The Truth about Baby Sucking on Bottom Lip

What should you do when you see your baby sucking on bottom lip? Honestly, the best answer to this question is to get the camera because your baby’s facial expression during this activity is just priceless!

However, you’re still wondering why your baby is sucking in this manner. Also, you ponder on whether or not the sucking will lead to dental issues. Looking at some logical reasons for this habit can help you to remain assured that your baby will be ok and is simply going through another stage of development.

Because you need to consider the baby’s age as an important factor when this habit develops, there are a few possible reasons for this mannerism.

The Reason Depends on the Age

Why you see the baby sucking on bottom lip depends largely on age. Consider the following causes during various stages of development:

  • Initial sign of hunger before proceeding to gnaw on fists
  • Soothing one’s self instead of crying
  • Teething
  • Pressure or nervousness in older toddlers and children

Could Your Baby Be Ready for More Substantial Food?

Don’t be surprised if one evening, while enjoying dinner with the family, you get this feeling like someone is watching you. When you look over to find your baby sucking on bottom lip, you might notice a wistful expression in his or her eyes while looking right at you if not glancing over at your plate and smacking the lips periodically.

Yes, you guessed it! Your baby wants a taste of what you’re eating. This is only natural considering that the senses, especially smell and taste, play a major role in your baby’s development. Plus, this can be a sign that he or she wants something more solid than what formula or breast milk can provide.

Before you give in to that sad little expression, you will need to determine whether or not your baby should move on to solid food. Here are some general signs:

  • Has reached 4 months of age (this is just a very general estimate; some babies might need to wait a bit longer)
  • Has reached 13 pounds or more
  • Sits with less assistance and can hold head up
  • Frequently puts hands in his or her mouth
  • Is able to use non-verbal cues to express hunger or disdain in regard to food (lip-smacking, reaching for food, or turning head away to reject a spoon or bottle)
  • Opens mouth and keeps tongue inside when spoon fed
  • Sucks in the bottom lip

Some foods that are introduced at different ages include:

  • A single grain cereal, like rice cereal mixed with breast milk or formula for babies at about 3 to 4 months
  • Pureed foods like vegetables or fruits at 4 to 5 months one at a time a few days apart
  • Pureed or mashed up meats at 6 to 8 eight months one at a time also

For more information on introducing cereal and other foods, take a look at this video.

The Sucking Has a Soothing Effect

As your baby gets older, he or she gradually learns to comfort him or herself. More often, that coping mechanism takes the form of sucking either the hand, thumb, or lower lip. After reaching three months, this reflex reaction can be a sign of self-comforting, as opposed to hunger. So you would have to be careful to not mistake this sucking action as a sign of hunger in order to avoid Lactose Overload (source).

Basically, you would need to keep in mind that if your baby calms down after sucking the lower lip or hand, then food is not always required. If the sucking continues as fussiness increases, this could be a sign of hunger or even teething.

Moreover, if the baby continues to suck on the bottom lip with little or no reaction, this usually means that he or she simply discovered something new the bottom lip! Just like young infants become fascinated with their hands as a new toy, they also develop increased awareness of their lips and tongue.

First Signs of Teething

First Signs of Teething

Anymore, it’s not uncommon for babies to start teething as early as 3 months. However, the teeth won’t actually cut through the gums for about another month or two.

So one sign that the teething process is about to commence is the baby sucking on bottom lip along with increased drooling. Why does this happen? The bottom lip combined with the sucking action can soothe the sore bottom gums. The first two teeth to cut through are the two bottom front ones, so this action is your baby’s way of dealing with teething discomfort.

Has No Significance…until baby sucking on bottom lip continues into childhood

For the first year of life, a baby’s sucking reflex and sucking action are perfectly normal signals at various stages of development. A toddler, on the other hand, might continue this habit of sucking on the bottom lip as a sign of stress. This can be caused by a change in routine or environment.

While this behavior is temporary, more often than not, you might need to consult with your pediatrician or dentist if it continues and other symptoms or behaviors accompany this habit.


All in all, your baby will adopt new behaviors, like sucking on the bottom lip, as he or she grows older and reaches new stages of development or exposed to new stimuli. This action can also relate to two other milestones, like teething or learning to self-soothe.

Nonetheless, two things to remember are:

  • To keep from worrying when your baby starts sucking on the lower lip or fist
  • To keep from over-feeding each time this behavior occurs
  • To contact your pediatrician if any behavior is accompanied by extreme fussiness and/or fever, or seems out of the ordinary parameters of development

Remember that this phase is only temporary.

Other Related Articles:

  1. Have you ever wondered why baby sucks on fingers?
  2. Can you overfeed a breastfed baby?
  3. Baby “Teething Fever”: Look at the Facts behind It
  4. Fever in Babies: 7 Important Things You Might Not Know
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Sarah Palmer
Hi! I'm Sarah. My husband and I have a beautiful little girl; plus we’re anxiously awaiting the arrival of Baby #2, so this is a very exciting time for us. Throughout this amazing journey called Parenthood, I’ve learned so much and love sharing my experiences with other parents at I'd love to share my discoveries with you too!
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  1. Nice one for new parents

  2. […] months.On my end, the safest time to transfer your young ones to their new room is when they start "baby sucking." It is the first sign that they are going to start teething. It is also an indicator that your […]

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