From the Guidelines
The anagen phase of hair growth typically lasts around 2-6 years for scalp hair, during which hair grows at a rate of approximately 1 cm/month, as noted in the study by 1. The duration of the anagen phase varies significantly depending on body location, with scalp hair having the longest anagen phase, while eyebrow or arm hair may only remain in anagen for a few months.
- Genetics, age, health status, and hormones all influence the duration of the anagen phase, with some people naturally experiencing longer growth phases than others.
- As we age, the anagen phase typically shortens, which is why older adults often have thinner hair.
- Various health conditions and nutritional deficiencies can also shorten this phase, potentially leading to hair thinning or loss, as discussed in the context of chemotherapy-induced alopecia by 1. The study by 1 also highlights the importance of the anagen phase in hair growth, particularly in the context of treatments for androgenetic alopecia, where the anagen phase is a key factor in determining the effectiveness of treatments such as platelet-rich plasma (PRP) therapy.
- The use of PRP therapy has been shown to increase hair density and promote hair growth, particularly when combined with other treatments such as minoxidil, as noted in the study by 1. However, it is essential to consider the potential side effects and limitations of such treatments, as well as the individual variability in response to treatment, as discussed in the study by 1.
- Ultimately, the anagen phase of hair growth is a critical factor in determining the effectiveness of treatments for hair loss, and understanding its duration and variability is essential for developing effective treatment strategies.
From the Research
Anagen Phase of New Hair Growth
- The anagen phase is the active growth phase of hair growth, during which the hair grows rapidly 2.
- The length of the anagen phase varies from person to person, but it typically lasts between 2-6 years 2.
- Factors such as genetics, hormones, and age can influence the length of the anagen phase 2.
Hair Growth Cycle
- The hair growth cycle consists of three phases: anagen, catagen, and telogen 3.
- The anagen phase is followed by the catagen phase, a short transitional phase that lasts about 2-3 weeks 3.
- The telogen phase is the resting phase, during which the hair is released from the follicle and falls out 3.
Treatments for Androgenetic Alopecia
- Treatments such as minoxidil and finasteride can help promote hair growth and extend the anagen phase 4, 3, 2, 5, 6.
- Minoxidil can help increase hair density and diameter, while finasteride can help reduce dihydrotestosterone (DHT) levels and slow follicular miniaturization 4, 3, 2, 5, 6.
- Combination therapies, such as oral minoxidil and finasteride, may be more effective than monotherapies in promoting hair growth 5.
Frequency of Anagen Phase
- The frequency of the anagen phase is not explicitly stated in the provided studies, but it is known that the anagen phase can last anywhere from 2-6 years 2.
- The anagen phase can be influenced by various factors, including genetics, hormones, and age 2.
- Treatments such as minoxidil and finasteride can help promote hair growth and extend the anagen phase, but the frequency of the anagen phase may vary from person to person 4, 3, 2, 5, 6.