Nail biting (onychophagia) is a compulsive behavior involving biting one's nails or frequently putting them in the mouth. Widespread among adults, children, and adolescents, this habit is generally linked to stress or anxiety and can have consequences for the health of the nails, skin, and teeth.
Why do we bite our nails?
Nail biting most often occurs in situations of stress, intense concentration (at work, at school), or during smoking cessation. Boredom, hunger, or a feeling of discomfort can also trigger this behavior. Those affected often have an anxious personality, and are sometimes shy, introverted, or perfectionistic; the act serves as an unconscious way to manage emotional tension.
What are the consequences of onychophagia?
Nail biting can cause small skin lesions around the fingers, which can develop into infections, especially when the nail is bitten down to the surrounding skin. The underside of the nail naturally harbors germs and bacteria, which can then be ingested, increasing the risk of infection.
This behavior can also permanently deform the nails. The nail matrix, the tissue located under and around the nail that is responsible for its growth, can be damaged in a way that is difficult to reverse, giving the nails an irregular appearance in the long term.
Nail biting can also have repercussions on the teeth: repeated mini-traumas can scratch the tooth enamel, and in the long term, disrupt the occlusion (the way the teeth fit together), potentially leading to weakened, cracked or misaligned teeth.
Finally, some people develop social embarrassment related to the appearance of their hands, which may lead them to hide them or avoid certain situations.
How to stop biting your nails?
Several simple approaches can help to limit or gradually stop this behavior, especially when combined.
Regularly trimming and keeping nails short mechanically reduces the surface area available for biting, which can help decrease the frequency of the habit. Keeping your mouth occupied, for example by chewing gum, can also help discourage the habit.
Replacing the gesture with another gesture, such as manipulating a stress-relieving object, a pen, or playing with a lock of hair, allows you to channel the need to move your hands without using your nails. Taking care of your nails with regular manicures, polish, or even artificial nails can also be a psychological barrier: there are even nail polishes with a bitter taste specifically designed to discourage this behavior.
Regularly moisturizing your hands with a rich, nourishing cream makes your fingers less likely to be put in your mouth, while also repairing minor skin damage caused by nail biting. Wearing gloves or bandages over severely bitten nails can also provide an effective temporary physical barrier.
Finally, since stress and anxiety are often at the root of this behavior, practicing regular physical activity or relaxation techniques such asmeditation or yoga can help to channel tensions at their source, rather than simply treating the visible symptom.
How to treat bitten nails?
To help regrow and repair nails damaged by nail biting, plant-based oils like castor oil or olive oil are traditionally used to nourish, hydrate, and strengthen keratin. A weekly oil soak, leaving the nails in the oil for at least five minutes, can promote healthier regrowth. Our article on how to treat damaged nails details other complementary treatments, and our article on how to grow nails faster provides additional tips to support regrowth.
When should you consult a professional?
If onychophagia persists despite these approaches, or if it is accompanied by skin lesions that do not heal, a consultation with a general practitioner or dermatologist may be useful to assess the condition of the nails and surrounding skin.
When this behavior is clearly linked to significant stress or anxiety that is difficult to manage alone, support from a psychologist or psychiatrist can help to understand its origins and develop more appropriate coping strategies. There is nothing abnormal about seeking this type of help: nail-biting is a very common behavior and well-known to healthcare professionals.
Frequently asked questions about onychophagia
Is onychophagia considered a psychiatric disorder?
In most cases, nail-biting is a common stress-related habit, without any particular cause for concern. It is only in rarer cases, when the behavior is very intense and uncontrollable, that it may be linked to more specific disorders requiring professional help.
Does bitter nail polish really work?
Bitter-tasting nail polish can be effective for some people by creating an unpleasant association with the habit, but its effectiveness varies depending on the individual and their motivation to quit. It is often more effective when combined with other strategies.
How long does it take for nails to return to a normal appearance?
It depends on the extent of the damage to the nail matrix. For nails that are simply short but without deep damage, a few weeks to a few months of regular care is usually sufficient. In cases of more significant damage to the matrix, complete regrowth may take longer.