What is the decomposition time of hair?

August 12, 2023
min read

Short answer

Hair has a decomposition time of several years to decades.


Hair is composed of a protein called keratin, which makes up the majority of its structure. When hair decomposes, it goes through several stages of breakdown. Initially, the outer layer of the hair, known as the cuticle, begins to open up, exposing the inner layers to the surrounding environment. This process is accelerated by factors such as sunlight, moisture, and temperature changes. As a result, the hair becomes more brittle and loses its elasticity.

The next stage of decomposition involves the breakdown of the cortex, the middle layer of the hair shaft. The cortex contains most of the pigment responsible for the hair's color, as well as the structural fibers that give hair its strength and flexibility. Enzymes and bacteria present in the surroundings start breaking down these fibers. The hair becomes weaker and starts to lose its color, gradually turning yellow or gray. The breakdown of the cortex also causes the hair to become increasingly fragile and prone to breaking.

Ultimately, the final stage of decomposition involves the complete breakdown of the keratin protein. Bacteria and fungi play a significant role in this process, as they release enzymes that break down the remaining protein chains. The hair loses all its structure, and its physical properties deteriorate further. Eventually, the decomposed hair is reduced to small fragments, and the remaining components blend with the surrounding environment. Factors such as humidity, temperature, and the presence of microorganisms can influence the rate of hair decomposition, which can vary significantly in different environments.

Is it possible to recycle hair?

Intresting facts

  • Hair is composed mainly of a protein called keratin, which is highly resistant to decomposition. This is why hair can persist for long periods of time, even after the rest of the body has decomposed.
  • The rate of hair decomposition depends on various factors such as environmental conditions, exposure to sunlight, humidity, and the presence of microbes. For instance, hair buried in moist soil may decompose faster than hair exposed to the air.
  • In the early stages of decomposition, hair may lose its color due to the breakdown of pigments. This leads to a loss of the characteristic hair color, turning it gray or white.
  • Over time, the structure of the hair shaft breaks down, causing it to become brittle and easily fragmented. This is especially true when exposed to UV radiation and oxygen.
  • Hair is often used as an indicator of postmortem interval (PMI) in forensic investigations. By assessing the stages of decomposition of hair, forensic experts can estimate how long a body has been deceased, aiding in criminal investigations.

Summary and final thoughts

The decomposition time of hair varies depending on certain factors. In general, hair takes a long time to decompose, as it is composed of a protein called keratin which is resistant to decay. Under optimal conditions, it may take several years for hair to break down completely. However, the rate of decomposition can be influenced by factors such as environmental conditions, burial depth, presence of microorganisms, and other factors that can accelerate or slow down the decomposition process. Overall, hair is a relatively durable material that can persist for a significant amount of time even after death.

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