Carnosine (B-alanyl-L-histidine) is a di-peptide (a combination of two amino acids) composed of histidine and alanine. It is found naturally in relatively high concentrations in your body tissues, most notably in skeletal muscles, heart muscles, nerve tissues, and the brain. Carnosine is referred to as "the longevity nutrient" because it has been proven to protect and extend the functional life of your body's key building blocks (cells, proteins, DNA, and lipids). It can delay aging and incite cellular rejuvenation in human fibroblasts and is very well-known for its antioxidant, antiglycator, and metal chelator properties.

Characteristics
Carnosine exihibits three major properties:

• Antioxidant - Carnosine stabilizes and protects the cell membrane. It prevents lipid peroxidation within the cell. It acts as a water-soluble free radical scavenger, blocking free radicals from entering the tissues. Failing to have blocked these free radicals as a first line of defense, Carnosine remains active in fighting "second wave chemicals" (dangerous by-products of free radical reactions). This action prevents damage to lipids, enzymes, and DNA, which when not controlled, can lead to atherosclerosis, joint inflammation, cataract formation, and accelerated aging in general. By neutralizing these compounds, Carnosine sacrifices itself in order to protect the amino acids on the protein molecules of your body. 

• Antiglycator - Carnosine opposes glycation. Glycation is a reaction that takes place when simple sugar molecules such as fructose or glucose become attached to proteins or lipid fats without the moderation of an enzyme. This reaction disrupts normal metabolic pathways and accelerates formation of AGEs (Advance Glycosylation End-products). AGEs are abnormal, cross-linked oxidized products that can cause extensive damage to your body. Carnosine blocks this deleterious reaction, protecting against cross-linking of proteins, cross-linking of proteins to DNA molecules, and formation of other abnormal proteins, which are all contributing factors to increased health risks and the aging process.
  
  Asides from inactivating aldehydes and ketones and reducing protein glycosylation and AGEs formation, Carnosine also binds to already formed AGEs and ameliorates them. AGEs are removed by scavenging macrophages (immune system cells) which carry special receptors called RAGEs (Receptor for Advanced Glycation End-products). Carnosine facilitates this process of elimination by helping macrophages to better recognize the AGE molecule. Because of its anti-glycosylation actions, Carnosine has been found useful in treating or preventing diabetic complications such as cataract, neuropathy, and kidney failure. Other anti-glycators like aminoguanidine may also protect against glycosylation but not as effectively as Carnosine. Some amino acids (arginine or lysine) are also able to combine with glucose in order to eliminate dangerous AGEs, but the end-product of this reaction is mutagenic (may cause cancer). However, Carnosine's combination with glucose is non-mutagenic. 

• Metal Chelator - Carnosine can chelate divalent metal ions (combine with excess metals in the cells and blood stream, so the liver and kidneys can excrete them). Due to this property, Carnosine helps your body reap a greater number of health benefits such as dilating constricted arteries, reducing high blood pressure, diminishing free radical activity, improving uptake of oxygen to the cells, relieving pain in the extremities, increasing blood vessel elasticity, enhancing blood flow, and stimulating enzyme activity.

Functions of Carnosine

• Repairs Cell Damage - Carnosine has the remarkable capacity to rejuvenate cells approaching senescence (the end of the life cycle for cell division) by restoring normal appearance and extending cellular lifespan. It interacts with several free radical species including singlet oxygen, hydrogen peroxide, and peroxyl and hydroxyl radicals. Carnosine is able to inhibit radical-induced cellular damage induced by iron, copper, and zinc.

• Increases Muscle Strength - Carnosine is found primarily in type II muscle fibres. These are the "fast-twitch" fibres that are important for explosive movements such as sprinting and weight training. Increasing muscle Carnosine concentrations increases intramuscular hydrogen ion (H+) buffering capacity. The production of H+ is the result of energy release. Carnosine extends muscle endurance by taking away these Hydrogen ions to prevent your muscles from becoming too acidic during times of stress. High-intensity performance also causes oxidative stress in the muscles; the free radicals produced through high intensity muscular activity cause lipid peroxidation and carbonylation of proteins and phospholipids. This causes proteins to break up in a process known as proteolysis, which is later associated with the toxic process leading to cell aging and fatality. Carnosine can combat these reactions when there is enough of it stored in the muscles. It also plays a role in activating  enzymes responsible for generating muscle contractions and serving as an intramuscular buffering agent to retard accumulation of lactic acid.

• Protects DNA from Harm - Carnosine can protect cellular DNA from oxidative damage that accumulates with age. Laboratory studies indicate that Carnosine has the ability to protect cells against oxidative stress as well as to increase their resistance toward functional exhaustion and accumulation of senile features.

• Accelarates Wound Healing - Carnosine has the amazing ability to rejuvenate connective tissue cells and to expedite wound healing. Your skin has an ally in L-Carnosine which provides constant skin renewal every after exposure to sun's radiation and physical trauma (cuts or burns). As you age, the dermis (the inner skin layer) undergoes a normal loss of structural integrity. Fibroblasts, the carpenter cells that build connective tissue, are reduced in number. Collagen fibers may become damaged as the matrix that connects cells together experiences wear and tear, manifested in wrinkles, dryness, inconsistent skin texture and coloring, and sagging skin. Carnosine supports the healthy function of fibroblasts and assists the body in preserving normal protein structures. Carnosine prevents, reduces, and reverses the formation of such glycated end products, and also breaks protein-sugar bonds to enable actual reversal of skin disorders associated with aging.

• Helps Protect your Brain - Carnosine protects the microvasculature of your brain from plaque formation that leads to senility and Alzheimer’s disease. It exerts neuroprotective activity that prevents neurodegeneration and accumulation of senile features and protects brain function against oxidative injury. Carnosine has been successfully used to treat strokes and Parkinson's disease.
  

How is Carnosine Produced?
Carnosine is produced by a process involving the enzyme carnosine-synthetase which bonds the amino acids alinine and histidine. This process occurs mainly in muscles and brain. It is kept in equilibrium by the carnisinases, enzymes specifically aimed at inactivating carnosine in the tissues or in the blood. High concentrations of Carnosine are present in long-lived cells such as in neuronal tissues and muscles. It is high in actively contracting muscles and low in cases of muscular disease. Carnosine concentration directly correlates with your maximum lifespan!

Carnosine levels decline with age. Researchers report that with increasing age, the antioxidant effect of Carnosine decreases by half. Reduction in muscle carnosine concentration may be a cause of the age-related decline in muscle mass, strength, and function. A low concentration of Carnosine is found in weakened muscles, such as those affected by muscular dystrophy. In fact, people who suffer from a neuromuscular disease exhibit a 63% decline of muscle concentrations of Carnosine, from the years 10 to 70. Stress and trauma also cause a reduction in Carnosine levels.