Does Rid Have Ivermectin? A Look at Lice Treatment Ingredients

October 7, 2025 •

3 min read

Between 6 and 12 million head lice infestations occur each year in the United States among children 3 to 11 years of age. A common question is, does Rid have ivermectin? The answer is complex, as the Rid brand now includes different product lines with different active ingredients.

Quick Summary

The traditional Rid Lice Killing Shampoo does not contain ivermectin; its active ingredients are pyrethrum extract and piperonyl butoxide. However, the brand has introduced a newer product, Rid One & Done, which does use 0.5% ivermectin.

Key Points

Two Formulations: The Rid brand offers two different lice treatments: traditional shampoo with pyrethrins and piperonyl butoxide, and Rid One & Done with ivermectin [1.2.1, 1.3.1].
Traditional Rid: The classic Rid Lice Killing Shampoo does not contain ivermectin; it uses pyrethrum extract and piperonyl butoxide to kill lice [1.2.1].
Ivermectin Version: The newer product, Rid One & Done, contains 0.5% ivermectin lotion as its active ingredient [1.3.4].
Mechanism Difference: Pyrethrins act as a neurotoxin to paralyze lice, while ivermectin paralyzes lice by disrupting their nerve and muscle cells, and also prevents newly hatched lice from feeding [1.8.2, 1.9.1].
Super Lice: Ivermectin-based treatments like Rid One & Done are effective against "super lice" that have developed resistance to traditional pyrethrin-based products [1.3.1].
Application: Traditional Rid requires a second application after 7-10 days, whereas ivermectin lotion is designed for a single application [1.2.3, 1.3.1].
Check the Label: It is crucial to read the product's active ingredients list to know whether you are purchasing the pyrethrin or the ivermectin version of Rid.

Understanding Rid's Formulations: A Tale of Two Treatments

When treating a head lice infestation, understanding the active ingredients in your chosen product is crucial for effective results. The question of whether the popular over-the-counter (OTC) brand Rid contains ivermectin has become more common, and the answer depends entirely on which Rid product you are looking at.

Traditional Rid: Pyrethrins and Piperonyl Butoxide

For many years, the go-to product, Rid® Lice Killing Shampoo, has relied on two main active ingredients: pyrethrum extract and piperonyl butoxide [1.2.1, 1.6.2].

Pyrethrum Extract (Pyrethrins): Derived from chrysanthemum flowers, pyrethrins are a type of insecticide known as a pediculicide [1.6.1, 1.8.2]. They work by attacking the nervous systems of lice, leading to paralysis and death [1.8.2, 1.8.3].
Piperonyl Butoxide: This ingredient is a synergist. It doesn't kill lice on its own but enhances the effectiveness of pyrethrins by preventing the lice from breaking down the insecticide, thus making the treatment more potent [1.2.5, 1.6.1].

This traditional formula typically requires a second application 7 to 10 days after the first treatment to kill any lice that have hatched from eggs (nits) that survived the initial application [1.2.3, 1.6.2].

The Newcomer: Rid One & Done with Ivermectin

More recently, the Rid brand launched a new product called Rid One & Done™, which is formulated with ivermectin as its active ingredient [1.3.1, 1.3.2]. This product contains 0.5% ivermectin lotion and represents a significant shift in the brand's approach to lice treatment [1.3.3]. It is marketed as a single-application treatment that kills lice, including the pesticide-resistant variety known as "super lice," and also renders their eggs non-viable [1.3.1]. This product was made available over-the-counter following FDA approval for ivermectin lotion (previously prescription-only under brand names like Sklice) [1.5.4, 1.7.1].

Ivermectin Explained: Mechanism and Use

Ivermectin is an antiparasitic drug that works differently from pyrethrins. It binds to glutamate-gated chloride channels in the nerve and muscle cells of invertebrates like lice [1.9.1, 1.9.2]. This action increases chloride ion flow, causing hyperpolarization which leads to paralysis and death of the parasites [1.9.2].

A key advantage of topical ivermectin 0.5% lotion is its effect on newly hatched lice. While not directly ovicidal (egg-killing), it prevents newly hatched nymphs from feeding by paralyzing their pharyngeal pump, which leads to their death [1.9.1, 1.9.3]. This is why a single application is often sufficient, eliminating the need for extensive combing and a second treatment [1.3.1, 1.7.2].

Comparison of Lice Treatments

To clarify the differences, here is a comparison of traditional Rid, Rid One & Done (Ivermectin), and another popular OTC treatment, Nix.


Feature	Traditional Rid Shampoo	Rid One & Done (Ivermectin)	Nix Crème Rinse
Active Ingredient(s)	Pyrethrum Extract (0.33%), Piperonyl Butoxide (4%) [1.2.1]	Ivermectin (0.5%) [1.3.4]	Permethrin (1%) [1.2.5]
Mechanism of Action	Neurotoxin, paralyzes lice [1.8.2]	Paralyzes lice and prevents hatched lice from feeding [1.9.1, 1.9.2]	Neurotoxin, paralyzes lice [1.6.5]
Availability	Over-the-counter (OTC) [1.2.5]	Over-the-counter (OTC) [1.3.1]	Over-the-counter (OTC) [1.2.5]
Second Application	Required in 7-10 days [1.2.3]	Not required [1.3.1]	Often recommended [1.5.3]
Effect on Super Lice	May be less effective due to resistance	Clinically proven to kill super lice [1.3.1]	May be less effective due to resistance [1.4.2]
Age for Use	2 years and older [1.2.3]	6 months and older [1.3.3]	2 months and older [1.2.5]

Conclusion: Choosing the Right Treatment

So, does Rid have ivermectin? Yes and no. The classic Rid shampoo uses pyrethrins, while the newer Rid One & Done uses ivermectin to combat lice, including resistant super lice. This distinction is vital for consumers. The rise of super lice, which have developed genetic resistance to traditional pyrethrin and permethrin treatments, has led to the increased popularity and availability of alternative active ingredients like ivermectin and spinosad [1.5.2, 1.4.2]. When selecting a lice treatment, it is essential to read the label to identify the active ingredient and ensure you are choosing the most effective option for your situation, especially if you suspect a resistant strain of lice. Always follow package directions carefully for safe and effective use.

For more information on head lice treatment, you can visit the CDC's official page: https://www.cdc.gov/parasites/lice/head/treatment.html

Frequently Asked Questions

The active ingredients in original Rid Lice Killing Shampoo are Pyrethrum extract (equivalent to 0.33% pyrethrins) and Piperonyl butoxide (4%) [1.2.1].

Rid One & Done and Sklice both use 0.5% ivermectin lotion as their active ingredient for treating head lice [1.3.4, 1.7.1]. Sklice was originally a prescription-only brand that is now available over-the-counter [1.5.4].

Traditional pyrethrin-based treatments kill live lice but may not kill all their eggs (nits) [1.5.4]. A second treatment 7-10 days later is necessary to kill any lice that have hatched since the first treatment [1.2.3].

Rid One & Done, which contains ivermectin, is approved for use on children 6 months of age and older [1.3.3]. In contrast, traditional Rid shampoo is for children 2 years and older [1.2.3].

No, nit combing is not required for the ivermectin-based Rid One & Done to be effective, as it kills lice and makes the eggs they lay non-viable [1.3.1, 1.7.2]. Combing can be done for cosmetic reasons to remove dead nits and lice [1.7.2].

Ivermectin has a different mechanism of action than traditional pesticides like pyrethrins. It targets the nerve and muscle cells of lice in a way they have not developed resistance to, causing paralysis and death [1.3.1, 1.9.1]. This makes it effective against pesticide-resistant super lice.

Common side effects of topical ivermectin lotion are rare but can include eye irritation or redness, dandruff, dry skin, and a burning sensation on the skin [1.7.2, 1.11.3].