Your sweat smells like marijuana: Food, genes and the microbiome are to blame

Each sweat smells a little different. And many people may think the smell of marijuana from their armpits is strange and may even be a sign of a health problem. But in reality, this phenomenon is surprisingly more common than it might seem. And there are no secret habits behind it. Sweat with a marijuana smell is often the result of a complex combination of biology, diet and the skin microbiome.

Are you one of those people who have this “problem” and are embarrassed by it? Don’t worry, you’re definitely not alone. In fact, marijuana-like odor is quite common. And it’s not always a sign of health problems. The smell of sweat changes based on what you consume, how your hormones are doing, and what state your body is in overall.

The basic mechanism of odor

Sweat itself is almost always odorless. It’s only the bacteria living on your skin that triggers the unpleasant or strange odor. They metabolise organic substances in sweat, such as proteins and lipids. These then convert them into volatile compounds that are perceived by the sense of smell. The apocrine sweat glands, which are located in the armpits or groin, for example, play a key role. Sweat from these glands is thicker and richer in fats, proteins and steroid compounds.

If specific bacteria are involved, such as those in the Staphylococcus or Corynebacterium genera, the result can be an odour reminiscent of rot, rotten meat, or what has been described as a marijuana smell. However, it can also be caused, for example, by what you had to eat that day or by your hormones.

What pot has to do with herbs and food

One of the most commonly cited hypotheses is that sweat may resemble marijuana due to so-called terpenes, aromatic compounds found in many plants, including cannabis. These terpenes in plants and foods can be taken up into the body and, when this happens, can bind to fat cells. Later, perhaps during physical activity or stress, they are released and excreted in sweat. Combined with the microbial transformation of sweat substances on the skin, this produces a smell that can strongly remind some people of marijuana.

However, it is important to note that not every person will experience this effect. It always depends on individual genetics, the composition of the skin microbiome and what you eat. For example, some common foods and spices (garlic, onions, spicy foods) contain sulfur compounds that can contribute to this odor.

Other factors affecting sweat odour

Many factors affect how your sweat smells. If you too are affected by an unpleasant marijuana-like aroma, one of these things may be to blame:

• Genetics and microbiome variability: People differ in how their sweat is composed, what hormones they produce, and what skin they have with different bacteria. Studies show that the microbiome of the armpit can vary substantially from person to person, or even from one person on both arms. This means that even if two people have eaten the same food, their sweat may smell completely different.
• Stress, emotional state and activation of the apocrine glands: Apocrine glands are most often activated in moments of stress, tension, sexual arousal or fear. This means that someone may smell marijuana sweat just when they are stressed, for example, before a performance, a sport, a busy day.
• Health and metabolic abnormalities: although less common, there are metabolic disorders and other medical conditions that can affect body odor. For example, in a disease called Trimethylaminuria (also known as fish-odor syndrome), the body cannot completely convert certain substances that then pass into sweat, urine or breath. This usually results in a fishy odor, but in some cases, a different, uncharacteristic marijuana-like smell may also result.