Vitamin C and L-Lysine supplement by Onnit provides the antioxidant power of vitamin C to neutralize free radicals along with the essential amino acid L-Lysine. Since lysine is an essential amino acid it can’t be made by your body therefore you must get it through your diet. Lysine is important for the production of a wide range of proteins including antibodies, enzymes, and collagen. It is involved with calcium absorption and maintaining healthy blood vessels. Lysine also plays an important role in balancing excess amounts of the amino acid arginine. Excess arginine has adverse affects on the immune system.

Vitamin C

Since we have no gene that codes for vitamin C we must take it in through our diets. Vitamin C is an electron donor and water-soluble so this vitamin is located in any compartment of the body that contains water. Studies indicate that diets high in fruits and vegetables are associated with a decreased risk of cardiovascular disease, stroke, and cancer, and provides for increased longevity.

Interestingly, vitamin C is synthesized in most mammals but unfortunately not humans. We are lacking the enzyme gulonolactone oxidase which is required for making vitamin C. The gene coding for gulonolactone oxidase has mutated a number of times rendering it a nonfunctional enzyme. A clinical sign of a vitamin C deficiency is scurvy which is a serious situation which needs to be remedied quickly or death ensues.

Since vitamin C is an electron donor it acts as a reducing agent. This vitamin donates 2 electrons from a double bond that is found between the second and third carbon of this 6 carbon molecule. It’s antioxidant properties come from the fact that it can donate electrons preventing other compounds from being oxidized. As with a number of other antioxidants, vitamin C becomes oxidized in the process of donating its electrons. Vitamin C donates 1 electron at a time becoming a free radical that is actually somewhat stable and relatively unreactive. Another free radical can interact with this vitamin donating an electron returning vitamin C to its reduced state and ready to go again.

When vitamin C loses an electron it is referred to as ascorbyl radical and when it loses a second electron it forms dehydroascorbic acid. Both these forms of vitamin C can interact with molecular oxygen, superoxides, hydroxyl radicals, hypochlorous acid, reactive nitrogen species and minerals such as iron and copper. Nevertheless, once both forms of vitamin C are present it can be reduced back to a reduced state by enzymes and glutathione however, reduction is not complete so vitamin C is continually lost and therefore has to replenished by diet. Unfortunately, one break down product of vitamin C is 2,3-diketogulonic acid which is further broken down to xylose, xylonate, lyxonate, and oxalate. Oxalate can result in the formation of kidney stones in some individuals when excessively produced.

Vitamin C also acts as an electron donor for 8 different enzymes. Three of these enzymes are involved in the hydroxylation of collagen. Hydroxyl (OH) groups are added to the amino acids proline or lysine in the collagen molecule increasing the stability of the collagen molecule. Two other enzymes that vitamin C reduces are involved with the synthesis of carnitine. Carnitine is important for the transport of fatty acids into the mitochondria for the production of ATP. The other 3 enzymes that are activated by vitamin C are involved with the biosynthesis of the neurotransmitter norepinephrine from dopamine, adding amide groups to peptide hormones, and modulating tyrosine metabolism.

Vitamin C is able to protect the outer surface of your cells as well as lipids, protein and DNA inside your cells as well as in your blood stream. Lipids, membrane lipids, and lipids that circulate in blood such as those found in LDLs (low-density lipoproteins) can interact with reactive oxygen species (ROS) generating lipid peroxidation. As this process continues free radicals can accumulate rapidly. Vitamin C comes to the rescue by inhibiting lipid peroxidation returning these lipids to their normal state. This is important for the prevention of atherosclerosis (plaque). When LDLs become oxidized they activate a local adhesion factor that is expressed by endothelial cells of the vasculature. This in turn attracts macrophages. Macrophages accumulate more oxidized LDLs which become embedded into the vascular wall. It has been suggested that vitamin C can inhibit the entire process slowing down the deposition of plaque.

Proteins can also become oxidized. Certain amino acids are more prone to oxidation such as cysteine, methionine, arginine, proline, threonine, tyrosine, histidine, tryptophan, valine, and lysine. Proteins that contain these amino acids are easily oxidized and can accumulate rapidly. By reducing the radical initiators, vitamin C can prevent protein oxidation and accumulation.

DNA is susceptible to damaging oxidative reactions inducing mutations. Of major concern is the attack of oxidants to individual DNA nucleotides. It turns out the the base guanine is most susceptible to oxidative attack. Vitamin C has the ability reduce the formation of radical guanine species directly. Vitamin C also protects proteins that repair DNA in the nucleus.

You might be wondering since vitamin C is water-soluble how it gets inside cells since their membranes are made up of lipids (fats). This means that vitamin C can’t enter by passive diffusion because it can’t just plow through the membrane on its own. It has to have transport systems that carry it in. When vitamin C donates 2 electrons it become dehydroascorbic acid (DHAA), it can be transported through the plasma membrane by way of facilitated diffusion. This channel may be glucose-sensitive or insensitive. This type of transport does not require the use of energy in the form of ATP. There are two other ways vitamin C can enter a cell which includes the use of secretory vesicles as well as active transport. Secretory vesicles can carry vitamin C inside themselves and fuse with the plasma membrane dumping their contents directly into the cell. Active transport involves the use of a sodium-dependent vitamin C channel that requires ATP to drive it. Research demonstrates that these vitamin C transport systems work differently depending on any disease states that are present including the aging process. That means that under certain conditions vitamin C may not be able to enter cells.


L-lysine is an essential amino acid that happens to be the second most limiting amino acid. In other words, if you have very little lysine around, that slows down protein synthesis as lysine is found in all proteins and in some cases is the major amino acid in a protein such as collagen. Lysine is also important for calcium absorption, antibody production, maintaining healthy vasculature, and repairing tissues.

Good sources of lysine include red meat, lamb, pork, poultry, soybeans, black beans, green beans, kidney beans, navy beans, snap beans, and milk. Proteins that are found in grains, cereals and their products contain very little lysine. However, wheat germ contains a high concentration of lysine and a good way to supplement your diet. Supplementation of lysine has gained some popularity due to its ability to decrease the recurrence rate of herpes simplex viral infections. It turns out that the proteins found in the herpes virus are rich in L-arginine. Studies done in tissue culture have demonstrated that culture medium that has a high ratio of arginine to lysine increases viral replication. However, when you reverse the situation such that the ratio of lysine to arginine is high, viral replication is inhibited. It is believed that lysine out competes arginine in protein synthesis causing the herpes virus to replicate incorrectly. This in turn shortens the frequency and severity of outbreak and in fact may stop them altogether.

Lysine as an essential amino acid is important for body growth and regeneration. It is important in the healing of wounds. It is a building block of carnitine which is important for the importation of fatty acids into the mitochondria for the production of ATP. It is a major amino acid component of collagen which is important for skin, muscle, bones, hair, teeth, tendons, and ligaments. Lysine has been reported to aid in the absorption of calcium in the intestine and therefore may be important for individuals who have osteoporosis. Lysine participates in the formation of glucose and glycogen as well as lipids.

Suggested Readings:

Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention

The biology of lysine acetylation integrates transcriptional programming and metabolism

Lysine Requirement and its Effect on the Body Composition of Oreochromis niloticus Fingerlings