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Part of our Kerassentials overview. Last checked October 19, 2026.
Does Kerassentials work on toenail fungus? There is no published study of Kerassentials itself, so the honest answer is that it is unproven. The oil lists one amount on its label, undecylenic acid 5%, and nothing else is quantified.[1] The strongest nail trial on any of its ingredients used undiluted tea tree oil for six months, and 18% of people ended with a negative fungal culture.[3]
Does Kerassentials work? The short answer
We cannot say Kerassentials works, because the evidence that would show it does not exist yet. No randomized trial, no case series and no lab test of the finished oil has been published.
What we can say is narrower. Kerassentials is a brush-on oil sold through BuyGoods in a 0.5 oz (15 ml) bottle, labeled for external use only.[1] Its lead ingredient, undecylenic acid, beat placebo on athlete's foot skin in older trials, at concentrations of about 22% to 23%.[6] Kerassentials states 5%.
Nails are harder than skin. FDA lists any topical antifungal ingredient labeled for use on the nails as lacking the data needed for general recognition of safety and effectiveness.[5] So the ingredient story is plausible on paper and untested where it counts: on toenails, at this strength, in this blend.
Which evidence levels should you not confuse?
Sales pages often mix four different kinds of evidence. Only the last two tell you whether a product helps people, and Kerassentials has neither.
Plausibility
Lab dishes show that tea tree, clove, lemongrass and manuka oils slow fungi growing in a plate. That is the weakest rung. A nail plate is thick, and an oil that stops fungus in a dish may never reach the fungus under the nail.
Ingredient trials
Some ingredients have human trials, mostly on skin. Undecylenic acid powder gave 88% negative cultures against 17% for placebo in athlete's foot after four weeks.[6] That result is for skin, at a higher strength, in a different product.
Finished-product trial
This is a study of Kerassentials itself, with a control group, on people with lab-confirmed nail fungus. None has been published. The vendor says "tests have indicated that Kerassentials takes around 9-12 weeks to show results", but those tests are not public.[2]
Replication
A second independent trial confirming the first. With no first trial, there is nothing to repeat.
Kerassentials claims vs what the evidence supports
The vendor's statements below are quoted from its own pages. The right-hand columns show how far the published research goes.
| Vendor claim | Reasonable reading | Limitation |
|---|---|---|
| "3-Minute Shower Hack Flushes Away Fungus In Record Time" | A sales headline | No trial of the oil; FDA does not recognize any nonprescription nail antifungal[5] |
| Results in "around 9-12 weeks" | The vendor's estimate | Tests not published; a clear toenail takes a year or longer to grow out even on prescription pills[9] |
| "Doctor Formulated Blend" | A label badge | No doctor is named with full name or credentials |
| "Safe and effective" ingredient cards | Ingredient-level marketing | Only undecylenic acid has a stated dose, and 5% is below FDA's 10% to 25% skin range[4] |
| "No Chemicals" | Plant-oil positioning | The label lists mineral oil, isopropyl palmitate, menthol and camphor[1] |
If you still want to try it, buy from the vendor's own checkout, keep the packing slip, and note the 60-day refund window from delivery (checked October 19, 2026).
Which ingredients matter most?
Two ingredients carry almost all the evidence weight: undecylenic acid and tea tree oil. Both were studied at strengths that differ from what Kerassentials discloses, and mostly on skin.
- Undecylenic acid, 5%. FDA's skin monograph covers 10% to 25% total undecylenate.[4] In a lab test on human nail pieces, four nonprescription solutions with 25% undecylenic acid or 1% tolnaftate reached and slowed nail fungus far less than prescription efinaconazole.[7]
- Tea tree oil, amount undisclosed. The 1994 nail trial used 100% oil twice daily for six months with nail filing. Negative cultures were 18% against 11% for 1% clotrimazole, with no placebo group.[3] NCCIH says the research on nail fungus is too thin for conclusions.[11]
- Camphor and menthol, label B only. A small case series of a camphor and menthol rub, 18 people, no control group, reported 27.8% clearance at 48 weeks.[8]
The other oils (lavender, lemongrass, clove, manuka) have lab data only for fungus. The carrier oils, such as almond, flaxseed and jojoba, are there to spread the mix. Full details are on our Kerassentials ingredients page.
What results are realistic to expect?
Expect slow change at best, measured in months. Toenails grow slowly, and even prescription options take about a year for a clear nail to grow in.
The American Academy of Dermatology says prescription nail solutions such as efinaconazole 10% and tavaborole 5% are applied once a day, usually for 48 weeks.[9] MedlinePlus says medicines clear the fungus in about half of people, and it can come back.[10]
Against that baseline, the vendor's 9 to 12 week window is short. The vendor's own refund page advises using the oil "at least 3 months", which is longer than its 60-day refund window.[12] Plan for the long haul, and take photos every four weeks so you can judge for yourself. Our how to use Kerassentials guide covers the routine.
When should you see a doctor instead?
See a doctor before buying anything if you have not had the nail tested. AAD notes that psoriasis and nail injury can look the same as fungus, and a nail clipping or culture settles it.[9]
See a doctor right away if:
- the skin around the nail is red, hot, swollen, painful or leaking pus
- you have diabetes, poor circulation in your feet or a weakened immune system
- the nail lifts and bleeds, or a dark streak appears in the nail
- redness spreads up the toe or foot, or you have a fever
- a rash, blisters or burning start after you apply any nail oil
Evidence conclusion
Kerassentials is a plausible but untested nail oil. The table sums up where the evidence stands.
| Decision question | Current assessment |
|---|---|
| Has Kerassentials been tested on people? | No published trial found |
| Is the main active at a studied strength? | No: 5% stated vs 10% to 25% in FDA's skin monograph |
| Does any ingredient have nail data? | Tea tree oil, at 100%, with 18% negative cultures |
| Is the formula fully disclosed? | Ingredients yes, amounts no; two labels exist |
| Is there a refund? | 60 days from delivery, all bottles mailed back at your cost (checked October 19, 2026) |
Read our Kerassentials side effects page before you start.
Back to the Kerassentials overview.
Frequently asked questions
How long does Kerassentials take to work?
The vendor says its unpublished tests point to 9 to 12 weeks. Dermatologists say a clear toenail takes a year or longer to grow in, even with prescription medicine, so any change from a nail oil would be slow.
Is Kerassentials effective for toenail fungus?
There is no published trial of Kerassentials, so its effect is unknown. Its main active, undecylenic acid, is listed at 5%, below the 10% to 25% FDA range for skin, and no OTC antifungal is recognized for nails.
What is Kerassentials used for?
The vendor sells Kerassentials as a brush-on oil for nails and the skin around them, aimed at people with nail fungus. It comes in a 0.5 oz bottle, is for external use only, and is applied four times a day.
Are there Kerassentials results photos I can trust?
The vendor shows month 1, month 3 and month 6 nail photos with no names, dates or study behind them. Read them as advertising. Your own photos taken every four weeks are a better guide.
Does tea tree oil help nail fungus?
One 1994 trial of 100% tea tree oil on toenails for six months found 18% negative cultures, against 11% for clotrimazole, with no placebo group. NCCIH says research is too limited for firm conclusions.
Sources
- Kerassentials product label (image A). Kerassentials vendor site, read October 19, 2026.
- Contact us and FAQ. Kerassentials vendor site, read October 19, 2026.
- Tea tree oil vs clotrimazole for toenail onychomycosis, randomized trial (1994). PubMed, read October 19, 2026.
- 21 CFR 333.210, antifungal active ingredients. eCFR, read October 19, 2026.
- 21 CFR 310.545, drug products containing certain active ingredients. eCFR, read October 19, 2026.
- Undecylenic acid and zinc undecylenate powder in tinea pedis, placebo-controlled trial (1980). PubMed, read October 19, 2026.
- Ex vivo nail penetration of OTC antifungal solutions vs efinaconazole. PubMed, read October 19, 2026.
- Mentholated ointment for onychomycosis, case series. PubMed, read October 19, 2026.
- Nail fungus: diagnosis and options. American Academy of Dermatology, read October 19, 2026.
- Nail fungus. MedlinePlus, US National Library of Medicine, read October 19, 2026.
- Tea tree oil. NCCIH, read October 19, 2026.
- Refund policy. Kerassentials vendor site, read October 19, 2026.
This page is general information, not medical advice. Dietary supplements are not reviewed by the FDA for safety or effectiveness before they are sold and are not intended to diagnose, treat, cure or prevent any disease. Talk to your doctor before taking any supplement, especially if you are pregnant, nursing, take medication or have a health condition.
