The human body undergoes complex transformations after death, prompting widespread curiosity about these post-mortem changes. Among the most enduring questions is what happens to hair, with a common belief suggesting it continues to grow. Scientific understanding, however, offers a different perspective on the fate of hair after death, distinguishing between actual biological processes and perceived alterations.
Debunking the Myth: Apparent Growth
The belief that hair continues to grow after death is a misconception. Hair growth, a complex biological process, requires a continuous supply of oxygen and glucose to hair follicle cells. When the heart stops beating, this vital supply ceases, and hair-producing cells die rapidly. True biological hair growth stops immediately upon death.
The illusion of continued growth stems from changes in the skin. After death, the body begins to dehydrate, leading to the shrinkage of skin and other soft tissues. As the skin recedes and tightens around the hair follicles, the hair shafts, previously embedded, become more exposed. This retraction creates the appearance of lengthened hair, though no new hair is produced. The body can lose a significant amount of water, which contributes to this noticeable skin shrinkage.
Actual Changes to Hair After Death
While hair does not grow, it undergoes distinct physical changes after death. Hair loses its natural moisture and oils, which are no longer produced by the body’s sebaceous glands. This absence of hydration causes the hair to become drier and more brittle. The hair’s texture may shift, appearing duller due to the lack of natural lubrication and the drying process.
Hair color can also change. Hair color is determined by two types of melanin pigments: eumelanin, which produces brown and black shades, and pheomelanin, responsible for red and yellow tones. After death, eumelanin breaks down more quickly than the more stable pheomelanin. This differential degradation can result in hair appearing reddish or lighter, especially in preserved remains.
Hair’s Remarkable Persistence
Despite the decomposition of most soft tissues, hair exhibits remarkable durability, often persisting for extended periods, sometimes centuries or even millennia. This resilience is primarily attributed to keratin, the fibrous protein that forms the main structural component of hair. Keratin’s robust nature stems from its complex molecular structure, characterized by strong disulfide bonds that provide significant resistance to physical and chemical degradation.
The resistance of keratin makes hair largely impervious to many common forms of microbial decomposition. While specific enzymes called keratinases can break down keratin, these are not widely produced by most microorganisms in typical decomposition environments. This inherent stability allows hair to outlast most other biological materials, making it a valuable source of information in forensic science and archaeology. Hair samples can provide insights into an individual’s diet, exposure to toxins, and even DNA, long after other bodily tissues have decayed.