Thum Thumb Sucking Nail Biting Treatment Review

Thum Thumb Sucking Nail Biting Treatment Review

Price: $18

Sanitary & Health
Ease of Use
User Rating

The bitter agent, cayenne pepper extract, is natural.

There is no evidence that Thum has been tested for safety.

Our Full Review

Thumb sucking and nail biting is a common behavior in young ones but left unchecked, these may grow into bad habits.  Do you feel your child should have outgrown thumb sucking by now? Perhaps you or your child is trying to break the nail biting habit, and looking for solutions. Whichever the case, there are products on the market that can help crush these harmful habits for good. One such product is the Thum thumb sucking nail biting treatment. In our review, we dive into what this anti-nail biting and thumb sucking preventive product is, and how it may help you or your kids break these unwanted behaviors.

What Is the Thum Thumb Sucking Nail Biting Treatment?

The Thum Thumb Sucking and Nail Biting treatment is a liquid product that is applied like nail polish. It serves as a preventative method for nail biting because it contains strong, distasteful ingredients. When treated fingers, nails, or thumbs are put in the mouth, Thum leaves behind a bitter, spicy taste.  The idea behind its effectiveness is that a nail biter or thumb sucker will eventually associate the unsavory taste with putting fingers or thumb in the mouth. This product can be purchased online at Amazon where it currently sells for $6.99, or it can also be purchased at Wal-Mart for $7.37.

Anti-Nail Biting Polish DOES NOT WORK for thumb suckers at night. It is designed for daytime nail biters – obviously it won’t work while your child is sleeping and their taste buds are turned off. Children under four years old don’t dislike the taste because they haven’t yet developed a bad taste for it yet. Some kids get used to the bitter flavor unless it is very, very strong. Nail polish was developed for nails, not thumbs.

How Does the Thum Thumb Sucking Nail Biting Treatment Work?

According to the manufacturer packaging, use Thum by brushing the solution onto clean, dry fingernails or thumbs. Allow the product to fully dry. Apply the product twice a day, or reapply if it wears off. If you need to remove it, this can be done by using standard fingernail polish remover.  

Thum claims to be effective for adults, teens, and children in breaking the habit of nail biting or thumb sucking. The foul-tasting agents in the product are meant to dissuade nail biters and thumb suckers from putting fingers or thumbs in the mouth.  

Thum Thumb Sucking Nail Biting Treatment Ingredients

The Thum Thumb and Nail Biting treatment contains cayenne pepper extract, citric acid, isopropyl alcohol, acetone, and lacquer.  The cayenne pepper extract (capsicum annuum) is the bitter, spicy agent that is purported to break the nail biting or thumb sucking habit.

Pros for This Nail Biting Treatment

  • Thum is competitively priced for what it is, and relatively cheaper than similar products on the market.
  • It leaves an offensive taste and sensation in the mouth which may be effective in breaking nail biting or thumb sucking habits.
  • The bitter agent, cayenne pepper extract, is natural, whereas some other products use synthetics as their main deterring ingredient.
  • Thum claims their product does not cause nausea or stomach upset.
  • It is made in the USA

Cons for This Nail Biting Treatment

  • This is not the strongest bitter agent on the market. 
  • Some users report that the Thum thumb sucking and nail biting treatment was not effective because the taste was not powerful enough to break the habit. Other users claim they either didn’t experience the bitterness at all, or they quickly became so accustomed to it that the treatment was rendered useless.
  • Thum does not contain any soothing agents such as vitamin E which work to heal sores from sucking or fingernail biting.
  • You may need to reapply many times, as the solution does not always stay on long-term.
  • There is no evidence that Thum has been tested for safety. This is unsettling, especially if used on children. 
  • While other remedies on the market offer additional support aids, Thum does not. It is a stand-alone product.

Thum Thumb Sucking Nail Biting Treatment for Thumb Sucking

As mentioned, Thum is marketed as a multi-purpose product in that it may help break nail biting as well as thumb sucking habits. The  Thum Thumb Sucking treatment as a stand-alone product may not be the best solution. Namely, because the formula might not be powerful enough to deter stubborn thumb suckers. Furthermore, crushing the thumb sucking habit is best done with a mix of resources such as incorporating thumb guards, behavioral modification, and positive reinforcement.


After a thorough review of the Thum Thumb and Anti-Nail Biting treatment, it seems clear that this product has both advantages and disadvantages. Its effectiveness is likely dependent upon how severe your or your child’s habit is, and other measures are taken to curb the urge to nibble nails or suck thumbs.  That said, there are alternative products on the market today that render better results.  The choice is yours. Simply know that other solutions are available that might yield higher success rates in breaking the nail biting or thumb sucking habit for good.  


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  1. My 4 year old keeps his hands in his nose and mouth. This doesn’t work, he likes it. He wants me to keep putting more on. I tried it and like someone else mentioned it’s a bit spicy, kind of yum. Not good for deterring nail biting or booger eating.

  2. My three year old’s nails were back in her mouth 5 minutes after application. I asked if they tasted bad, and she said they didn’t taste like anything. The ingredients are not anything I want her chewing and eating, that is for sure.