Side-by-side comparison
| Feature | Nit Happens | Nix | RID |
|---|---|---|---|
| Active ingredient | None (mechanical action) | Permethrin 1% | Pyrethrins 0.33% + PBO 4% |
| Mechanism | Physically disrupts lice and nit attachment | Insecticide (neurotoxin) | Insecticide (neurotoxin) |
| Cure rate — 1 treatment | 54% lice-free at Day 8¹ | 15–55% | 18–22% |
| Cure rate — up to 2 treatments | 89% ITT; 95.8% per-protocol¹ | 15–55% (resistance limits gains) | 18–22% (similar) |
| Pesticide-free | ✅ Yes | ❌ No | ❌ No |
| Resistance issue | None — physical mechanism | ⚠ 42+ U.S. states (CDC, 2025) | ⚠ Similar resistance pattern |
| Safe for eczema/sensitive skin | ✅ Preferred option | ⚠ Caution advised | ⚠ Caution advised |
| Age approval | Per label guidance | Ages 2+ | Ages 2+ |
| Available at Walgreens | ✅ Yes | ✅ Yes | ✅ Yes |
| Clinical study | IRB-approved (Villar & Rivera, 2020) | Multiple published trials | Multiple published trials |
Why do Nix and RID have such low cure rates?
Permethrin and pyrethrins are neurotoxins that worked well when they were introduced in the 1980s and 1990s. The problem: lice develop genetic resistance to neurotoxins over time through a mechanism called knockdown resistance (kdr). According to the CDC (2025), super lice — lice with genetic mutations that make them resistant to permethrin — have been identified in at least 42 of the 48 continental U.S. states.
In the most rigorous published clinical trial of permethrin (Burgess et al., BMC Dermatology, 2013), the cure rate was just 14.9% — meaning more than 85% of participants still had lice after a two-application course of Nix. Families who use them as directed and still find live lice a week later are not doing anything wrong. The lice have evolved past the treatment.
How is Nit Happens different?
Nit Happens uses a fundamentally different mechanism. There's no chemical active ingredient and no neurotoxin. The kit works in five steps:
- Apply the treatment gel to wet hair — loosens the bond between nits and the hair shaft
- 10-minute wait
- 15–30 minutes of thorough brushing with the applicator brush to physically remove lice and nits
- Second 10-minute wait
- Rinse and removal with the shampoo gel
Because the mechanism is physical — not chemical — lice cannot develop resistance to it. There are no pesticides and no synthetic chemicals that lice can evolve around. This is why Nit Happens' cure rates hold up in the real world, where Nix and RID's don't.
What about the comparison claim: "over 2x more effective"?
Based on the H.A.L.T. clinical study (Villar & Rivera, 2020), Nit Happens achieved an 89% intent-to-treat cure rate at Day 15. Compared to the median published cure rates for permethrin (Nix) and pyrethrins (RID) in modern resistant lice populations, this exceeds 2x more effective.¹
The most rigorous published clinical trial of permethrin (Burgess 2013) found a 14.9% intent-to-treat cure rate — approximately 6x lower than Nit Happens' 89%. Even against the mid-range permethrin estimates in Meinking et al. (2004–2010), which put permethrin cure rates at roughly 28–55%, Nit Happens' 89% represents more than 2x the effectiveness. This is not a head-to-head study.¹
Where to buy
Nit Happens is available at Walgreens locations nationwide and on Amazon. To find a store near you with the kit in stock tonight, see our Walgreens store locator guide.
The bottom line
Nix and RID are pesticide-based treatments with declining effectiveness due to widespread lice resistance across the U.S. In the most rigorous published trials, permethrin cure rates have fallen as low as 14.9%. Nit Happens, a pesticide-free mechanical-action kit, achieved an 89% cure rate in an IRB-approved clinical study — with no adverse events reported and no resistance possible.
Sources
- Villar ME, Rivera SR. H.A.L.T. Healthy Alternative Lice Treatment Study. IRB-approved by IntegReview IRB, Austin, TX. December 3, 2020.
- Burgess IF, Brunton ER, Burgess NA. BMC Dermatology. 2013;13:5.
- Meinking TL, et al. Pediatric Dermatology. 2004;21(6):670–674.
- Centers for Disease Control and Prevention. Parasites — Lice — Head Lice: Treatment. cdc.gov. Updated 2025.
- Gellatly KJ, et al. Journal of Medical Entomology. 2016;53(3):653–659.
- Pariser DM, et al. New England Journal of Medicine. 2012;367(18):1687–1693.
- Heukelbach J, et al. BMC Infectious Diseases. 2008;8:115.