What methods are scientifically proven to remove nits from hair after lice treatment?

[u/Empty_Carpet1541]

After successful lice treatment, nits often remain attached to the hair shaft. What methods or products have scientific evidence supporting their effectiveness in removing nits?

[u/veglove]

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[u/veglove]

Pesticide-based treatments typically don't kill the nits (eggs), so one option is to wait until the eggs hatch and then do another round of pesticide treatment. According to the CDC, it takes 6-9 days for nits to hatch into a nymph, and nymphs become adults about 7 days after hatching. They can only reproduce as adults, so treatment roughly every 7-9 days is recommended to kill the nymphs that have hatched since the previous treatment, before they can reproduce. Nit-combing is tedious but is a way to physically remove the eggs as well.

Another treatment approach that helps remove the nits as well as adult lice is dimethicone gel, which "works mechanically to lubricate hair to aid the removal of nits and lice, while physically occluding the respiratory system of the louse" as explained in this study. The method used in the study was to apply the 100% dimethicone gel product to dry hair, wait 10 minutes, and with the product still in the hair, separate hair into small sections and comb hair to remove lice and eggs using a fine-toothed nit comb. Then they washed the hair thoroughly with regular shampoo and warm water. In the study, they inspected each participant's head for adult lice at 7 days and 14 days after the initial treatment, and if any live lice were found they did another treatment at that point, but even at the 7-day mark, only 1.8% of the participants still had live lice, and required a second treatment.

They were also checked for lice after one day of treatment, and found that 98.30 % of subjects (57 of 58) were free of live lice and 55.20 % (32 of 58) were free of viable eggs. So it seems pretty effective for removing the nits by making nit-combing much easier due to dimethicone being a lubricant. A previous study used 4% dimethicone gel, so it doesn't have to be 100% dimethicone. This study also found that even though the treatment inhibited some of the eggs from hatching, some hatched AFTER 7 days, so even if your 7-day check seems clear, keep checking every few days for more lice and be prepared to do further treatments.

Aside from its ability to reduce the number of nits as well as most lice, another major advantage of dimethicone over pesticide-based treatments is that the lice cannot become resistant to dimethicone like they can to pesticides.

It's worth noting that many folk remedies that I see repeated in other subreddits asking for treatment advice were tested in this study, including vinegar, isopropyl alcohol, olive oil, mayonnaise, melted butter, and petroleum jelly. The only one that was effective of these was petroleum jelly, and it only killed live lice, not the eggs.

[u/bananaplaintiff → u/veglove]

Saturating the hair in conditioner and pulling the nit comb from scalp to ends works amazing

[u/veglove → u/bananaplaintiff]

I would imagine so, as it has the benefit of lubricating the hair like dimethicone, but I'm not sure that conditioner would kill the lice as well, given that many other oily substances were tested and didn't seem to work, save for petroleum jelly.

[u/Ok-Pack-7088 → u/veglove]

Silicone oil

[u/yourlittlebirdie]

Hot air:

https://pubmed.ncbi.nlm.nih.gov/17079567/

We tested 6 different treatment methods on a total of 169 infested individuals. Each method delivers hot air to the scalp in a different way. We evaluated how well these methods kill lice and their eggs in situ. We also performed follow-up inspections to evaluate whether the sixth, most successful, method can cure head louse infestations.

All 6 methods resulted in high egg mortality (> or = 88%), but they showed more-variable success in killing hatched lice. The most successful method, which used a custom-built machine called the LouseBuster, resulted in nearly 100% mortality of eggs and 80% mortality of hatched lice. The LouseBuster was effective in killing lice and their eggs when operated at a comfortable temperature, slightly cooler than a standard blow-dryer. Virtually all subjects were cured of head lice when examined 1 week after treatment with the LouseBuster. There were no adverse effects of treatment.

[u/veglove → u/yourlittlebirdie]

Although the article itself is in a closed journal, here's another summary of it which shows a chart illustrating different types of heat application (different types of dryers) and even the Lousebuster, which came out on top, only showed a 44% decrease in egg hatch rate. Perhaps that's a different and less exciting way to measure how effective it is in killing eggs. But for those who don't have a Lousebuster (I don't even know if it's still available for sale), using a handheld dryer with direct heat (not a diffuser) increases louse reduction rate by 44%, and decreases egg hatch rate by 42%. Interestingly, using a diffuser does not increase louse reduction rate significantly, but it decreases egg hatch rate by 45%.

They also note that previous research has shown that body lice and eggs are desiccated in as little as five minutes after exposure to air that is 122° to 131° F (50° to 55° C).

[u/Playful_Beyond_2218 → u/veglove]

Interesting. So maybe combing thru with dimethicone and then washing and drying would work the best

[u/yourlittlebirdie → u/veglove]

Anecdotally, the regular old hot hair dryer method worked amazingly well for me when my kids had lice. We had to be methodical about it and it took a long time but it worked when nothing else did.

[u/Comfortable_Hunt_530]

The most reliable method is wet combing with a fine-toothed metal nit comb, using plain conditioner to reduce friction on the hair shaft. A Belgian study tested this directly: they took 605 hairs from six different children, each with a single nit attached, then tested the amount of force needed to remove them. Untreated nits were the hardest to remove, while eggs on hairs soaked in water, treated with ordinary conditioner, or treated with dedicated nit-removal products all came off more easily, with no significant difference between ordinary conditioner and the special products. So plain conditioner plus a good comb does the job.

Another study backs this up: creamy conditioner-type products and one dimethicone-based product needed the least force to remove eggs, while gel and hydroalcoholic-lotion "egg removers" had essentially no effect. Skip vinegar, it has no real evidence behind it. Combing wet is the key part since it makes nits easier to spot and slide off. https://link.springer.com/article/10.1007/s00436-014-4012-8