What is cocamide DEA lotion, and how does it aim to treat head lice?

Cocamide diethanolamine (cocamide DEA) lotion is a surfactant-based treatment designed to eliminate head lice. Cocamide DEA, commonly found in shampoos, acts by dissolving the waterproofing lipids that protect the lice, leading to dehydration and death. The idea is that this action disrupts the lice's outer layer, causing them to dry out and die.

How was the effectiveness of cocamide DEA lotion evaluated in studies?

The effectiveness of cocamide DEA lotion was assessed through a multi-stage approach. This included in vitro (laboratory) tests to observe its impact on lice and eggs, mimicking real-life application. These tests examined both its pediculicidal (lice-killing) and ovicidal (egg-killing) effects. The research further proceeded with two randomized, controlled clinical trials. In these trials, participants with head lice were divided into groups to test different application methods and compare the results.

What were the main findings of the clinical trials regarding cocamide DEA lotion?

The clinical trials revealed limitations in cocamide DEA lotion's effectiveness. Despite laboratory promise, the lotion, even when concentrated, did not consistently eliminate head lice infestations. The study compared different application methods, including single and multiple applications of 10% cocamide DEA lotion, and a comparison with 1% permethrin creme rinse. The trials found that cocamide DEA did not provide a sufficient solution for treating head lice in most cases, indicating that cocamide DEA alone may not be effective.

What were the methods used in Clinical Study 1 and Clinical Study 2?

Clinical Study 1 involved a single 60-minute application of 10% cocamide DEA lotion, followed by shampooing. Some participants were treated with 1% permethrin creme rinse for comparison. Clinical Study 2 compared two regimens of 10% cocamide DEA lotion: a single overnight application versus two 2-hour applications spaced one week apart. Hair drying was used to concentrate the lotion in this study.

Why is it important to consider alternative treatments for head lice, and what are the implications of these findings?

The search for alternative treatments is crucial because of insecticide resistance. The findings of the study suggest that relying solely on cocamide DEA lotion may not be effective for treating head lice, prompting the need for more effective treatments. This means that people may need to consider treatments that incorporate other active ingredients or methods to successfully eliminate lice infestations. Further research is needed to find the most effective and safe solutions for head lice treatment.

Microscopic view of lice being washed away with shampoo.

Head Lice Treatment: Why Cocamide DEA Lotion Falls Short

Beau Callahan in Health & Wellness December 2025 • 4 min read.

"A candid look at cocamide diethanolamine lotion's limited success in eliminating head lice, based on laboratory and clinical trials."

Head lice infestations are a common nuisance, particularly among school-aged children. While numerous treatments are available, the effectiveness of some products has been challenged by insecticide resistance. This situation has prompted the search for alternative solutions, including treatments based on surfactants, which work by disrupting the lice's outer layer, leading to dehydration.

One such surfactant-based treatment is cocamide diethanolamine (cocamide DEA) lotion. Cocamide DEA is a chemical commonly found in shampoos, valued for its ability to create foam and remove oils. The idea behind its use as a lice treatment is that it can dissolve the waterproofing lipids protecting the louse, ultimately causing dehydration and death.

However, a study published in PeerJ investigated the actual effectiveness of cocamide DEA lotion in eliminating head lice. The study combined laboratory tests with two clinical trials to assess how well the lotion performed in real-world conditions. The results, as we will explore, revealed the limitations of this approach.

How Was the Cocamide DEA Lotion Tested?

Microscopic view of lice being washed away with shampoo.

The study employed a multi-stage approach, starting with in vitro (laboratory) tests to understand how cocamide DEA affected lice and their eggs. These tests mimicked real-life application, helping researchers predict how the lotion would perform on actual infestations. The laboratory tests were followed by two randomized, controlled clinical trials within communities.

In the lab, lice and louse eggs were exposed to cocamide DEA lotion. Researchers watched closely to see if the lotion killed the lice (pediculicidal effect) and prevented eggs from hatching (ovicidal effect). The clinical trials involved children and adults with confirmed head lice. These participants were divided into groups receiving different treatments:

Clinical Study 1: Participants received a single application of 10% cocamide DEA lotion for 60 minutes, followed by shampooing. Some were treated with 1% permethrin creme rinse, a common insecticide.
Clinical Study 2: Compared two regimens of 10% cocamide DEA lotion: a single overnight application versus two 2-hour applications one week apart, each followed by shampooing. Hair drying was used to concentrate the lotion.

Researchers evaluated the success of each treatment by checking for the presence of live lice over a period of two weeks. They also tracked any adverse events or side effects reported by the participants. The goal was to determine if cocamide DEA lotion could effectively eliminate lice infestations and whether it was a safe and tolerable treatment option.

What Does This Mean for Head Lice Treatment?

While cocamide DEA showed some initial promise in laboratory tests, the clinical trials revealed its limitations. The lotion, even when concentrated through hair drying, did not effectively eliminate head lice infestations in most cases. This suggests that relying solely on cocamide DEA as an active ingredient may not be a sufficient solution for treating head lice.