But it's not just the individual cells we have to worry about. In a frozen state, tissues are generally biologically stable. Biochemical reactions, including degeneration, are slowed at ultra-low temperatures to a point where they are effectively halted. Nonetheless, there is a risk that frozen structures can experience physical disruption, such as hairline cracks. Then, upon thawing, temperature fluctuation causes a series of problems. Tissues and cells can be damaged at this state. But it also has an effect on our overall "epigenetics" – how environmental factors and lifestyle choices influence our genes – by causing epigenetic reprogramming. However, antioxidants and other substances can help aid post-thaw recovery and prevent damage.