Free tool
Free fungal acne (Malassezia) checker
Paste any cosmetic label and we'll flag the fatty acids, esters and polysorbates with C11–C24 chain lengths — the ones that can feed Malassezia yeast and trigger fungal acne (pityrosporum folliculitis).
Why use this tool
C11–C24 chain-length focus
We surface the fatty acids and esters most commonly cited in Malassezia research — the chain lengths the yeast actually metabolizes.
Esters & polysorbates flagged
Polysorbate 20/40/60/80 and other esters of fatty acids that can hydrolyze into problematic substrates are flagged with context.
Botanical oil context
Coconut, olive and other high-risk plant oils are flagged as caution tiers — not blanket bans — so you can weigh them with full information.
How it works
- 1
Copy the full ingredient list
Grab the INCI block from a retailer page or read it off the product. Commas matter — keep the exact order.
- 2
Run the fungal acne screen
Macherre applies Malassezia heuristics built from dermatology literature and surfaces every flagged ingredient with a risk tier.
- 3
Cross-check with related tools
If you're also congestion-prone, run the result through the pore-clogging checker — fungal acne and comedonal acne can coexist.
Example output
Illustrative preview — exact layout may vary slightly in the app.
Flagged (Malassezia context)
- Coconut oilRich C12–C14 fatty acid spectrum
- Polysorbate 60Ester surfactant — context-dependent
- SqualaneOften tolerated — verify individually
Fungal acne — clinically known as pityrosporum folliculitis or Malassezia folliculitis — looks like classic acne but isn't bacterial. It's driven by an overgrowth of Malassezia, a yeast that feeds on certain fatty acids and esters in the C11–C24 chain-length range. That's why dermatologist-aware routines avoid those ingredients in leave-on products: starve the yeast and the bumps usually settle.
Macherre's fungal acne checker scans any ingredient list for the substrates most consistently flagged in dermatology literature — fatty acids, esters, polysorbates that hydrolyze into them, and high-risk botanical oils. It's a fast first filter, not a diagnosis. Concentration, leave-on vs rinse-off use, your immune response and a real clinical assessment all still matter, so combine the screen with a dermatologist's input when you can.
Frequently asked questions
What is fungal acne, exactly?▼
Fungal acne is the casual name for pityrosporum (Malassezia) folliculitis — itchy, uniform small bumps caused by yeast overgrowth in the hair follicles, not by the bacteria that cause classic acne.
Does a flagged ingredient automatically mean a breakout?▼
No. Rinse-off cleansers contact skin briefly, while leave-on creams sit there for hours — risk depends on use, concentration and your individual tolerance. Treat flags as context, not absolutes.
Can I self-diagnose fungal acne with this tool?▼
The checker can support a suspicion, but a definitive diagnosis usually needs microscopy or a dermatologist's eye. If symptoms persist, get it confirmed clinically.
Does this replace antifungal treatment?▼
Not at all. Topical or oral antifungals (ketoconazole, ciclopirox, itraconazole) are how fungal acne is treated medically — the checker only helps you avoid feeding the yeast through your products.
Why does coconut oil flag so often?▼
Coconut oil is rich in C12 (lauric acid) and other medium-chain fatty acids that score high on Malassezia feeding models. That doesn't make it bad universally — just risky if you're prone to fungal acne.
How accurate are community “FA-safe” lists?▼
Crowdsourced lists are a useful supplement but they evolve and sometimes contradict the literature. Combine algorithmic checks like Macherre's with your own patch-test outcomes.
Ready to try it in the app?
Download Macherre for scans, shelves, comparisons, and routines tailored to your skin.
Sign up on the web from the same link if you prefer.