SIZE MATTERS
By Milajne, Founder & President of Zennkai — professional hair care across Metro Vancouver since 1984.
A great blow-out isn't about talent — it's about the brush. The right round brush, in the right size, does most of the work for you. Two things decide whether yours helps or fights you: the size of the barrel and the type of bristle. Match those to your hair length and the finish you want, and a salon-quality blow-dry at home stops being luck. Here's how to choose.
Round brushes are usually made with a metal or ceramic barrel, & work with the heat from your blow dryer by wrapping the hair around the brush to create curls & waves; much like a curling wand. Alternatively, a round brush helps to create tension in the hair to achieve a smoother, straighter style.
There are a couple things to take into consideration when choosing the right round brush for your hair & determining which size is going to work best for you. First, you want to consider the length of your hair, as well as the finished look or size of curl/wave you want to achieve.
A small round brush is most beneficial for styling a shorter fringe or bangs, or for creating volume & body if your hair is chin length or shorter. A 17mm round brush is great for pixie styles while a 23mmsize will work great for chin length styles or bobs. Keep in mind that the smaller the barrel, the tighter the curl will be for longer lengths.
Larger barrel round brushes are more ideal for smoothing & straightening, or creating waves in longer hair. A 32mm round brush is great for shoulder length hair, but it comes down to personal preference & some may prefer a larger brush like a 43mm round brush. A 43mm round brush is also ideal for hair that is beyond shoulder length, or creating bigger volume, & there are even larger 53-55mm round brushes for even more volume. The larger the barrel, the larger the curl or wave you will create. The same brush can be used for styling longer face framing layers or curtain bangs, but for shorter bangs or fringes, a smaller round brush is ideal.
Not only will the size of round brush make a difference in your blow dry, but so will the type of bristles that your brush has. The most common types of bristles include natural boar bristles, synthetic bristles (often nylon), or a combination of natural & synthetic.
Boar bristles are extra soft & gentle, & provide more tension with less breakage, creating a sleeker, smoother style with maximum volume. Boar bristles also produce more shine by distributing your hair’s natural oils from root to tip where your hair needs those oils most. Boar bristle brushes are suitable for all hair types, including those with straight or fine hair, sensitive scalps, & even thick hair that is wavy or curly to help smooth & minimize frizz. Natural bristle brushes may be more expensive but are known to last longer than synthetic options.
Synthetic bristles are generally made from nylon, but may be plastic as well. Nylon bristles tend to be more beneficial for detangling & reducing static. This type of brush is often best suited for extremely thick or course hair due to its detangling abilities.
Using a brush with a combination of natural & synthetic bristles means you will achieve the shine provided by the natural bristles as well as the detangling benefits of the synthetic. This type of bristle is generally great for everyone, but more so for fine hair or long hair. This is ultimately the best brush for most people if you are in doubt of which option is best for you, & is most commonly used by stylists within the salon.
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Beyond the Blowout: Matching Your Brush to Your Hair
A round brush is a blow-drying tool. But your everyday brush — the one you detangle and smooth with — should be chosen just as deliberately, and it comes down to the one thing most people get wrong: whether your hair is wet or dry.
Hair is at its weakest when it's wet. Water swells the strand and relaxes its internal bonds, so wet hair stretches and snaps far more easily than dry hair. That single fact decides which brush belongs in your hand:
Wet hair → Wet Brush Pro Flex Dry. Thin, flexible IntelliFlex® bristles bend around a knot instead of ripping through it — protective, pain-free detangling on fragile wet hair, with SofTips™ that massage the scalp as you go. Works on wet or dry hair, extensions, and wigs.
Dry hair → Dannyco Boar Bristle Paddle Brush. Pure boar bristles carry your scalp's natural oils down the strand to smooth the cuticle and add shine — the original anti-frizz step, no product required. Never use it on wet hair; the stiff bristles drag and break it.
FAQ
How do I choose the right round brush size?
Match the barrel to your hair length and the finish you want. A larger barrel creates a smoother, straighter, looser result and suits longer hair; a smaller barrel builds tighter curl and more volume and suits shorter hair. Ceramic-and-tourmaline barrels hold heat from your dryer to set the shape as you wrap the hair around them.
Should you use a boar bristle brush on wet or dry hair?
Dry hair, always. Boar bristles are relatively stiff, and hair is weakest when wet — water swells the strand and loosens its internal bonds, so a stiff brush dragged through wet hair stretches and snaps it. On dry hair, that same brush distributes the scalp's natural oils down the shaft to smooth the cuticle and add shine. For wet detangling, use a flexible detangling brush like the Wet Brush Pro Flex Dry instead.
What's the difference between a boar bristle brush and a wet brush?
They do different jobs. A boar bristle brush uses natural bristles to carry sebum from the scalp down the length of the hair, smoothing frizz and adding shine on dry hair. A wet brush uses thin, flexible bristles that bend around knots and glide through wet hair without snapping it. Boar is for dry-hair smoothing and shine; the wet brush is for pain-free detangling on fragile wet hair. Most people are best served owning both.
Are hair brushes good for your hair?
The right brush is good for it; the wrong one causes damage. A brush matched to your hair's state distributes natural oils, smooths the cuticle, reduces frizz, and detangles with minimal breakage. Mechanical damage comes from mismatches — brushing wet hair with a stiff brush, forcing a fine brush through thick knots, or using cheap plastic bristles that snag.
What's the best brush for frizzy hair?
A boar bristle brush on dry hair. The natural bristles pull the scalp's own oils down the strand and lay the cuticle flat — the mechanical version of an anti-frizz treatment. Pair it with the right anti-frizz products for structural frizz from humidity or damage — see our frizzy hair guide.