ArcherZyme® clinical study published in JEADV Clinical Practice

Odour is a bacteria problem, not a sweat problem

Underarm odour is produced mostly by bacteria that break down odourless compounds in apocrine sweat. Most published work supports a major role for Staphylococcus hominis, alongside some Corynebacterium species.

Conventional deodorants commonly rely on antiseptics, which act on the whole skin community rather than on the bacteria responsible. We designed ArcherZyme®, a phage-derived enzyme known as a lysin, to act selectively on S. hominis and leave the rest of the community in place.

The study at a glance

The trial tested ArcherZyme® on its own, in a simple solution, against a control on the other underarm of the same person.

What the sniffer panel found

Two hours after one supervised application, the mean odour score on the treated underarm had fallen by 60.7%, from 7.07 to 2.78 on the 0–10 scale, far more than any change on the untreated underarm. At 24 hours the treated side was still 42.6% lower, while the untreated side had risen by 5.1%. The paper reports minimal variation between participants.

Tested for skin safety

Before the trial, ArcherZyme® went through two standard safety checks. The first, OECD 439, is an internationally recognised laboratory test that uses a reconstructed model of human skin to check whether an ingredient causes irritation, with no testing on people or animals. ArcherZyme® was classed as non-irritant.

The second was a patch test on human volunteers, following the Indian Standard for cosmetic safety evaluation (IS 4011:2018). The ingredient is held against the skin and the site checked for any reaction. During the trial, the treated skin was examined again for signs of irritation, and no skin reactions were observed.

What participants reported

Participants completed a questionnaire during the week of home use:

• 2 to 6 hours. 100% of participants agreed ArcherZyme® was effective at controlling odour for 2–6 hours.
• 6 to 12 hours. 66.7% agreed it controlled odour for 6–12 hours.
• Beyond 12 hours. None felt it was effective beyond 12 hours, although the paper notes that the sniffer-panel scores suggest otherwise.

The gap participants described

Everyone in the study was a regular deodorant user, so they came with clear expectations. In the questionnaire, 25 of the 27 participants said no product they had used before gave satisfactory odour control beyond six hours after application. Against that benchmark, 66.7% agreed that ArcherZyme® controlled odour for 6 to 12 hours, from a simple test solution applied once a day rather than a finished deodorant.

These are participants’ own impressions, not a head-to-head test against other products. They still point to a real opportunity for formulators: longer-lasting odour control from an active that acts preferentially on the bacterium behind odour.

Odour down, diversity preserved

Consistent with our laboratory data, ArcherZyme® affected S. epidermidis, a common beneficial skin bacterium, less than it affected S. hominis. At 24 hours the ratio of S. hominis to S. epidermidis on the treated side had fallen from 6.7 to 3.6, which suggests that S. epidermidis may recover faster.

Cutibacteria and Corynebacteria showed no significant change, which the authors read as a sign that overall microbiome diversity was not affected.

New evidence in an old debate

Scientists have long debated which underarm bacteria matter most for body odour. Staphylococcus hominis is widely implicated, but some Corynebacterium species have also been put forward as major contributors. One detail points towards S. hominis: it is one of only two staphylococci, with S. haemolyticus, that carry the enzyme turning odourless compounds in sweat into thioalcohols, the sulphur-containing molecules behind body odour. Corynebacteria do not carry it.

Our study adds clinical evidence to that debate. ArcherZyme® acts preferentially on S. hominis and had no significant effect on Corynebacteria, yet odour scores fell by a mean 60.7% at the first reading, two hours after application. The authors conclude that the speed and size of that reduction strongly suggest S. hominis is a major driver of underarm odour, a finding they believe may contribute to that long-standing debate.

The people who made it happen

• Authors. Maurice van Steensel, co-founder; Fabian Hia and Beh Mei Zhen, from the R&D team; and Boon Chong Goh, founder and CTO.
• Expecto Health Sciences. Managed the logistics around our clinical trial.
• Sequential. Conducted the bacterial load assessments for our microbiome analysis.

Why this matters for your next launch

In November 2025, ArcherZyme® received the Gold Award in the Actives category at in-cosmetics Asia 2025. This study is the clinical dataset behind that entry.

If you develop deodorants or body-care products, our paper gives your technical and regulatory teams the complete methods, statistics and limitations to assess for themselves.