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Flat Hair: 5 Potential Causes, Plus How to Revitalize It

BY Felicia Ler

Every time a hair care commercial comes on, the model’s soft, voluminous, billowing waves never fail to spark envy. And who could blame you? It’s not like you have a professional hairdresser primping every strand on your head for a picture-perfect mane. 

But there’s no reason you have to resign yourself to a lifetime of flat hair. It’s possible to transform your lanky locks into bouncy tresses full of vitality. It all starts with pinpointing the culprits of your flat hair and using the right tools (and products) to tackle them.

Flat Hair vs. Fine Hair: What You Need to Know

Flat hair often rears its head among fine-haired folks. Sebum, hair products, dirt, and other impurities tend to weigh down thin hair strands. The flatness is even more pronounced for those with fine, straight hair as these residues can travel effortlessly from the roots to the tips.

That said, you shouldn’t assume flat hair naturally means fine hair or thin hair. Other hair types, such as those with thick manes and corkscrew curls, are also susceptible to droopiness, particularly at the top of the head.

If you have curly hair coupled with an oily scalp, the excess oil may not necessarily reach the ends (due to the wavy trajectory of your hair fibers), but it will most likely concentrate around the roots. As such, your curls may seem dry from the mid-length area to the tips, then veer towards oiliness at the roots — hello, flat hair at the top!

The bottom line is that flat hair can happen to anyone, regardless of your hair type.

What Causes Flat Hair?

There are myriad reasons why your hair isn’t looking as perky as you’d like. To confound the matter further, there’s usually more than one factor behind the scenes. Here are a handful of common causes of flat hair. 

1. Overactive Sebaceous Glands

Did you know that besides your face, chest, and back, your scalp houses the largest concentration of sebaceous glands on your body? Scientific evidence indicates these sebum-producing glands typically peak during puberty. Sebum secretion activity typically plateaus in your 20s and 30s before declining with age (sebum production usually falls sharply after menopause). However, if you have overactive sebaceous glands, the excess oil can result in greasy hair that looks flat at the top. Research also suggests your bad hair days during “that time of the month” may be related to a buildup of sebum on your scalp.

Aside from these factors, a diet high in meats, dairy products, soft drinks, and alcohol can also kick the sebaceous glands into overdrive. If you’re physically active and sweat frequently, you’ll likely experience more sebum, too.

Those with fine hair are likely to experience oily hair from the roots to the ends. The geometry of fine hair strands allows natural oils to travel easily down the hair shaft unlike curly and coily hair types, which tend to loop and zig-zag, acting as roadblocks for said oils. This weighs your hair down from top to bottom, resulting in a rather flat appearance overall. Add in dead skin cells and product buildup (see next section), and you have a volume-killing situation.

2. Product Buildup

Product buildup is another common factor behind lifeless, flat hair — sticky hairspray, dried mousse, and dry shampoo are just a few potential culprits. Not only does product residue make your hair look (and feel) gunky, its actual weight can add up significantly. In fact, some polymers found in hair care products, like deep conditioners, resist water and weigh down hair even after shampooing. The result is less bounce and more blah.

3. Unsuitable Hair Care Products

Using the wrong hair care products can snuff out hair volume. For example, rich, moisturizing shampoos and conditioners may seem like a good idea in theory. But in practice, they may not be giving your hair the volumizing effect it needs (unless they are specifically labeled as such and contain ingredients that actually boost volume). 

As it turns out, ultra-hydrating ingredients may impact your scalp’s oil production without making a dent in the existing product buildup. 

4. Lack of Nutrients

You are what you eat, which is why your diet can affect how voluminous your hair appears. Overloading on processed carbs instead of healthy foods may be the reason why you’re battling not just flatness, but the whole works (translation: frizzy, damaged, and dry hair). Consider consuming more hair-healthy nutrients such as: 

  • Sweet almond oil: This oil from almond seeds is rich in vitamin E, oleic acid, and linoleic acid, which helps promote hair health and resilience to boost overall volume.
  • Quinoa: A potent source of 9 essential amino acids, quinoa can strengthen and nourish your hair and scalp for healthier, fuller-looking locks.
  • Rosemary leaf extract: This herb has been shown to stimulate scalp circulation and hair growth to optimize hair health and volume.

5. Improper Hair Styling

The wrong hairstyle can make your flat hair even more pronounced. Think back to the times when you’ve gone overboard with the flat iron to neutralize frizz (oops!). Or perhaps your hairstyle isn’t right for you — a lack of layers or hair that’s too long can make your mane look heavy and weighed down instead of breezy and full of life.

How to Revitalize Flat Hair: The Do’s and Don’ts

Learn how to revitalize flat hair

Thankfully, flat hair isn’t a lost cause. There are a number of ways to boost the oomph factor of your tresses. Take a look at the options below, all of which you can start implementing right away.

Detox and Volumize

Given that sebum and product buildup are common culprits behind flat hair, it makes sense to prioritize a hair detox. At the same time, you’ll want to add bounce and fullness to your locks. Simply put, you need the right hair care products tailored to your unique hair needs that can simultaneously do both — detox and volumize. Unfortunately, most hair care products on the market aren’t 100% customized to individual needs.

That’s where Function of Beauty’s fully customizable, made-for-you shampoo and conditioner come in. Understanding that hair care isn’t “one size fits all,” Function of Beauty lets you formulate your hair care routine to address your unique needs.

In fact, you can take our hair quiz and consider the following hair goals:

  • Soothe scalp: You can choose a formulation with aloe vera and salicylic acid to reduce buildup and help prevent flakes
  • Oil control: You can select a formulation with rosemary leaf extract and vitamin E to prevent excessive oil accumulation
  • Volumize: You can opt for a formulation with sweet almond extract and quinoa to rejuvenate limp, lifeless hair with noticeable volume and cleanse hair from buildup

For best results, shampoo from your roots to the midway length of your hair, conditioning only the ends. Doing so helps boost volume and maintain hydration without flattening the top of your head.

Change Up Your ‘Do

Aside from revamping your hair care routine, you’d be amazed at how the right haircut or styling method can help achieve the illusion of fuller, more voluminous hair.

Tease your tresses

One of the simplest tricks to quickly add volume to your hair is to tease it — aka backcombing. Simply comb your hair backward with a fine-toothed comb, using gentle up-and-down strokes to tease your hair strands into a cluster without making tangles. Spritz your head with a bit of volumizing hairspray to enhance the hold and tame any flyaways and frizz. You could also apply Function of Beauty’s custom hair serum on your hair ends and mid-shaft, which reduces frizz by 70% and is lightweight enough not to drag down your new ‘do.

Pro tip: Choose styling products with the label “soft hold” to avoid unwanted crunchiness.

Style strategically

Yes, a flat iron’s primary purpose is to straighten hair and keep away frizz, but that’s not the only thing it’s good for. With the right techniques in place, you can use a flat iron to create soft beachy waves and bouncy curls to add more volume.

Play with other styling tools as well — namely, curling irons and blow dryers. A curling iron helps you achieve luscious curls for instant volume. You can also splurge on a professional blowout or invest in a blow-dry brush (rather than a round brush and a blow dryer) to perfect salon-worthy blowouts at home.

To boost fullness, use hair volumizers like volumizing hairsprays, texturizing sprays, and thickening mousse. Just remember to cleanse thoroughly afterward with our custom shampoo specifically designed to tackle product buildup. (You can add “soothe scalp” to your hair goals when taking the quiz).

Pro tip: Blow dry your hair upside down and watch your mane magically puff up more than usual.

Get a haircut

A new haircut may be just the thing you need to instantly revitalize a flat mane.

Consult your hairstylist on which new ‘do will give the appearance of more body. To start the ball rolling, here are a few general tips:

  • Add layers but don’t overdo it: Work with your face structure to ensure the layers add texture and volume from the top (rather than bulk on the sides or ends). 
  • Keep it short: Opt for shoulder-length hair or shorter — if a chic pixie cut is too drastic for you, consider a trendy bob or a just-hits-the-shoulder trim, which can give the appearance of fuller hair.
  • Consider highlights: Contrasting shades add dimension to your mane, which not only keeps things interesting but also gives the illusion of greater hair volume.

If you want to feel like you’ve changed your hairstyle without actually visiting a hairdresser, try switching up your part, such as changing from a side part to a middle part. You’d be amazed at how this simple shift gives your hair an instant lift!

Fortify With Nutrients

To achieve fuller-looking tresses, make sure you’re also giving them enough nutrients. Along with following a healthy diet, incorporate specific hair products into your routine to fortify your strands. The key is to be mindful of the type of products you choose. For instance, if you’re on the lookout for nutrient-rich products that are suitable for flat hair, check out Function of Beauty’s custom hair mask. It’s an intensive deep conditioning treatment to help especially dry and/or damaged hair. Formulated with hair-healthy nutrients like Japanese sake extract and argan oil and customized according to your hair goals, the hair mask applies smoothly on wet hair and washes off in the shower. For best results, use it once or twice a week. 

Pro tip: Slather the mask onto the mid-shaft of your tresses to the ends (carefully avoiding the scalp), and run it through with a wide-toothed comb.

Flat Hair, Be Gone

Flat hair may have been the bane of your life until now, but it doesn’t have to remain that way. Once you’ve uncovered the root causes behind your flat hair — whether it’s too much scalp oil or using the wrong products — you’ve won half the battle.

Finish the good fight against limp-looking locks by reviewing your hair care routine to see if you need to replace any products. Interested in giving Function of Beauty’s custom hair care range a go? Check out our reviews. You can also try changing up your style since a new ‘do (in the hands of an experienced hairstylist) can help make your hair appear fuller and bouncier.