A musty or earthy smell most strongly indicates the presence of mold or mildew. This odor is caused by Microbial Volatile Organic Compounds (mVOCs) released into the air as the fungi grow and break down materials in damp environments.
A musty smell in your home usually means excess moisture, mould, or poor ventilation. It's more than just unpleasant—it can indicate serious damp issues and, whether it's damp, mould, poor ventilation or hidden leaks, ignoring the problem can lead to long-term damage and even health concerns.
If the musty smell is "ghostly" (nobody else can smell it), you may be experiencing phantosmia (an olfactory hallucination where your brain registers an odor that isn't physically present).
A musty body odor is usually caused by trapped moisture that allows bacteria or fungi to break down sweat and skin proteins. This distinct, earthy smell can also stem from dietary choices, metabolic conditions, or environmental factors.
A sudden change to a "musty" or earthy body odor is incredibly common and usually harmless, but it can be a clue that something in your environment or daily routine has shifted.
Liver disease – Can create a musty odor. Thyroid disorders – Overactive thyroid increases sweating. Trimethylaminuria (TMAU) – A rare genetic condition causing a fish-like odor.
A musty smell is a major warning sign. It typically indicates the presence of mold, mildew, or bacteria thriving in a damp, poorly ventilated environment. While the smell itself won't immediately cause severe harm, inhaling the airborne spores and gases it produces poses real health risks.
Even if you don't see visible mold, musty odors can still result from hidden water damage, poor ventilation, or excess humidity.
Uncontrolled diabetes most commonly causes a sweet, fruity, or solvent-like scent—similar to nail polish remover (acetone) or overripe fruit. This is caused by a buildup of chemicals called ketones, which are produced when the body burns fat instead of glucose for energy.
Riboflavin (Vitamin B2)
But people with certain gene changes, or liver or kidney dysfunction, may not be able to process it. TMA that builds up is eventually released through sweat, urine, reproductive fluids, and breath, causing a strong, fishy odor.
A musty body odor is most commonly caused by a rare metabolic genetic disorder called Phenylketonuria (PKU) or serious liver dysfunction, such as liver failure, which produces a distinct scent known as fetor hepaticus.
Low estrogen, common during perimenopause and menopause, typically causes body odor to become more intense, musky, or sour due to shifts in sweat composition and vaginal pH. Vaginal scent may change to become more alkaline, sometimes described as slightly sweet, bready, or yeasty. Other common smells include a sharper, stronger, or onion-like scent underarms or in the groin.
One of the easiest ways to detect it is by smell—black mold emits a strong, musty odor often compared to rotting plants, damp paper, or cedar wood. If you're unsure whether you're detecting mold, ask someone with a “fresh nose” to confirm, as you may have become desensitized to the smell in your home.
A musty or mildew-like smell on a person typically results from bacteria or fungi breaking down sweat and oils on the skin, or it can stem from lingering moisture in clothing.
The "nonenal" (2-Nonenal) odor typically begins to appear around the age of 40. This natural aging process occurs when the body's antioxidant defenses decline and skin lipid production changes, producing omega-7 unsaturated fatty acids that oxidize in the air to create the signature grassy, musty scent.
Mold smells earthy, damp, and stale. The distinct odor comes from microbial volatile organic compounds (mVOCs) released as mold grows.
High blood sugar (hyperglycemia) occurs when your body doesn't produce enough insulin or can't use it effectively. Five common warning signs include:
Kidney disease-related body odor typically smells like ammonia, urine, or bleach. Because the kidneys cannot effectively filter waste products, excess nitrogen and urea build up in the body and are released through sweat and saliva, sometimes resulting in breath described as smelling like "cat pee".
Yes, you can smell signs of diabetes. When the body struggles to process sugar, it burns fat instead, producing acids called ketones. This creates a distinct, fruity, sweet, or acetone-like smell (similar to nail polish remover) on the breath or in sweat.
You can usually see or smell a mold problem. Mold can appear as slightly fuzzy, discolored, or slimy patches that increase in size as they grow. Most molds produce musty odors that are the first indication of a problem. Mold can grow anywhere there is adequate moisture or a water problem.
A musty room without visible mold usually means mold is growing out of sight (like inside walls, ductwork, or under carpets), or excess moisture is rotting materials. It can also stem from hidden plumbing leaks, stale dust, or an unmaintained HVAC system.
The characteristic "old age smell" is scientifically known as nonenal (or 2-nonenal). It is a chemical compound produced when the skin's natural oils and fatty acids break down and oxidize as we age.
A musty body odor is most commonly caused by a rare metabolic genetic disorder called Phenylketonuria (PKU) or serious liver dysfunction, such as liver failure, which produces a distinct scent known as fetor hepaticus.
Mold toxicity (mycotoxin illness) happens when prolonged exposure to mold spores triggers chronic inflammation and immune system activation. Symptoms are often subtle and mimic other illnesses, but common red flags include persistent allergy-like reactions, chronic fatigue, unexplained brain fog, recurring headaches, and respiratory or digestive distress.
Additionally, spraying a solution of equal parts vinegar and water or a diluted hydrogen peroxide solution into the air can help to kill airborne mold spores.