The Layer of Hygiene
Nobody Taught You

Let me tell you about one of the most common patterns readers describe to us. Someone has already talked to their dermatologist or primary care doctor, and tells us they've tried everything. Clinical-strength deodorants. Prescription antiperspirants. Chlorhexidine body washes. Probiotic soaps. Some have spent hundreds of dollars on products designed to mask, neutralize, or eliminate body odor from the outside.

And every time, I have to tell them the same thing: they've been treating the exit point while leaving the internal side mostly unexamined.

The persistent, systemic kind of body odor (the kind that doesn't fully resolve with external hygiene) is increasingly understood to originate in the gut. The volatile compounds responsible for that smell aren't produced on your skin. They're produced in your digestive tract, absorbed into your bloodstream, and expelled through your pores, breath, and sweat.

That's the concept behind internal hygiene, and it's the missing layer most people have never heard of.

When you eat protein-rich foods (meat, eggs, fish, dairy, legumes), your gut bacteria break them down through a process called putrefactive fermentation. Totally normal. Part of healthy digestion. But it produces byproducts.

The main culprits:

• Trimethylamine (TMA): produced when gut bacteria metabolize choline and carnitine. Responsible for a persistent, fishy body odor.
• Hydrogen sulfide (H₂S): the classic "rotten egg" smell. Produced during sulfur amino acid metabolism.
• Indole and skatole: breakdown products of tryptophan. Contribute to fecal-adjacent body odors.
• Volatile sulfur compounds (VSCs): a family of gases responsible for halitosis that doesn't respond to mouthwash alone.

These compounds don't stay put. They cross the intestinal barrier into your bloodstream and eventually exit through every available surface your body has.

Why Deodorant Can't Fix a Gut Problem

Think about what deodorant actually does: it either masks odor with fragrance or kills bacteria on the skin that interact with sweat. Antiperspirants go a step further by blocking sweat glands with aluminum compounds.

But if the odor-causing compounds are being delivered to your skin through your blood, no topical product can address the upstream side. You're treating the symptom at its most downstream point. It's like mopping a floor while the faucet is still running.

Readers often describe a wider odor pattern where the smell isn't limited to armpits but seems to come from the chest, back, scalp, or even the face. That pattern is a useful clue that the routine may need an internal layer, not only another surface product.

"When someone says they smell despite meticulous hygiene, the useful question is not whether they are clean enough. It is whether the routine is missing an internal layer."

What the Research Shows

The connection between gut metabolites and body odor isn't new to medical research. Clinical odor conditions helped researchers understand that compounds made in the gut can travel through the body and show up externally.

Most readers are not dealing with a rare diagnosis. The more common pattern is simpler: diet, transit time, and individual body chemistry can influence how many odor-related compounds build up before they leave the body. That can matter especially for people with:

• High-protein diets
• Gut dysbiosis (bacterial imbalance)
• Normal variation in how the body processes odor-related compounds
• Regular consumption of choline-rich foods (eggs, red meat, certain fish)
• Chronic constipation or slow intestinal transit

In these cases, the gut is producing more volatile compounds than the body can neutralize. The overflow exits through the skin.

The Bottom Line

Internal hygiene isn't a fad or a marketing buzzword. It's a straightforward application of gastroenterology principles that have been understood for decades but somehow never made it into mainstream hygiene culture.

We teach kids to wash their hands, brush their teeth, and bathe regularly. Those habits are essential. But they only cover two out of three layers. The third layer, addressing the volatile compounds produced inside the body during normal digestion, is the piece most people have never been told about.

Diet, supplementation, or both may help. But the first real step is just acknowledging that body odor has an internal component. Once you see that, you can choose tools that match the layer you are trying to address.

Refresh is one of the better formulas I've come across for this specific routine. If you've been struggling with persistent odor despite solid external hygiene, it's worth reviewing closely.