do not tough it out
   • if skin is breaking, cracking or weeping, or if smell or discharge changes, see a GP or dermatologist
   • tell them what products you are using and what your job or sport involves

When to see a doctor, not just swap deodorant

You should seek medical advice if you notice:

• a rash that spreads, blisters or does not settle in a week
• pain, swelling, or broken skin in the groin, perianal area or thighs
• a new lump, sore nipple or any breast change that does not resolve
• sudden change in body smell with other symptoms such as weight loss, fevers or night sweats
• any sign of infection such as pus, severe tenderness or feeling unwell

It is never “soft” to get something checked early. It is simply maintenance for the only body you have.