There is a moment — usually mid-commute, somewhere between the doors closing and the Tube gaining speed — when the thought strikes: is that me? It's a universal anxiety. And for years, the beauty industry answered it with the same blunt instrument: kill the bacteria, block the sweat, mask everything else with synthetic fragrance.
That approach, it turns out, may have been missing the point entirely.
Science has spent the last decade building a far more nuanced picture of what's actually happening under your arms — and the emerging consensus is genuinely fascinating. Your underarm skin hosts a thriving community of microorganisms. Some produce odour. Others actively suppress it. The relationship between them, and the products you use to intervene, is considerably more complex than "bacteria = bad."
What Exactly Is the Skin Microbiome?
The term "microbiome" has become something of a buzzword in wellness circles, but the science behind it is solid. Your skin is colonised by trillions of microorganisms — bacteria, fungi, viruses — that together form what researchers call the skin microbiome. Far from being something to scrub away, this microbial community plays an active role in your skin's health, its immune response, and yes, how it smells.
Different areas of the body host distinctly different microbial populations. The underarm — or axilla, to use the clinical term — is a particularly rich environment. It's warm, often occluded by clothing, and produces both eccrine sweat (the watery kind your body uses to cool down) and apocrine sweat, a thicker secretion linked specifically to the sweat glands in your armpits and groin. Apocrine sweat is actually odourless at the point of production. What creates body odour is the metabolic activity of bacteria breaking it down.
Here's where it gets interesting. Not all bacteria do this equally. A 2015 study published in the Journal of Investigative Dermatology found that Corynebacterium species — common underarm residents — are particularly efficient at producing thioalcohols, the sulphur-containing compounds responsible for that distinctive sharp odour. Staphylococci, by contrast, produce a milder, more acidic smell. And some bacteria produce relatively little odour at all.
The composition of your personal microbial community is one reason why body odour is so individual. Genetics, diet, hormones, stress levels, and — critically — the products you use all influence which bacteria thrive and which don't.
What Conventional Deodorants Actually Do
Most conventional deodorants and antiperspirants work through two main mechanisms: antimicrobial agents (typically alcohol or triclosan) that reduce bacterial populations, and aluminium salts (in antiperspirants) that temporarily block sweat ducts. Both approaches are effective in the short term. Neither is particularly selective.
When you apply a broad-spectrum antimicrobial to your underarm, you don't just suppress the odour-causing bacteria — you disrupt the entire community. Research from the University of California, San Diego, published in the journal PeerJ, found that regular antiperspirant use significantly altered the composition of the underarm microbiome, with some studies noting a rebound effect: stop using antiperspirant, and different bacterial populations — sometimes more odour-producing ones — can temporarily bloom as the ecosystem rebalances.
This is why many people who switch from conventional antiperspirant to a natural deodorant experience a transition period of one to three weeks during which their body odour seems, paradoxically, worse. The microbiome is recalibrating. It's not a sign that natural deodorant doesn't work — it's a sign that years of disruption are being undone. Understanding this makes the transition considerably easier to navigate.
The Case for a Microbiome-Friendly Approach
The latest thinking in deodorant science — and it is genuinely evolving — has shifted from "eliminate bacteria" to "work with your microbiome." Research published in a February 2026 cosmetic dermatology journal examined how prebiotic and postbiotic ingredients can selectively support beneficial skin bacteria whilst discouraging odour-producing strains. The London Dermatology Centre has also noted that microbiome therapies are now a mainstream area of dermatological research, with topical applications showing particular promise.
In practical terms, this means looking for deodorant formulas that:
- Avoid broad-spectrum antimicrobials that indiscriminately disrupt microbial balance
- Use ingredients with selective, gentle action — such as zinc oxide, which has well-documented antibacterial properties at low concentrations without sterilising the skin environment
- Support the skin's natural slightly-acidic pH, which itself discourages odour-producing bacteria
- Contain plant-based powders like arrowroot, which absorb moisture without blocking sweat ducts
It's also worth noting what the NHS has long advised: sweat itself is not the enemy. According to NHS guidance, sweating is a normal and necessary physiological process that regulates body temperature and supports skin health. The goal of a good deodorant should be to manage odour intelligently — not to eliminate the body's natural functions wholesale.
Natural Ingredients and the Underarm Microbiome
Plant-based deodorant formulas have sometimes been dismissed as less effective than their conventional counterparts. That reputation is increasingly outdated. Here's a closer look at the key natural ingredients and what the evidence says about them:
Zinc Oxide
Zinc oxide has a long history in dermatology — you'll find it in everything from nappy rash cream to mineral sunscreen. At the concentrations used in natural deodorants, it acts as a gentle antimicrobial, inhibiting odour-producing bacteria without the scorched-earth approach of alcohol-based formulas. It's also soothing, which makes it a good choice for sensitive underarm skin.
Arrowroot Powder
Arrowroot is a fine, starchy powder derived from the Maranta arundinacea plant. In deodorant formulas, it functions as an absorbent — drawing moisture away from the skin surface and helping the formula adhere evenly. It doesn't block sweat glands; it simply manages moisture at the surface. For people who want to feel drier without the aluminium-salt mechanism of antiperspirants, arrowroot is the key ingredient to look for.
Baking Soda (Sodium Bicarbonate)
Effective at neutralising odour through pH adjustment, baking soda is a common natural deodorant ingredient — but one that some people find irritating, particularly on sensitive or freshly shaved skin. Many better natural formulas now use lower concentrations or replace it entirely with alternatives. If you've had a reaction to a natural deodorant in the past, baking soda is the likely culprit.
Plant-Based Fragrance and Essential Oils
Fragrance is where natural deodorants can still trip up. Some essential oils, however natural their origin, are potential skin sensitisers — citrus oils in particular can cause photosensitivity. A fragrance-free or very lightly scented formula is generally the safest bet for underarm skin, which is already prone to sensitivity.
The Transition Period: What to Expect and How to Manage It
I remember the first time I switched to a natural deodorant properly — not just tried it for a day and given up, but genuinely committed to it. The first week was fine. Week two was less fine. By week ten, I couldn't imagine going back.
The transition period is real, and pretending otherwise doesn't help anyone. Here's a practical guide to getting through it:
- Expect two to four weeks of adjustment, particularly if you've used antiperspirant consistently for years. The microbiome shift takes time.
- Start during cooler weather if possible — lower temperatures mean less sweat production and a gentler transition.
- Wear breathable fabrics: natural fibres like cotton and linen allow air circulation, which helps manage both sweat and odour during the adjustment phase.
- Reapply as needed, especially in warmer months. Natural deodorant formulas work differently to antiperspirants — the expectation that one morning application will last through a full day regardless of activity isn't always realistic, and that's fine.
- Wash your applicator regularly. This is easy to forget but important — residue buildup on the applicator itself can reintroduce bacteria to fresh product.
One practical advantage of a refillable deodorant system — like the one Lifelong Deodorant uses — is that the applicator itself can be washed between refills, keeping everything genuinely hygienic. It's a small detail that makes a real difference over time.
Should You Bother? The Honest Answer
Let's be straightforward here. Conventional antiperspirants are effective. They've been used safely by billions of people for decades, and there is no credible scientific consensus linking them to serious health harm. If a conventional antiperspirant is working well for you and you have no particular reason to change, the decision is a personal one.
That said, there are genuine reasons to consider a gentler, more microbiome-conscious approach:
- Sensitive skin: Aluminium salts and synthetic fragrances are common underarm irritants. Many people with eczema, contact dermatitis, or post-shave sensitivity find natural formulas considerably more comfortable.
- Long-term microbiome health: The evidence is early, but the direction of travel in dermatological research suggests that preserving microbial diversity is better for skin health than indiscriminate disruption.
- Environmental impact: Every conventional deodorant stick is a single-use plastic container. The average person discards 12 or more per year. A refillable system — where the applicator itself is designed to last indefinitely and refills arrive in compostable packaging — removes that waste from the equation entirely.
- Cost over time: A quality refillable applicator costs more upfront. But when the applicator itself never needs replacing and refills cost less per use than repeatedly buying new sticks, the economics shift in your favour over time.
Getting the Transition Right
If you decide to make the switch, a few practical tips beyond the transition period advice above:
Look for a formula that suits your specific needs. Some people do well with an all-natural formula using zinc oxide and arrowroot. Others find they need a little more — and that's exactly why brands like Lifelong offer both a natural formula and an antiperspirant option. The point isn't to judge what you put on your body; it's to offer a more thoughtful choice regardless of what that choice is.
Pay attention to packaging. A formula that's better for your skin microbiome but arrives in layers of single-use plastic is solving one problem whilst creating another. The most coherent choice is a formula that's gentle on your skin, honest about its ingredients, and comes in packaging that doesn't generate unnecessary waste.
Refillable powder-based deodorants represent the current frontier here: the concentrated powder format cuts transport emissions dramatically, the compostable pouch leaves nothing to landfill, and the applicator — if it's well-made — lasts for years. That's a reasonable definition of a product that's earned its place in your bathroom.
The Bottom Line
Your underarm microbiome is not your enemy. It's a complex, dynamic ecosystem that's been shaped by your unique biology, your habits, and the products you've used for years. Treating it with a degree of respect — choosing formulas that work with it rather than against it — is both better skin science and, increasingly, better product science.
That said, the transition. It takes time. It takes a bit of patience. And it really is worth it.
The bacteria have been there all along. You might as well make friends with them.
