Hair Density: What Is It, Types & How to Determine Yours

Hair density refers to how much hair you have—and it can play a role in how full your hair looks. Learn how to determine your hair density here.

By Jené Luciani Sena & Powered By L’Oreal Professional Products Division

Update Date: 01 Oct 2024

Hair density and hair thickness are often confused with one another. While both play an important role in determining how full a person’s mane appears, the two terms measure very different things. Thickness refers to the size (or diameter) of your individual strands of hair. Hair density, meanwhile, is a measure of how much hair you have.

As with most other things in haircare, how dense your hair is is largely influenced by your genetics, though age, environmental factors, and your lifestyle can play a role, too. Ahead, we’ll explain what you need to know about hair density, including what it is, why it matters, and how to care for high, medium, and low-density hair.

What Is Hair Density?

Hair density refers to the number of hair follicles you have on your scalp—in other words, how many hairs are on your head. According to the National Institutes of Health (NIH), most healthy adults have between 80,000 and 120,000 hairs on their scalp alone. A higher number is indicative of dense hair, while a lower number typically means you have low-density hair.

As a general rule, the denser your hair, the fuller it’ll appear—though other factors can affect how full your mane looks, too. The most notable is your hair thickness, or how wide (in diameter) your individual strands are. Like density, the diameter of human hair varies from person to person. Thin hair is the finest hair type, followed by medium, then coarse. You can have thick, low-density hair (thick strands, but fewer in number), fine, high-density hair (thin strands, but plentiful in number), or any other combination between the two—it mostly comes down to a matter of genetics, your age, and your lifestyle.

Types of Hair Density

There are three categories of hair density: low, medium, and high.

Low-density hair

Those with low-density hair (often referred to as “thin” hair) have fewer strands of hair than what is considered average. The hair may appear sparse or flat, and the scalp may be easily visible, especially when the hair is parted or pulled back. You can be born with low-density hair, but it’s often associated with aging. As you get older, your hair follicles may begin to shrink and eventually stop producing hair, which can make your hair appear thinner. Other factors, such as stress, certain medical conditions ( including pregnancy), and improper haircare practices can also make your hair sparser.

Medium-density hair

Medium-density hair is just what it sounds like—hair that’s neither dense nor sparse. Depending on the thickness of your individual strands, your scalp may be visible when parted or pulled back, or completely obscured by your mane. You can’t go from low to medium-density hair, but you can go from having dense hair to having medium-density hair. This loss of density can occur with age or as a result of stress, hormonal fluctuations, or certain lifestyle habits. If you find your hair begins to appear thinner than it once did, it may be worth checking in with your doctor to ensure there are no underlying issues at play.

High-density hair

Dense hair has more follicles per square centimeter than what is widely considered “average.” If you have dense hair, your hair likely appears full, regardless of how thick your individual strands are. While dense hair can, in many ways, be a blessing, it requires special care to look and feel its best, as it can be heavy and often requires more effort to style than low or medium-density hair.

How To Determine Your Hair Density

Determining your hair density involves assessing how much hair you have. Fortunately, you don’t have to get out the magnifying glass and count every strand on your head—there are a few simple tests you can do at home to figure out where your hair falls on the density spectrum.

• Visual inspection method: The simplest way to get an idea of your hair density is by looking at it (probably more closely than you normally do). Wash and dry your hair as usual, skipping any styling products you usually use, and stand in front of a mirror. Take stock of what you see—does your hair look thin and sparse, or full and voluminous? Can you see your scalp without moving your hair? Thin-looking hair with a visible scalp is typically indicative of low-density hair. If you see very little no to scalp and your mane appears full and voluminous, chances are good your hair is high-density. Those who see some scalp, but only on certain areas of the head, generally fall into the medium-density category.
• Ponytail circumference method: If the visual inspection method doesn’t give you a clear idea of how dense your hair is, try this test. Start by gathering your clean, dry hair into a ponytail at the back of your head. For the best results, you want to make sure the ponytail is secure, but not overly tight. Then, wrap a flexible measuring tape around the base of your pony to measure its circumference. The higher the number, typically, the more dense your hair. Of course, this method only works if your hair is long enough to pull into a ponytail (and doesn’t account for hair thickness, which can affect the circumference of your pony, too).
• Ask a pro: Consulting an expert hairstylist is far and away the best way to determine how dense your hair is. Professional hairstylists spend all day looking and caring for hair—they’ll be able to give you a clearer sense of how dense your strands are in comparison to the norm.

What Factors Can Affect Hair Density?

There are many factors that can affect your hair density. Here are a few, and how they play a role.

• Genetics: Your genetics play a major role in determining how dense your hair is. If your parents have low-density hair, there’s a good chance you will too, and vice versa. Your ethnicity also plays a role—one study published in 2022, for example, found that those of African and Asian descent typically have lower hair density than Caucasians. Amongst Caucasians, blondes had the highest hair density, followed by brunettes, then redheads.
• Age: As you age, the number of active hair follicles on your scalp can decrease. Some follicles may shrink and become less effective at producing hair, leading to reduced density. Individual strands may also become thinner, which results in less overall volume.
• Haircare practices: How you care for your hair can affect how dense your hair is. Frequently wearing your hair in tight hairstyles, heat styling, or regularly undergoing chemical treatments (such as bleaching, coloring, or perming your hair) can damage your strands and, in some cases, lead to hair thinning. When undergoing a major hair transformation, it’s best to visit a professional who can help you reach your goals with minimal risk of damage.
• Health factors: Hormonal fluctuations, chronic stress, and some medical conditions can contribute to hair thinning or loss. If you notice your hair thinning dramatically—or if the thinning is new or unexpected—consult with your doctor.

Tips for Managing Different Hair Densities

Taking your hair density into account when building a routine, styling your hair, and even getting your hair cut can all help ensure your mane looks and feels its best. Here are some tips to keep in mind next time you revamp your routine or hit the salon.

Tips for low-density hair

If your low-density hair looks flat or thin, consider asking your stylist for a cut that emphasizes texture, such as the shag. This highly-layered cut gives your hair body and movement and creates the illusion of more volume, even if your strands are on the sparser side.

To keep the volume going strong, consider swapping out your go-to shampoo and conditioner for a volumizing system. We love the Pureology Pure Volume Shampoo and Conditioner, which helps remove buildup and enhances volume without weighing down the hair. For extra lift, mist the Matrix Total Result High Amplify Wonder Boost onto your roots before styling your hair—the silicone-free styling aid provides body and movement with lightweight, flexible hold. And to preserve your hair, try to keep tight hairstyles—and heat styling—to a minimum.

Tips for medium-density hair

Caring for medium-density hair is typically pretty easy, as it’s neither noticeably thin nor overly voluminous. As a general rule, you’ll want to follow a gentle haircare routine that addresses your concerns (such as frizziness or dryness) without stripping your hair. Try the Biolage Professional Hydra Source collection. The hydrating lineup includes everything you need to care for your mane, including a shampoo, conditioner, deep conditioning mask, and styling treatments (five, to be exact). We’re especially fond of the line’s Blow Dry Shaping Lotion, which protects hair from temperatures up to 450 degrees Fahrenheit and reduces drying time—so you can perfect your at-home blowout without subjecting your strands to excessive damage. (Check out our review of the lineup for more details).

If your hair sometimes falls flat by midday or you want to pump up the volume for a special occasion, consider adding the Redken Full Volume Mousse to your styling routine. The conditioning formula moisturizes hair, protects against heat and humidity, and volumizes hair from root to tip for maximum body and lift.

Tips for high-density hair

Managing bulk and thickness is the primary challenge for those with high-density hair types. While your hair may seem like a dream to those with sparser strands, all that hair can take a bit of elbow grease to tame and maintain. To remove unnecessary weight—without affecting your length—consider asking your stylist for a layered chop with face-framing pieces or bangs (layers can also help keep your hair from looking poofy).

Another tip: Steer clear of volumizing haircare products—you don’t need them—and instead stick with smoothing formulas designed for thick, coarse hair. The Redken Frizz Dismiss Shampoo and Conditioner are great picks, as they help smooth the hair, fight frizz, and boost shine. Plus, the pair is suitable for all hair types and textures. If you’re looking for something designed specifically for curls, try the brand’s All Soft Mega Curls line, which includes a shampoo, conditioner, and a hydrating leave-in treatment.