A noticeable smell from your penis is almost always caused by bacteria breaking down sweat, dead skin cells, or trapped moisture in the groin area. In most cases, it’s a hygiene issue that’s easy to fix. Sometimes, though, a persistent or worsening smell signals an infection that needs treatment.
How Bacteria Create the Smell
Sweat itself is essentially odorless. The smell comes from bacteria on your skin feeding on sweat, oils, and dead skin cells. Your groin has a high concentration of apocrine glands, the same type found in your armpits. These glands produce a thicker, fattier sweat that bacteria love to break down, and the byproducts of that process are what you actually smell.
The groin is warm, dark, and often damp, which makes it one of the most bacteria-friendly zones on your body. Add tight clothing or synthetic underwear that traps moisture against the skin, and you’ve created ideal conditions for odor. Cotton underwear, while breathable, absorbs moisture without wicking it away, essentially holding a damp layer against you all day. Moisture-wicking fabrics tend to keep things drier and reduce bacterial growth.
Smegma Buildup
If you’re uncircumcised, the most common cause of a strong smell is smegma, a whitish, sometimes cheesy-looking buildup under the foreskin. Smegma is a combination of oils from your skin’s sebaceous glands, dead skin cells, and sweat. It’s not harmful in small amounts, but when it accumulates, it develops a noticeable odor.
The space under the foreskin is warm and low in oxygen, which encourages the growth of anaerobic bacteria. Research on the penile microbiome has found that the subpreputial space (the area under the foreskin) harbors specific families of anaerobic bacteria, including several genera also associated with the strong odor of bacterial vaginosis. These bacteria thrive in that enclosed environment and are a major contributor to smell.
The fix is straightforward: gently pull back the foreskin and wash underneath with water each day. A mild, unscented soap is fine but not required, and too much soap can actually irritate the skin. After washing, pat the area dry and slide the foreskin back into place before getting dressed. If you notice heavy smegma buildup or a strong smell, you may need to clean more frequently.
Yeast Infections
Men can get yeast infections too. A yeast infection on the penis, called candidal balanitis, happens when naturally occurring fungus overgrows in the warm, moist skin folds. You’ll typically notice a thick white substance collecting in skin folds, areas of shiny white skin, and itching or burning. The smell is often described as musty or bread-like.
Yeast infections are more common in uncircumcised men, people with diabetes, and anyone who has recently taken antibiotics (which can disrupt the normal balance of microorganisms on the skin). Over-the-counter antifungal creams often clear it up, but if symptoms don’t improve within a week or keep coming back, it’s worth getting checked out.
Balanitis
Balanitis is inflammation of the head of the penis, and it’s one of the more common reasons for a persistent bad smell. It can be caused by bacterial overgrowth, yeast, or irritation from soaps, detergents, or condoms. The warm, moist environment under the foreskin makes it particularly easy for bacteria and yeast to take hold.
Common signs include redness, swelling, soreness, a bad smell, and sometimes a white, cheesy discharge. Balanitis can also be triggered by sexually transmitted infections like gonorrhea or chlamydia, so if the smell comes with unusual discharge, pain during urination, or sores, those are signs to get tested.
STIs That Cause Odor
Most sexually transmitted infections in men don’t produce a noticeable smell, but there are exceptions. Trichomoniasis, a common parasitic infection, can cause a frothy discharge from the penis with a foul smell. Most men with trichomoniasis show no symptoms at all, so when odor and discharge do appear, they’re worth taking seriously.
Gonorrhea and chlamydia can also produce discharge that carries an odor, though the more obvious symptoms are usually burning during urination or a yellowish-green discharge. If you’re sexually active and notice a new or unusual smell alongside any of these symptoms, testing is the clearest path to an answer.
Daily Habits That Reduce Odor
Most penile odor comes down to moisture, bacteria, and how long they sit together. A few practical changes make a significant difference:
- Wash daily with water. If you’re uncircumcised, gently retract the foreskin and rinse underneath. Don’t scrub. A gentle soap is optional but avoid heavily fragranced products, which can irritate the skin and paradoxically make odor worse by disrupting your skin’s natural bacterial balance.
- Dry thoroughly. Pat the area dry after showering, especially under the foreskin. Bacteria thrive in moisture, so this step matters more than most people realize.
- Choose the right underwear. Moisture-wicking synthetic fabrics or merino wool keep the area drier than cotton. Change your underwear daily, and swap them out after heavy sweating or exercise.
- Wash your hands before touching your penis. This includes before urinating. Your hands carry bacteria from everything you’ve touched throughout the day.
If a smell persists despite consistent hygiene, or if it’s accompanied by redness, itching, discharge, or pain, that’s your body telling you something beyond sweat and bacteria is going on. An infection, whether fungal, bacterial, or sexually transmitted, is the most likely explanation at that point, and most are easily treatable once identified.