Baby Hairs: What Are They & Why Won’t They Grow

  • Medically reviewed by: Debra Rose Wilson, PhD MSN RN IBCLC AHN-BC CHT
  • Written by: William Slator
  • Last updated: 26/02/2024

When it comes to hair styling, baby hairs typically fall into two categories: the bane of an individual’s existence, or the chance for further stylistic creativity.

This article will discuss baby hairs. This will include a look at the two types of hair found on the body – vellus and terminal – so you can better understand where baby hairs fit in.

This article will also discuss the potential ways for you to grow your baby hairs longer than their current length. So let’s jump right in!

What are Baby Hairs?

Baby hairs are the short hairs that outline the hairline. They are often the same color as your typical scalp hairs, but shorter, thinner, and more tapered in appearance.

The amount of baby hairs you have, as well as their placement, is largely determined by genetics.

Vellus Hair vs. Terminal Hair

To understand baby hairs, you first need to understand what they aren’t. Baby hairs are often mistakenly lumped together with vellus hairs, though that’s not the case. To understand why that’s not the case, let’s dive deeper into the two different types of hairs: vellus and terminal.

Vellus Hairs

Vellus hairs are the short, translucent hairs found all over the body. The main function of vellus hairs is to regulate body temperature, both by insulating the body to protect against the cold and wicking away sweat to cool the body down.

Vellus hairs can become terminal, especially during stages of increased hormone activity, such as puberty and pregnancy. The most common places for vellus hairs to become terminal as you age include:

  • Chest
  • Abdomen
  • Legs
  • Arms
  • Pubic region
  • Feet
  • Face (in men)

It is possible, though less likely, for vellus hairs on the hairline to become terminal.

Terminal Hairs

When you think of hair, especially hair on the scalp, terminal hairs is likely what you’re thinking of. These are the long, dark strands that grow on the scalp and make up the bulk of your hair.

As the name suggests, terminal hairs are part of the longer-term hair growth process.

The growth of terminal hairs – including where, how long, how thick, etc. – is determined by hormones. Various things can interrupt hair growth, such as genetic predisposition to hormone sensitivity, certain medical conditions, stress, etc.

What Causes Baby Hairs to Stop Growing?

You may be wondering why baby hairs are so much shorter than their longer counterparts. Let’s take a look at the most common reasons for this.


The length of your hair growth cycles, as well as the pattern of your hairline, are determined largely by genetics.

Hair, both vellus and terminal, go through three stages of growth: anagen, catagen, and telogen. The difference between vellus and terminal, though, is the length of time that each phase takes.

In terminal hairs, the typical length of time for each cycle is as follows:

  • Anagen: Two to six years
  • Catagen: Up to a few weeks
  • Telogen: Up to a few months

There’s quite a range (especially with anagen) as the time will vary from person to person.

But what about vellus hairs? As these hairs are thinner and lighter colored, their anagen phase is significantly shorter. How much shorter? There’s not an exact ratio of terminal hair anagen phase to vellus hair anagen phase, but it can be less than a year and even just a few months.

If you want to increase the length of your baby hairs and even darken them, then the goal would be to lengthen anagen phase. I’ll discuss that more below.

Hair Damage and Breakage

Another reason for the presence of baby hairs, and likely the most common? Hair damage.

Hair damage at the hairline can be caused by many things, though harsh styling techniques and tight hairstyles are the most likely culprits. These are often performed over a long period of time – months to years – before the damage is noticed.

There are two types of damage most likely to cause hair breakage: physical strain, and chemical trauma.

Physical strain will occur as the result of poor brushing techniques, tight hairstyles, and improperly placed wigs and extensions. Chemical trauma can happen when the hair is exposed too often to harsh chemicals like bleach, hair dye, and perm.

Hair Loss Conditions

The most common conditions to target baby hairs are pattern hair loss and tension alopecia.

Pattern hair loss occurs largely in men, though it can affect women, too. In men, the telltale sign is an M-shaped hairline pattern that continues to deepen as the hair loss worsens. As it occurs at the hairline, baby hairs are some of the first that are impacted.

In this case, the hairs at the temples will experience shorter and shorter hair growth cycles. The hairs will become shorter and thinner until, eventually, they no longer grow. If left untreated, the pattern will worsen and eventually extend to the crown.

Next up is tension alopecia.

In discussing hair damage, we briefly touched on tension and how that can impact hair growth. Tension alopecia is the end result of continued tension on the hair.

Tension alopecia occurs when hair, typically those at the hairline, are pulled tightly on a regular basis. This may be from tight hairstyles (like braids and cornrows), too-tight headbands, or just poor hair brushing and styling techniques.

As the hair strands are constantly under stress, they begin to weaken and thin. This can eventually damage the hair follicle causing hair loss.

There are other hair loss conditions, such as alopecia areata, that are less likely to turn your terminal hairs into baby hairs. This includes alopecia areata which is characterized by patches of complete baldness throughout the scalp. As the condition contributes to total hair loss in the affected area, it will target all terminal hairs the same.

How to Promote Hair Growth

If you want to promote healthy growth of your baby hairs, then take a look at the tips below.

Remember that most baby hairs are just that, baby hairs. They may not be able to grow any more than their current length due to genetics and other factors. But if your baby hairs are really just due to hair damage or hair loss conditions, then these tips may help.

Stimulate Blood Flow

If you want strong, healthy hair then you’ll need a steady flow of blood to the scalp. Why? Because blood delivers oxygen and nutrients to the follicles just like it does to every other organ in the body.


If you want to take the medical route, then minoxidil is your best bet.

Minoxidil is a topical hair loss treatment approved by the Federal Drug Administration (FDA). It works by promoting cutaneous blood flow among other mechanisms (1).

The increase in blood flow will help to support the hair follicles in the area, both by delivering oxygen and nutrients and flushing out any waste or buildup. This is beneficial to vellus and terminal hairs, as both types require blood flow to complete the hair growth process.

Scalp Massage

Whether in addition to or instead of minoxidil, scalp massage can be a great addition to your hair care routine.

This technique will not only reduce scalp tension (especially great for those with pattern baldness), but it will also stimulate blood flow to the immediate area.

Lengthen Anagen Phase

If the end goal is to turn your baby hairs from vellus to terminal, or at least lengthen them in vellus stage, then lengthening anagen phase is crucial.


I mentioned the use of minoxidil above when discussing blood flow, but minoxidil actually has quite a few mechanisms for promoting hair growth. Among them is the ability to lengthen anagen phase (2).

How it works is minoxidil will prematurely end telogen phase, which reduces telogen phase shedding. This then triggers an early anagen phase.

While a few additional months may not seem significant, the combination of less shedding and increased hair follicle stimulation can be enough to trigger vellus-to-terminal hair growth.


Aside from minoxidil, there is one other FDA-approved hair loss drug on the market: finasteride.

Finasteride is largely prescribed to men with male-pattern baldness. It restores the hairline by targeting 5-alpha-reductase, the enzyme responsible for the levels of the androgen hormone DHT at the scalp.

In men with pattern baldness, less DHT means less inflammation. This means the hair growth cycle can resume its normal pattern without interruption.

What does this mean for those who don’t suffer from pattern hair loss?

Just like minoxidil, finasteride doesn’t have just one mechanism. Aside from its target of 5-alpha-reductase, it has also been shown to have a positive impact on anagen phase hair growth.

Studies have shown that finasteride not only increases the number of hair follicles in anagen phase at any given time, but it also improves the anagen to telogen ratio (3).

What does this mean?

At any given time, the hair follicles on your scalp are in various stages of the hair growth cycle. The ratios aren’t exact, but a common breakdown is 90 percent in anagen, less than 1 percent in catagen, and about 10 percent in telogen.

According to the study referenced above, those who used finasteride saw a “net improvement in the anagen to telogen ratio of 47%.”

That improvement is quite significant, especially if you suffer from pattern baldness. If your hair is otherwise healthy, though, then the improvement isn’t likely to be so significant but the benefit can still be seen.


Baby hairs are a common phenomenon, and almost everyone has them. For some, they can be easily ignored while for others they can be a nuisance.

If you want to grow your baby hairs, there are potential ways for doing so. Just keep in mind that genetics does play a large part in their placement and length and, as such, you can only do so much to contribute to their growth.

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