Clinical Evidence

For the mom nerds, the skeptics, the school nurses, the dermatologists, and anyone else who wants the actual data behind the claims on the box. Two independent clinical studies. Full results below. Nothing hidden.

The headline

Nit Happens is the all-natural lice treatment kit clinically proven 89% effective in eliminating head lice when used according to label instructions.¹ When families followed the full two-treatment protocol, that figure rose to 95.8%.¹

It's also independently verified as non-irritant under dermatologist control in a separate cutaneous tolerance study.⁵

Both studies are IRB- or ethics-committee-approved. Both are independent of Cartwheel. Both used the product exactly as it's sold today.

Study One: The efficacy trial

What it tested

Whether the Nit Happens Complete Lice Treatment Kit physically eliminates head lice and their eggs in real families dealing with active infestations — using only the kit, only the label instructions, only the components in the box.

Who ran it

Maria Elena Villar and Susan Rubio Rivera, independent investigators. The study was approved by IntegReview IRB (Austin, TX), an independent institutional review board that oversees clinical research ethics.

Who participated

• 26 people with active head lice infestations
• 23 children (88% of participants) ages 3 to 17
• 3 adults (12% of participants) ages 18+
• Mix of hair types: 96% fine hair, 65% straight, 27% wavy, 8% curly
• Mix of hair lengths: short, medium, and long
• All participants were screened to have at least three live lice before being enrolled
• Anyone who had used another lice treatment in the previous two weeks was excluded

What they did

The protocol followed the label directions exactly:

1. Day 1: Apply Treatment Gel to wet hair. Wait 10 minutes. Brush vigorously with the applicator (15-30 minutes depending on hair length). Wait another 10 minutes. Wash out with Removal Shampoo. Rinse.
2. Day 8 (one week later): Check for live lice. If clear, the protocol is complete. If lice remained, apply a second treatment using the same procedure.
3. Day 15 (two weeks later): Final check for live lice. Anyone still with live lice was provided a rescue treatment (Nix) and removed from the success count.

Average application time: 47.5 minutes for the first treatment, 50 minutes for the second.

The results, in plain English

After one treatment (Day 8): 54% of participants — 14 out of 26 — were completely lice-free and nit-free.¹

The remaining 14 participants received a second treatment that day.

After the full protocol (Day 15): 89% of participants — 23 out of 26 — were lice-free.¹

Of the three participants who weren't lice-free at Day 15, the investigators determined that two were re-infestations — they had been confirmed lice-free at Day 8, then caught lice again from someone in their household before the final check. That's not a treatment failure; that's the dishearteningly common reality of how lice spread in families.

When we exclude those two re-infestation cases, the per-protocol efficacy is 95.8%.¹

The full breakdown

Outcome	Participants	Percentage
Lice-free after one treatment (Day 8)	14 of 26	54%
Lice-free after full protocol (Day 15)	23 of 26	89%
Re-infestation (excluded from efficacy)	2 of 26	7%
True treatment failure	1 of 26	4%
Per-protocol efficacy (excluding re-infestation)	23 of 24	95.8%

What didn't happen

Zero adverse events were reported across the entire study. No skin reactions, no allergic responses, no scalp irritation. Children — including the youngest participants at age 3 — tolerated the extended brushing protocol without difficulty.

Study Two: The dermatologist-tested safety study

Effectiveness is one half of the story. Whether something is safe to put on a kid's scalp is the other half.

What it tested

Whether the Nit Happens formula causes any cutaneous (skin) irritation under sustained skin contact.

Who ran it

Evalulab, a clinical testing laboratory in Quebec, Canada, with a quality management system registered to ISO 9001. The study was conducted under the control of a dermatologist, Dr. Michel Journet, M.D., F.R.C.P.(C). Approved by an independent ethics committee prior to commencement.

Who participated

27 healthy adults, ages 18 to 79, both men and women.

What they did

Each participant had two patches applied to their upper back: one containing the Nit Happens test product, one containing a negative control (Vaseline USP). The patches stayed on for 48 hours of continuous skin contact. Participants couldn't remove or wet the patches, couldn't use any other topical products, and couldn't apply heat or sunlight to the test area.

After 48 hours, the patches were removed and the test areas were examined for any sign of reaction — redness, swelling, blisters, ulcerations, dryness, or acne. Participants were also asked to report any sensations like itching for up to 72 hours after removal.

The results

Zero reactions. Across all 27 participants. On either the test product or the control.

Every single participant scored 0 (no visible reaction) on the standard erythema/oedema/blister rating scale.⁵

The conclusion

From the final report, verbatim: "The test product has produced no signs of cutaneous irritation; it is therefore considered as non-irritant."

The study also earns Nit Happens the right to bear the claim "Tested under the control of a dermatologist."

How Nit Happens compares to the alternatives

The HALT study didn't directly test Nit Happens head-to-head against Nix, RID, ivermectin, or dimethicone-based products. What it gives us is a comparable cure-rate methodology — same endpoint (Day 14/15 lice-free status), same outcome measure (cure under label-directed protocol), same kind of pediatric-skewing population.

Compared against the published cure rates for the alternatives that are most commonly reached for first:

• Over 2x more effective than leading pyrethrin lice treatments (Nix, RID).²
• Up to 25% more effective than prescription-strength ivermectin (Sklice).³
• Up to 25% more effective than leading silicone-based suffocation treatments (Vamousse, LiceMD).⁴

And drug-free. No prescription. No neurotoxin. No pharmaceutical residue.

Why the mechanism matters

Most pesticide-based lice treatments work by chemically neutralizing lice. The problem isn't safety in the way most parents assume — it's that head lice in the U.S. have developed widespread resistance to those chemicals. A 2014 study published in the Journal of Medical Entomology documented permethrin/pyrethroid resistance in roughly 98% of U.S. head lice populations.²

Nit Happens doesn't try to chemically out-compete a population that's evolved resistance. Instead, it works through mechanical action — food-grade diatomaceous earth and walnut shell act as mild abrasives that physically damage the lice exoskeleton, while the applicator brush dislodges nits from the hair shaft. There's nothing for the lice to develop resistance to.

This is what makes the formula effective against "super lice" — the term parents and journalists use for permethrin-resistant strains.

What's in the formula

Treatment Gel: coconut oil, diatomaceous earth (food-grade), walnut shell, essential oils. Removal Shampoo: equally clean ingredient profile.

What's not in it: pesticides, neurotoxins, silicones, parabens, phthalates, preservatives, GMOs, or any pharmaceutical active. Vegan formulation. Cruelty-free.

Got more questions?

The full clinical reports are available on request. Email clinical@gocartwheel.com and we'll send them over.

If you're a school nurse, healthcare provider, or researcher, we can also provide additional methodology details, raw data summaries, and references to the comparative literature cited in our footnotes.