There's no single age limit that definitively stops hair growth. However, the rate of hair growth changes significantly throughout life.
Peak Hair Growth and Decline
Hair growth is fastest between the ages of 15 and 30. After this period, hair growth gradually slows down. This reduction in growth contributes to hair thinning experienced as people age. Several sources confirm this observation. [This is supported by multiple sources, including WebMD, RHRLI, and Medical News Today.](https://www.webmd.com/healthy-aging/maintain-hair-growth-after-50, https://rhrli.com/blog/3-ways-your-hair-changes-with-age/, https://www.medicalnewstoday.com/articles/326764)
Individual Variation and Factors Affecting Hair Growth
While there's no absolute age cutoff, individual factors heavily influence hair growth. Genetics, overall health, hormonal changes, and even stress play crucial roles. Some follicles may cease functioning altogether as one ages, contributing to hair loss or thinning. A Quora thread discussing this topic highlights the individualistic nature of hair growth, especially in later life. (https://www.quora.com/What-is-the-maximum-age-for-hair-growth-in-women)
Maximum Hair Length vs. Growth Cessation
It's important to distinguish between the maximum length a hair can reach and the complete cessation of hair growth. Hair has a growth cycle; the anagen phase (growth) varies individually from 2 to 7 years (and even longer in some cases). (https://www.reddit.com/r/askscience/comments/5vc26w/is_there_a_maximum_length_that_a_human_hair_can/) Once a hair reaches its terminal length, it enters the telogen phase (resting), eventually shedding, and being replaced. This process continues throughout life, although the rate of growth and the overall number of functioning follicles decrease with age.
Age and Hair Transplant Suitability
The suitability for a hair transplant isn't solely determined by age. Instead, it depends on factors like the individual's hair loss pattern, overall health, and expectations. (https://www.drpetervila.com/blog/what-is-the-age-limit-for-a-hair-transplant/)
In summary, while hair growth slows with age and some follicles become inactive, there is no definitive age at which hair growth completely stops. The rate of growth and the overall thickness of hair are impacted by various factors, resulting in individual variations.
