Statins are not known to directly cause urine to smell. No peer-reviewed study has identified a change in urine odor as a recognized side effect of any statin drug, and the effect does not appear on standard prescribing information for atorvastatin, rosuvastatin, simvastatin, or other members of the class. That said, the question is not as far-fetched as it might sound. Statins interact with liver metabolism, gut bacteria, and kidney function in ways that could plausibly nudge the chemistry of what ends up in your urine, and a few indirect pathways are worth understanding.
How Statins Leave the Body
Most statins are processed heavily by the liver and exit the body primarily through stool rather than urine. In a study of healthy men given rosuvastatin, roughly 90 percent of the dose was recovered in feces, with the remainder showing up in urine.1PubMed. Metabolism, excretion, and pharmacokinetics of rosuvastatin in healthy adult male volunteers Other statins follow a broadly similar pattern, though the exact split between fecal and urinary excretion varies by drug. Simvastatin and lovastatin, for instance, undergo extensive first-pass metabolism in the liver, and very little of the active drug reaches the kidneys. Atorvastatin is similar. Because only a small fraction of most statins ends up in urine, the drug itself is unlikely to be concentrated enough there to produce a noticeable smell.
This matters because many medications that genuinely change urine odor do so precisely because they, or their metabolites, are excreted in large amounts through the kidneys. Antibiotics like amoxicillin and certain B vitamins are classic examples. With statins, that renal concentration is generally low, which makes a direct drug-caused odor change unlikely for most people.
Gut Microbiome Changes and Their Downstream Effects
One of the more interesting indirect pathways involves the gut. Statins do not just lower cholesterol in the liver; they also reshape the community of bacteria living in your intestines, and those bacteria produce a wide range of compounds that eventually circulate through your blood and get filtered into urine. Research has shown that statins affect the metabolism of several key bacterial byproducts, including trimethylamine N-oxide (TMAO), short-chain fatty acids, and bile acids.2PubMed Central. A gut feeling of statin A meta-analysis found that statin treatment significantly decreased TMAO levels, while another study observed a dramatic drop in butyric acid production with statin use, even as other short-chain fatty acids remained unchanged.
TMAO is particularly relevant here because trimethylamine, its precursor, is the compound responsible for that distinctly fishy body odor in people with the metabolic condition trimethylaminuria. Under normal circumstances, your body converts trimethylamine efficiently into TMAO, which is odorless. But if statins are shifting TMAO metabolism, that altered chemistry could theoretically change the balance of volatile compounds circulating in the body. Whether this shift is large enough to produce a perceptible change in urine smell for typical statin users has not been tested directly, but the biochemical plumbing is there.
Bile acid metabolism is another piece of the puzzle. Statins influence the farnesoid X receptor pathway, which plays a central role in regulating bile acids and lipid metabolism.2PubMed Central. A gut feeling of statin Bile acids are sulfur-containing compounds, and changes in their metabolism can shift what your gut bacteria produce, which in turn changes the volatile organic compounds that reach your kidneys. Again, no study has drawn a straight line from “statin alters bile acid metabolism” to “patient notices urine smell,” but the mechanism is plausible enough that dismissing the connection entirely would be premature.
Could Statins Change How You Perceive Smells?
Sometimes the issue is not that something smells different but that you notice it differently. Hundreds of medications have been reported to alter taste and smell perception, either by their own sensory properties or by disrupting the biochemical pathways involved in how you detect odors.3PubMed Central. Influence of medications on taste and smell Most chemosensory side effects of drugs come not from the drug hitting your tongue or nose directly, but from the medication interfering with the enzymes and transporters your sensory cells depend on.
Statins are not among the drugs most commonly associated with smell disturbances, but they are known to occasionally cause taste changes, and the two senses are closely linked. If a statin slightly shifts your olfactory sensitivity, you might detect a urine odor that was always there but previously below your threshold of awareness. This is a subtle distinction, but it could explain why some patients become convinced the drug is changing their urine when the actual chemistry of the urine has not shifted much at all.
The Nocebo Effect and Subjective Side Effects
Statins are among the most widely prescribed drugs on Earth, and they carry an outsized reputation for side effects. Some of those side effects are real and well-documented, like muscle pain in a small subset of users. But a significant body of research suggests that many reported statin side effects are driven by expectation rather than pharmacology. One large crossover trial had patients rotate through months of taking a statin, a placebo, and no tablet at all. Symptom scores were significantly higher during statin months compared to no-tablet months, but they were equally high during placebo months, with no meaningful difference between statin and placebo.4PubMed Central. Side Effect Patterns in a Crossover Trial of Statin, Placebo, and No Treatment The calculated nocebo ratio was 0.90, meaning about 90 percent of the symptom burden patients attributed to the statin could be reproduced by a sugar pill.
A separate analysis of the FDA’s adverse event reporting system found that subjective side effects (symptoms the patient feels and reports, rather than things measurable on a blood test) were reported significantly more often for statins than objective ones. Those subjective complaints were also reported more frequently by women than men, and more often in the United States than in other countries, suggesting cultural and psychological factors play a role.5PubMed. Examining the Nocebo Effect of Statins Through Statin Adverse Events Reported in the Food and Drug Administration Adverse Event Reporting System A new urine smell is inherently subjective, which places it squarely in the category of complaints most susceptible to the nocebo effect. This does not mean the person is imagining it, but it does mean the statin may not be the cause even when the timing lines up perfectly with starting the drug.
Other Reasons Your Urine Might Smell After Starting a Statin
If you started a statin around the same time you noticed a change in urine odor, the statin is one of dozens of possible explanations, and frankly not the most likely one. Urine odor is affected by hydration, diet, supplements, other medications, and infections. Here are a few of the more common culprits people overlook when they focus on a new prescription:
- Dehydration: Concentrated urine smells stronger. Many people starting a new medication become more aware of their body generally, and they may notice a smell that was always present when they were mildly dehydrated.
- Dietary changes: Patients newly diagnosed with high cholesterol often overhaul their diet at the same time they start a statin. Increased intake of asparagus, cruciferous vegetables, garlic, and certain fish can all change urine odor noticeably.
- Supplements: B vitamins, especially B6, and fish oil supplements produce distinctive urine odors. If your doctor suggested these alongside a statin, the supplement may be the actual source.
- Urinary tract infections: UTIs are an extremely common cause of foul-smelling urine, and they can develop at any time regardless of statin use. Interestingly, one clinical trial found that pravastatin was associated with fewer repeat UTIs over roughly four years of follow-up, possibly because of the drug’s anti-inflammatory properties.6PubMed Central. Effect of pravastatin and fosinopril on recurrent urinary tract infections So if anything, statins might make UTI-related urine odor less likely over time, not more.
- Metabolic conditions: Uncontrolled diabetes can cause sweet or fruity-smelling urine. Liver or kidney problems can produce musty or ammonia-like smells. These conditions often coexist with the cardiovascular risk profile that led to a statin prescription in the first place.
The timing coincidence is powerful psychologically. You start a new pill, and a week later something about your body seems different. The human brain is very good at drawing causal lines between those two events. But unless the change disappears when you stop the statin and returns when you restart it, the association is just correlation.
Statins and Kidney Function
One scenario where statins could plausibly contribute to a urine change involves kidney stress. A large population-based study found that high-potency statins (like high-dose atorvastatin or rosuvastatin) were associated with a modestly increased rate of hospitalization for acute kidney injury compared to low-potency statins, with the highest risk in the first 120 days of use.7PubMed Central. High-Potency Statins and Acute Kidney Injury–Associated Hospitalizations To put this in perspective, roughly 1,700 patients needed to be treated with a high-potency rather than low-potency statin for 120 days to produce one additional hospitalization. The risk is real but small.
When kidneys are under stress, even mildly, they filter waste products differently. Protein might leak into the urine, or the concentration of certain metabolites shifts. Both of these can change how urine looks and smells. Foamy urine, darker color, and a stronger ammonia-like smell can all signal that the kidneys are working harder than usual. If you notice a persistent change in urine odor along with other signs like swelling in the legs, fatigue, or decreased urine output, that combination is worth bringing to your doctor’s attention regardless of whether you are on a statin.
For people who already had chronic kidney disease before starting a statin, the picture was reassuring in the same study: no significant increase in acute kidney injury risk was found in that group. The elevated risk appeared concentrated among people with previously normal kidney function who were started on the highest doses.
When Urine Odor Actually Warrants Attention
Doctors have long recognized that the smell of a patient’s body fluids can provide diagnostic clues. A 1980 medical review noted that characteristic patient odors accompany many diseases and intoxications, and recognizing them can guide both laboratory evaluation and treatment decisions.8PubMed. Olfactory diagnosis in medicine A brief change in urine odor that resolves on its own is almost never concerning. But certain persistent smells do warrant a check-in with a healthcare provider:
- Sweet or fruity: Can indicate high blood sugar or diabetic ketoacidosis, especially if accompanied by increased thirst and frequent urination.
- Strong ammonia: Often just dehydration, but persistent ammonia smell can reflect kidney issues or a urinary tract infection.
- Foul or rotten: Typically a urinary tract infection, especially if paired with burning, urgency, or cloudy urine.
- Musty or mousy: Rarely, this can signal a liver problem or certain metabolic disorders.
If you are on a statin and notice a new urine odor, the most useful first step is simple: increase your water intake for a few days and see if it resolves. If it does, dehydration was the likely explanation. If it persists, a basic urinalysis and metabolic panel can quickly rule out infections, kidney dysfunction, and blood sugar issues. Asking your doctor to check liver enzymes at the same visit makes sense, since statins can occasionally elevate liver markers, and liver dysfunction can change the smell of body fluids.
Why This Side Effect Stays Anecdotal
Clinical trials of statins have enrolled hundreds of thousands of patients, and the side effect profiles of these drugs are among the most thoroughly documented in all of medicine. Muscle complaints, liver enzyme elevations, and a small increase in diabetes risk are the headline adverse effects, all established through rigorous trials. Urine odor has never surfaced as a statistically significant finding in any of these studies. That does not prove it never happens to anyone, but it does strongly suggest that if the effect exists, it is either extremely rare or too mild for participants to report consistently.
Part of the challenge is that urine odor is inherently difficult to study. It is subjective, variable from hour to hour based on hydration and diet, and not something clinical trials routinely measure. Researchers track kidney function with blood tests like creatinine and estimated glomerular filtration rate, but they do not generally ask patients to describe how their urine smells. An effect that is real but uncommon could easily hide in the noise of a large trial, unasked and therefore unreported.
Online patient forums are full of reports connecting statins to unusual body odors, including urine. These reports are worth taking seriously as signals that something is going on in some people’s experience, but they cannot distinguish between a pharmacological effect and the many confounders mentioned earlier. Until a controlled study specifically examines volatile urinary compounds in statin users versus matched controls, the honest answer remains: it has not been demonstrated, but it has not been convincingly ruled out either. If you are experiencing it, the change is far more likely to stem from one of the other causes on the list above than from the statin itself.