Almost every woman has stood in a bathroom at some point wondering whether something is wrong, and almost none has asked anyone.
The short version: you are supposed to have a scent, it is supposed to change through the month, and there is one specific change worth acting on. This article is about telling those apart.
In this article
- You are supposed to smell like something
- The number that explains the monthly change
- What changes across the cycle
- The one that is not normal
- Other causes of a change
- What makes it worse
- What actually helps
- When to see someone
- Frequently asked questions
You are supposed to smell like something
Everyone has a unique scent and that is completely normal. A healthy vulva is not odourless, and no product should be aiming to make it so.
The usual descriptions of normal: slightly musky, slightly tangy or sour, sometimes metallic around a period, occasionally faintly sweet. Sour and tangy are good signs, because they are the smell of an acidic environment doing its job.
Odourless is not the target. The entire "feminine freshness" category is built on persuading women otherwise, and the products sold on that promise are among the most common causes of the irritation that follows.
The number that explains the monthly change
Vaginal pH usually sits at 4 to 4.5. That acidity is produced by lactobacilli and it keeps other organisms suppressed. The full explanation is in vaginal pH explained.
During menstruation, vaginal pH can rise to 6.6.
That is a large shift, and pH is logarithmic so it is much larger than it looks. At 6.6 the environment temporarily favours anaerobic bacteria, and those bacteria produce compounds that smell.
That one number explains most of what women notice month to month, and it explains why the change is temporary and self-correcting.
What changes across the cycle
Around your period. pH rises toward 6.6, blood itself sits near 7.4, and the smell often becomes metallic or stronger. Normal, and it resolves.
Mid-cycle. Discharge is often most pronounced around ovulation, so scent can be more noticeable then too. Also normal.
After sex. Semen sits at around pH 7.2 to 8, so it temporarily raises pH and can change the smell for a day. Normal.
After exercise. Sweat from apocrine glands in the area is a skin smell rather than a vaginal one, and it resolves with a shower.
The pattern that reassures: it changes, and it comes back. Cyclical variation returning to your baseline is the system working.
The one that is not normal
A fishy smell.
The chemistry is specific. Anaerobic bacteria produce compounds called biogenic amines as metabolic byproducts, notably putrescine, cadaverine and trimethylamine. Those are the same chemicals responsible for the smell of decaying fish.
Trimethylamine has a strong fishy odour even at very low concentrations and it is what produces the smell associated with bacterial vaginosis.
BV is not an infection you catch. It is a shift in the bacterial population, where lactobacilli lose dominance and anaerobes take over. That is why it follows anything that raises pH, and why it is more likely after a period, after sex, and after douching.
What to act on: a strong, unfamiliar, unpleasant odour, especially fishy, that continues for several days, particularly with greyish-white discharge, burning or itching. That combination is worth a test rather than a product. More detail in bacterial vaginosis.
It also frequently has no other symptoms, which is why the smell alone is worth taking seriously rather than washing away.
Other causes of a change
- A forgotten tampon. Produces a very strong, foul odour. More common than anyone admits, and easily resolved.
- Diet. Asparagus, garlic, onions, spices and alcohol can all shift body odour temporarily.
- Medication. Antibiotics disturb the bacterial population, and that shift can produce odour and yeast overgrowth.
- Sweat and clothing. Synthetic fabric holds moisture against skin.
- Hormonal change. Pregnancy, breastfeeding and perimenopause all change the environment. After menopause, falling estrogen reduces the glycogen lactobacilli feed on, so pH rises and odour can change permanently rather than cyclically.
- Trichomoniasis, a sexually transmitted infection, which can produce a frothy discharge and a strong odour and needs testing.
What makes it worse
Nearly everything marketed to fix it.
Douching. Removes lactobacilli, raises pH, makes BV more likely. ACOG advises against it.
Soap. Alkaline at pH 9 to 10 against skin near 4.7. Detail here.
Scented washes, sprays, wipes and liners. Fragrance masks and irritates.
Overwashing. Strips the barrier and can worsen the smell it is aimed at.
Deodorising products. Cover the signal without touching the cause, which is how a treatable bacterial shift goes unaddressed for months.
What actually helps
Stop masking it. The smell is information.
Wash the vulva only, once daily, with water or something appropriate to the pH. Never inside.
Cotton underwear, unscented detergent, no fabric softener.
Change out of damp clothing promptly.
Support rather than strip. A prebiotic approach works with the flora rather than removing it, which is the opposite mechanism to a deodorising wash.
Keep the barrier intact. Skin that is dry and irritated is more reactive to everything, which is what an external balm supports.
And get tested if it is fishy and persistent. BV is usually treated with prescribed antibiotics. No wash resolves it.
When to see someone
- A fishy odour lasting more than a few days
- Any strong, unfamiliar, unpleasant odour
- Odour with greyish-white or green discharge
- Odour with itching, burning or pain
- Frothy discharge
- Odour with fever or pelvic pain
- A tampon you cannot retrieve
Frequently asked questions
What does a healthy vulva smell like?
Everyone has a unique scent. Commonly described as slightly musky, tangy or sour, sometimes metallic around a period. Sour and tangy reflect an acidic environment doing its job. Odourless is not the goal, and products promising it usually cause more problems than they solve.
Why does it smell stronger during my period?
Vaginal pH usually sits at 4 to 4.5 and can rise to 6.6 during menstruation, which temporarily favours anaerobic bacteria that produce odour compounds. Menstrual blood itself sits near pH 7.4. It resolves as pH returns.
What does a fishy smell mean?
It is most often bacterial vaginosis. Anaerobic bacteria produce trimethylamine, which has a strong fishy odour at very low concentrations. A fishy smell lasting more than a few days, especially with greyish-white discharge, is worth testing rather than washing.
Can I use a deodorant for it?
You can and it works against you. Deodorising products mask the signal, are usually alkaline and fragranced, and both of those make the underlying environment worse. If there is an odour worth masking, there is usually a cause worth identifying.
Why does it smell different after sex?
Semen sits at around pH 7.2 to 8, so it temporarily raises vaginal pH and changes the scent for a day or so. That is normal. A persistent change after sex, particularly a fishy one, is worth a test.
Does diet change vaginal odour?
It can, temporarily. Strongly flavoured foods including garlic, onions, asparagus and spices, plus alcohol, affect body odour generally. These changes are mild and short-lived, and diet does not explain a persistent strong odour.
Sources
- Vaginal odour, types and causes: Cleveland Clinic
- Trimethylamine content in vaginal secretion and its relation to bacterial vaginosis: PubMed 12588422
- Vaginal and vulvar pH: PMC7168340
- Douching guidance: ACOG