How Fast Can Hair Grow?

Whether you're hoping for a quick recovery from a bad haircut, want to achieve a certain look for a special occasion or are just curious about the process that keeps us all scurrying back to the stylist for trims and touch-ups, it can be helpful to know exactly how---and how fast---hair grows. Unfortunately, the answer is pretty much the same for everyone, which means there's no secret formula to make your hair grow faster. Understanding how hair grows, however, can help you set realistic expectations and take steps to support natural, healthy hair growth.

How Hair Grows

• Hair grows in phases. During the first phase, called anagen, hair grows an average of a half-inch per month, although up to an inch per month is sometimes possible. Anagen lasts anywhere from two to eight years, which is why some people can grow hair up to four feet long, while others top out at around one foot.

  Following anagen, a transitional phase called catagen occurs for two to four weeks. In catagen, the hair stops growing, and the follicle shrivels. For most people, 10 to 15 percent of all hair is in the catagen phase.

  During the last phase, telogen, hair remains attached to the follicle but no longer grows. Telogen lasts for two to four months, and then anagen begins again, pushing out the old hair to make way for new growth. We tend to lose 50 to 100 hairs a day, usually in the shower or during combing or brushing, due to this natural process.

Hair Fibers

• The keratin proteins that make up our hair are also found in our fingernails and toenails, and in the claws, hooves, horns and beaks of many animals. Each hair has three layers: the cuticle, cortex and medulla. The medulla is at the center and has a reflective quality that makes hair shine and gives it tone. Surrounding the medulla is the cortex, a thick layer that contains melanin, which determines the color of the hair. The cortex's shape is also responsible for making hair straight, wavy or curly. Enclosing the cortex, the cuticle is a thinner, colorless coating that protects the hair.

Hair Follicles

• Hair is anchored beneath the skin by follicles, which surround the hair root and power its growth. Sebaceous glands connected to the follicle secrete an oil called sebum that moisturizes and protects hair and skin. Muscles connected to the follicle can cause hair fibers to stick up, an effect you're familiar with if you've had goosebumps.

Hair Growth Misconceptions

• Many people believe hair grows faster when you cut it. This is not true, but there are a couple of reasons why it might seem to be. Hair fibers have tapered tips, which help them push through pores in the skin during early growth. Eventually keratin builds up, making the hair thicker and longer. Cutting a hair removes its tip, leaving only the thickest part of the hair, which can make cut hair seem thicker and healthier.

  Cut hair may also seem to grow faster because growth is easier to spot in someone with shorter hair. For example, close-cropped hair could double its length in only a month or two, while long hair could go for months without a trim. This trick of perception can be especially powerful when someone changes from a long hairstyle to a short one and may suddenly need more frequent haircuts to maintain the same look.

Ways to Encourage Hair Growth

• Products, services and techniques to make hair grow are everywhere these days, but do they really work? There is no miracle solution to shorten the path to long, luxurious hair, but you can take some steps to support your hair's natural growth.

  A balanced diet and regular exercise can help you stay healthy overall, which will allow your hair to be its best. Some people also try to encourage hair growth by supplementing their diet with vitamins and minerals, such as B-vitamins and beta-carotene. You should consult a doctor or dietitian before doing so, though. It also helps to take good care of your hair through regular hygiene and grooming. For example, massaging the scalp thoroughly when you wash your hair can encourage blood flow and stimulate your follicles.

  When it comes to more unusual or invasive treatments, be sure to do your research and speak with a hairstylist, pharmacist or doctor, as appropriate, before taking the plunge.