Onyx Stop the Bite Nail Polish Review

Onyx Stop the Bite Nail Polish Review

Price: $8

Sanitary & Health
Ease of Use
User Rating

Effective when used in conjunction with another stopping product, low cost.

Does not work when sleeping, bad bitter taste becomes acquired in about a day, must reapply every day.

Our Full Review

Onyx Stop the Bite is a treatment for the finger nails that is meant to ween the habit of nail biting by application of a very bitter tasting formula. Onyx also claims to discourage thumb sucking, although evidence suggests otherwise.  The product claims to be for kids age four and up. For serious thumb suckers, you need something that will physically prevent the thumb from being sucked on.

Anti-Nail Biting Polish DOES NOT WORK for thumb suckers. It is designed for daytime nail biters – and only offers a little reminder. Obviously 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 taste buds to dislike it yet. Nail polish was developed for nails, not thumbs.

Nonetheless, Onyx has been a top seller for many years. It is inexpensive and is easy to try, and if it does not work then the lost money is not very much. There are several good reasons to quit nail biting, including:

  • Spreading of germs and bacteria
  • TMJ problems
  • Chipping teeth
  • Nail infections
  • Lack of self-confidence and embarrassment

bitten nail fingers

Onyx works as either a base coat or top coat, and dries clear but a little shiny, which is non-ideal for men. It is simply brushed on and dries quickly.

Amazon shows over two thousand reviews and an average product review user rating of four stars – not bad for a habit-breaking solution that is heavily dependent upon the user. Note, that 10% of the reviews are a 1-star, meaning that for about 10% of the people it does not work at all.

Biggest Complaints

  • Peels off too easily, leaving small pieces left behind that get swallowed
  • Frequent application needed
  • The terrible taste gets transferred to anything else touched, like food when eating
  • (Kids) get used to the taste quickly, or it does not bother them – does not work while sleeping

Biggest PROS

  • Tastes horrible
  • (mostly adult) Works quickly, results immediately

Do you need a reminder throughout the day to stop putting your fingers in your mouth? Then Onyx may be a good solution for you. Other brands of anti-nail biting polishes may deliver similar results for.

Although Onyx Stop the Bite can work on its own to quit finger sucking, it is most successful when used along with a physical device – one that obstructs the thumb from the mouth. We recommend using the nail biting treatment with another product that physically obstructs the thumb from entering the oral cavity.

Small children often develop a tolerance for the bitter taste in minutes or hours, and their willpower to continue the habit overpowers their dislike for the taste. Your child will definitely find the bitter taste disgusting at first, but a stubborn child will quickly get past it. Think of Onyx like the first black coffee you tasted, it was gross at first but then you learned to like the bitter stuff.

For the night-time thumbsucker no anti-nail biting treatment will work. Often, kids will go to bed without the thumb in the mouth but while asleep the digit makes its way into the mouth (this is perfectly natural until the habit is stopped). Unfortunately, their taste buds are essentially turned off while asleep so their brain does not get the “gross” signal, and when they awake they’ve sucked off all those bitter chemicals. It is involuntarily and not their fault.

What are Onyx Stop the Bite ingredients?

The Onyx nail treatment primary ingredients include Butyl Acetate, Ethyl Acetate, Isopropyl Alcohol, Acrylates Copolymer, Cellulose Acetate Butyrate, Denatonium Benzoate, Dipropylene Glycol Dibenzoate. You are concerned for the safety of your children, and want to know what it is made of, how processed and “chemical” it is, and what are the side-effects of Onyx. Unfortunately we don’t really know its safety because the FDA has not reviewed it. However, its competitor, Mavala Stop claims that its polish is harmless, and many of the ingredients are similar.  However, we aren’t so convinced!  Lots of reviews, especially from concerned parents about their kids, say that their child developed a stomach ache and sometimes kids will throw it up.

Physical retailers sell Onyx too, but the best price will be a little online. You can probably find Onyx Stop the Bite at Walgreen, CVS, or Walmart.


  • Onyx nail deterrent is most effective for adults, or for thumb sucking when used with another device that physically obstructs thumb sucking. Designed for daytime nail-biters who are already motivated to stop, it is a good deterrent.
  • Invisible and non-obtrusive.
  • Does not work for stubborn thumb suckers, or at night, and must be reapplied frequently.

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  1. I found this website while looking for something better than the anti-nail biting polish I bought for my 8 year old. I bought Mavala Stop, and just like you said, it did not work. My little boy sucks his thumb at night, and once he goes to sleep his taste buds seem to turn off, so this does not work for him.

  2. horrible thumb sucking thing it just doesn’t work. It tastes bad but not bsd enough. And if you spill it it can ruin your clothes.

  3. It took Saedie (age 5) four days to stop. There were no tears. There were many curled-up and grimacing faces as Sadie unconsciously popped that thumb in from time to time and got a taste of the nasty stuff. It is nasty I tried it. Bitter and lingering. Sadie now likes painting her fingernails pink.

  4. Great comments. You are correct. Anti-nail biting polish does not work at night, when most thumb sucking happens. Other products are much more effective.

  5. Cheap enough to try. but the taste gets onto other things and it is true this definitely doesn’t work at night. I’ve got two kids, three and nine. Works for the nine year old who is always sucking his index finger. The little one who no longer get the pacifier sucks rigth through it though. It might work for you.

  6. anti nail biting polish works good for nail biting but not thumbsucking. Thumbsucking happens mostly at night, and bad taste doesn’t matter when sleeping. 5 stars for product overall, but 2 stars when related to stopping thumb sucking

  7. Taste transferred to vegetables I sliced for soup. End result was the soup ended up tasting bitter. Three days later and the taste is still in my mouth. Help!!!!

    1. The bitter taste will eventually fade. For a short while you’ll notice the bitterness spreading, until the habit is broken and you no longer need the bitter polish. No Pain No Gain! Hang in there.