Hair growth seems like a really simple process. After all, unless you’re going through hair loss, your hair just grows… right? Well, it’s a bit more complicated than that. There are actually four stages to the hair growth cycle, and each stage is unique and super important. So whether or not you realise it, your hair is going through a constant cycle of growing and falling out.
Each phase of the hair growth cycle handles a particular aspect of hair growth. To sum it up, the first three stages deal with the growth and maturation of hair strands, while the fourth stage is when you experience the “shedding” of old hair strands. So yes, it is totally normal to lose hair. In fact, on average, we lose about 100 hairs per day! As long as you’re not losing way more than that, you’re in the clear and your hair growth cycle is running smoothly.
Stage 1: Anagen
During the anagen stage of hair growth, the hair is continuously growing — this is the active growing phase. There is lots of activity in the hair bulb including the production of melanin, which is the pigment that gives hair its colour. How long this phase lasts depends on the location of the hair on your body. For your eyebrows, this stage lasts 2 to 3 months, but for the hair on your scalp, it can last for 2 to 5 years.
Stage 2: Catagen
During the catagen phase, the follicle stops producing hair and melanin. This is what is known as a “transient phase” of the hair growth cycle, which basically means it doesn’t last very long. The base of the hair starts to move upwards towards the top of the skin. On average, this stage lasts for 2 to 4 weeks.
Super interesting to note, is that the hair growth cycle is stopped at this stage during pregnancy. This means more hair grows and no hair falls, so those who are expecting their own bundle of joy will often have a fuller head of hair. However, after pregnancy, the cycle resumes and that extra hair is lost, which is why it can feel like severe hair loss after pregnancy.
Stage 3: Telogen
The telogen stage can be seen as the resting stage of the hair growth cycle. At this point, the existing hair is no longer growing and a new anagen hair strand starts to grow from the base of the follicle. The telogen stage is relatively short and only lasts about 3 to 4 months.
Stage 4: Exogen
At this stage, the new anagen hairs push out the old telogen hairs in a process called exogen or hair shedding. This process is generally pretty quick, and as we mentioned above, can push out about 100 hairs per head.