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.

 

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Primary Cutaneous Tolerance on Healthy Participants by Single 48-hr Patch Test

Final Report – Study No. 20H-0224-34
February 28th, 2020

Study Sponsor:
Arbor Development
Represented by Michael Hatten – President
P.O. Box 65188, West Des Moines, Iowa, 50265, USA
Tel: 515-979-1282

Study Investigator:
Represented by Elisabeth Fiquet, Investigator
5475 Paré, Suite 206, Mont-Royal, Quebec, H4P 1P7, Canada
Tel: 514-343-0001

This final report was prepared by a clinical testing laboratory with quality management system registered to ISO 9001. This report is composed of 10 pages including appendices (2 pages).

SUMMARY – Single 48-hr Patch Test, Study 20H-0224-34

Sponsor Code: LG

Test: Study of a cream for Primary Cutaneous Tolerance (irritation potential) tested on 25 healthy participants with a single 48-hr patch application.

Product: Lice Shredder
Customer Lot#: LS123019
Evalulab Lot#: 200116.LG.01

Date: February 27th, 2020

Results: Under the conditions of the test procedure referenced herein, and based on the results presented in this report, the test product referenced above has produced no signs of primary cutaneous irritation or intolerance. Hence, the test product may be considered as non-irritant. Also, given the control provided by a dermatologist, the test product may bear the claim "Tested under the control of a dermatologist".

STUDY OBJECTIVE

To determine the primary cutaneous tolerance to a cream and to determine the existence of an allergic pre-disposition on 25 healthy participants with a single 48-hour patch application.

PROTOCOL

1. Ethics Committee

This standard procedure and associated documents were reviewed and approved prior to the commencement of the study, by an Ethics Committee (an independent organization whose responsibility is to ensure the protection of the rights, safety and well-being of the subjects participating in the study).

2. Duration

The study took place from February 24th to February 26th, 2020.

3. Investigation Site

Evalulab Inc. located at 5475 rue Paré, Suite 206, Mont-Royal, Quebec, H4P 1P7, Canada.

4. Personnel

This study was conducted by Evalulab Inc., represented by Rébecca Padey, M.A. – Laboratory Assistant, under the supervision of Elisabeth Fiquet, M. Sc. – Investigator and under the control of Doctor Michel Journet, MD Dermatologist.

5. Test Product

Upon reception, the test product was registered in the "Receptions Book" and assigned a code, followed by its storage at ambient humidity and temperature in its original container (as received) in an area allocated for this purpose. Two (2) units of 100g were received.

Description of the test product:
Product name: Lice Shredder
Category: Cream
Customer Lot#: LS123019
Evalulab Lot#: 200116.LG.01

Description of control: Pure Vaseline USP.

Application: The product was diluted at 10% and was generously applied on the entire surface of the patch. The total area of application is about 2.25 cm².

6. Material

The patches used in this study were TruMed® semi-occlusive, cotton "BBA149-129 Absorbent" with "3M 1530 Tape" adhesive backing.

7. Quality Assurance

Good Clinical Practice (GCP) is defined by the totality of the pronouncements put in place for ensuring the quality and authenticity of the trials and the obtained data on one hand and the respect for the ethics on the other.

The data obtained for each participant is recorded in individual Case Report Forms. The data entry is made in black ink. In case of errors or omissions, the initial entry is crossed out and initialed by the investigator.

All recorded data is validated by the investigator, who assumes responsibility for the quality of the work presented and verifies that all gathered data is in agreement with the protocol.

The records obtained during the study will be kept by Evalulab Inc. for a period of 2 years.

8. Adverse Events or Severe Adverse Events

An "Adverse Event" is defined as any noxious and unintended response observed in a participant testing a product that does not necessarily have a causal relation with the test product in question.

The risks for adverse events associated with this test may vary amongst the participants. Participants may be subject to rash (intense redness), stinging and burning sensations, cracking, exfoliation effect, dryness or even pain if the test product is strongly irritant or if the participant is particularly sensitive to the product. Participants may also develop an allergic sensitization to the test product or to its components.

The term "Serious Adverse Event" refers to any untoward medical occurrence, related or not to the test product that may lead to death, persistent or significant disability, that requires hospitalization or prolongation of a hospitalization period or that provokes invalidity, significant or permanent incapacity, or that translates to congenital anomaly or malformation.

The participants were instructed to immediately communicate any reactions to Evalulab.

No "Severe Adverse Event" occurred during the entire length of the study.

9. Data Analysis

The tolerance to the product was evaluated by a laboratory technician (trained by a dermatologist) - considering the scores, observed reactions, the level of intensity and the reproducibility from one participant to another. The individual results are presented in the Appendices – Table II.

10. Amendments to Protocol

There were no amendments to the protocol.

11. Primary Cutaneous Tolerance Test

Type of Study

Monocentric and open-ended, meaning the evaluator, participants, and sponsors alike, were aware of the nature of the test material.

Participants

Recruitment of participants: A total of 27 participants were recruited based on the inclusion and exclusion criteria. The profile of each participant is presented in Table I in the Appendices.

Subject Demographics

Sex	Number	Age	Average Age
Male	7	18 to 63	43.43
Female	20	19 to 79	49.40
Total	27	18 to 79	47.85

Informed Consent Form: All participants had to sign and date the Informed Consent Forms explaining the conditions of the test, the risks involved and briefly describing the product to be tested. Each participant was informed verbally and in writing about the nature of the test and of the potential risks involved.

Confidentiality: Participation of the subjects in this study is confidential. The information gathered in the course of the study was recorded in individual case report forms, that are numerically coded and do not contain the names of the participants. Only the employees of Evalulab, auditors of the sponsor, and regulatory bodies (FDA, Health Canada and the Ethics Committee) may have access to the confidential information.

Inclusion Criteria

1. Participants of the feminine or masculine sex, aged 18 years or older
2. With phototype I to IV according to Fitzpatrick's classification (very clear to mat) and with a skin type that does not interfere with the assessment of cutaneous reactions
3. Healthy and without any dermal anomalies on the areas to be tested
4. With no excessive body hair, especially on the test area
5. Who will cooperate and be present for a follow-up at every visit, informed and sensitized about the duration and the importance of controls allowing for a complete compliance with the study protocol
6. Who have read, signed and dated the Informed Consent Forms upon full knowledge of the risks involved with the study
7. Women who use a method of contraception (oral contraceptive, condoms, spermicidal creams, an intra-uterine device (IUD), abstinence…) or are in a menopausal status

Exclusion Criteria

1. Participants with a history of skin irritation or allergies to the type of product to be tested or in general, to glues (sticking plaster), with allergies to certain foods, to certain chemical products, to jewellery…
2. With a serious illness, health problem or chronic or progressive disease (asthma, diabetes, cancer, immunological deficiency, ablated organ…)
3. With a history of eczema, dermatitis, psoriasis or significant dermal anomalies on the test area
4. On medication or having taken medication in the last 7 days prior to the study that could affect skin characteristics or could bias the study (antibiotics, anti-inflammatory drugs, steroids, antihistamines…)
5. Who frequent tanning salons or foresee exposure to the sun
6. Who abuse alcohol, drugs or/and tobacco
7. Women who are pregnant, breastfeeding or expecting to become pregnant during the study

Design of the Study

Procedure: Prior to application of the patches, the test area (upper back, between the two shoulder blades) was carefully examined and wiped with alcohol if necessary (oily skin only). A patch containing the test product and another containing the negative control were applied to the test area, and were left in contact with the skin for 48 hours. Care was taken when positioning the patches to minimize the possibility of displacement or rubbing. The participants were not to remove or wet the patches and were to keep them covered with clothing and to avoid exposure to sun or other sources of tanning. The use of any other topical pharmaceutical or cosmetic products was not permitted during the study.

Observation and Data Collection: Forty-eight (48) hours after application, the patches were removed and all observations were recorded. In addition to the observations made and recorded by Evalulab, the participants were encouraged to observe and report to Evalulab any immediate or delayed reactions such as redness, irritation, itching, or other sensations on the application sites for up to 72 hours after application.

The test area and its surrounding area were observed for erythema, oedema, vesicles, blisters, ulcerations, dryness and acne (papules). These parameters were evaluated and graded as follows:

Reaction Scale:
0 = No visible reaction
+ = Erythema barely noticeable
1 = Mild / slight erythema in the patch zone
2 = Moderate but well defined erythema and presence of slight or barely visible oedema
3 = Marked erythema, presence of oedema and vesicles
4 = Severe erythema, presence of vesicles, blisters, and ulcerations

All observations and comments provided by the participants were recorded in their respective Case Report Form. The obtained scores were then entered in a tabular form showing the number of reactions after treatment.

RESULTS

Twenty-seven (27) participants, men & women from 18 to 79 years of age (Average Age = 47.85), were recruited and completed this study. The data obtained during the study is presented in Table II in the Appendices.

No pertinent reaction to the test product was observed during the study. Similarly, no reaction with the control (Vaseline USP) was observed.

CONCLUSION

Under the conditions of the study described herein, and based on the results obtained, the test product "Lice Shredder" has produced no signs of cutaneous irritation, it is therefore considered as non-irritant.

However, this test procedure does not allow for evaluation of the sensitization potential of the test product.

Finally, given the control provided by a dermatologist, the test product may bear the claim "Tested under the control of a dermatologist".

Rébecca Padey, M.A. – Laboratory Assistant | Date: Mont-Royal – February 28th, 2020
Elisabeth Fiquet, M. Sc. – Investigator | Date: Mont-Royal – February 28th, 2020
Marilou Nadeau, B. Sc. – Quality Assurance Director | Date: Mont-Royal – February 28th, 2020

APPENDICES

Table I: Participants' Profile 20H-0224-34

Participant #			Initials	Age	Sex
01	-0224-	001	HZ	47	F
02	-0224-	002	DT	63	M
01	-0224-	003	AM	49	F
01	-0224-	004	MP	46	F
01	-0224-	005	AA	43	F
01	-0224-	006	GS	46	F
01	-0224-	007	JP	37	F
01	-0224-	008	LC	42	F
01	-0224-	009	MA	77	F
01	-0224-	010	CP	74	F
01	-0224-	011	JB	79	F
01	-0224-	012	CL	60	F
02	-0224-	013	JJ	36	M
01	-0224-	014	MM	19	F
01	-0224-	015	JG	33	F
02	-0224-	016	CS	40	M
02	-0224-	017	LA	42	M
01	-0224-	018	CM	50	F
02	-0224-	019	PL	58	M
01	-0224-	020	CT	37	F
01	-0224-	021	ST	40	F
01	-0224-	022	SB	62	F
01	-0224-	023	NR	38	F
02	-0224-	024	CM	47	M
01	-0224-	025	RC	47	F
02	-0224-	026	CM	18	M
01	-0224-	027	SY	62	F

Table II: Individual Results of 48-Hour Patch-Test 20H-0224-34

No.			Initials	Sex	48h	72h*
01	-0224-	001	HZ	F	0	-
02	-0224-	002	DT	M	0	-
01	-0224-	003	AM	F	0	-
01	-0224-	004	MP	F	0	-
01	-0224-	005	AA	F	0	-
01	-0224-	006	GS	F	0	-
01	-0224-	007	JP	F	0	-
01	-0224-	008	LC	F	0	-
01	-0224-	009	MA	F	0	-
01	-0224-	010	CP	F	0	-
01	-0224-	011	JB	F	0	-
01	-0224-	012	CL	F	0	-
02	-0224-	013	JJ	M	0	-
01	-0224-	014	MM	F	0	-
01	-0224-	015	JG	F	0	-
02	-0224-	016	CS	M	0	-
02	-0224-	017	LA	M	0	-
01	-0224-	018	CM	F	0	-
02	-0224-	019	PL	M	0	-
01	-0224-	020	CT	F	0	-
01	-0224-	021	ST	F	0	-
01	-0224-	022	SB	F	0	-
01	-0224-	023	NR	F	0	-
02	-0224-	024	CM	M	0	-
01	-0224-	025	RC	F	0	-
02	-0224-	026	CM	M	0	-
01	-0224-	027	SY	F	0	-

* Optional    0 = No visible reaction

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