There are 2 types of bristles for brushes—whether for your hair or for your makeup: Natural and synthetic. Of course, there are fans of each type for different reasons—but neither type is better than the other. As with anything, it is a matter of preference—based upon price, availability, effectiveness, comfort, and even belief. The best way to find out which you prefer is to try each and decide what works best for you.
Natural brushes, just as the name indicates, are made of materials found in nature. This includes animal hairs, such as boars, squirrels, and goats. These brushes tend to be a little more pricey. Some people who support and believe strongly in animal rights may choose not to use natural brushes due to, in some cases, the animals not being raised in good conditions. It is said that natural brushes hold pigment a little better than synthetic brushes, and this is especially true of powders like eye shadow, powder blush, and loose powder. This is because the hairs tend to spread out from each other more and do not move as flexibly as synthetic brushes. They are also a little more difficult to clean than synthetic brushes. I have a Mason Pearson natural bristle hair brush that I heard rave review about, so I decided to order one. I will say that it smoothes my hair better than a synthetic brush and I often use it to “polish” off a hairstyle, if my hair is worn down, or up in a ponytail. It’s important to keep natural brushes away from oils and sunlight, and keep them dry. I clean mine about once a month, with the cleaning brush that comes with it, and per the directions for cleaning.
Synthetic brushes are man-made, usually from materials such as nylon or polyester, and they are dyed usually a cream to brown color. These brushes tend to be less expensive than natural bristles and you can find them just about anywhere in a range of prices and styles. They are generally easier to clean (with makeup remover or soap and water) because they are coated and do not absorb pigment as well as natural brushes. It is said that synthetic brushes are best for cream and liquid makeup application, such as foundation, concealer, or cream blush. The hairs tend to come together better for a more even finish. They do not pick up pigment or apply powder as well as natural brushes, however. I have a great synthetic foundation brush that I use, and it does not absorb as much of the product as a sponge would (because lord knows that stuff is expensive and it needs to be used sparingly!)
In my beauty arsenal, I have both natural and synthetic brushes. I have bought cheap brushes and expensive ones—sometimes it is based purely on availability. For example, I was looking for an angled blush brush not too long ago, and I could not find one ANYWHERE in stores, and I looked hard. I finally found one at Sephora that was exactly what I was looking for. But, had I found one cheaper somewhere else, I would have probably bought it. I subscribe to the notion that if it works for what I need it for, then it’s good, regardless of if it is natural or synthetic. Different strokes—er, that is, brush strokes, for different folks!