What to Combine L-Lysine With

L-lysine is rarely sold “solo”: manufacturers eagerly add vitamin C, zinc, herbal extracts, or arginine to it. Some of these combinations have a logical biochemical rationale, others only a marketing one. The editorial team analyzed what it really makes sense to combine lysine with, which combinations are best avoided, and how not to overdo the total doses.

Principles of combining amino acids and micronutrients

Before discussing specific combinations, it is worth outlining the general rules. Amino acids are absorbed in the small intestine with the help of transport proteins, and these transporters are often shared by several structurally similar molecules. Lysine belongs to the cationic (basic) amino acids together with arginine and ornithine, so it competes most strongly precisely with them.

Vitamins and minerals, on the contrary, most often act as cofactors of enzymes that convert lysine into other compounds. Here a combination can make sense, but only when there is a real deficiency of the cofactor in the body. If there is enough vitamin C or iron, an additional portion of them will not speed up the processes.

The third principle is the total dose. Lysine is contained in proteins, amino acid complexes, BCAA blends with added essential amino acids, and collagen products. A person taking several supplements at once can, without noticing it, significantly exceed the intended amount.

And finally, a combination should be appropriate for a specific goal. For herpes prevention, connective tissue support, or correcting a vegetarian's diet, the “ideal pairs” will be different, so there is no universal formula.

Lysine and vitamin C: collagen and carnitine

The most biochemically justified combination is lysine and vitamin C. In collagen synthesis, the enzyme lysyl hydroxylase converts some of the lysine residues into hydroxylysine. This enzyme, like prolyl hydroxylase, requires ascorbic acid and iron. Without vitamin C, collagen fibers are formed defective — this is exactly how scurvy develops.

Vitamin C is also needed for the synthesis of carnitine from lysine and methionine. Carnitine transports fatty acids into the mitochondria for oxidation, and its formation in the body depends on several cofactors: vitamin C, vitamin B6, iron, and niacin (Rebouche, 1992).

In practice, a person with an ordinary diet containing vegetables and fruit rarely has a vitamin C deficiency. Therefore, adding 100–500 mg of ascorbic acid to lysine is more of an “insurance” than a mandatory condition. There is no harm from such a combination, provided there are no contraindications to vitamin C, such as a tendency to oxalate kidney stones.

For athletes interested in supporting tendons and ligaments, lysine is not the main “collagen” ingredient. A study by Shaw and colleagues (2017) showed that taking vitamin C-enriched gelatin before exercise increased markers of collagen synthesis. Gelatin already contains lysine, glycine, and proline in the right proportions.

Lysine, zinc, and calcium

The combination of lysine with zinc is a classic of “lips and immunity” products. Zinc is necessary for the normal functioning of the immune system, and its deficiency is associated with more frequent infections. The manufacturers' logic is simple: combine lysine, which may reduce the frequency of herpes recurrences, with zinc, which supports immunity.

There is little direct high-quality research proving the advantage of the “lysine + zinc” combination over each component separately. Therefore, such a combination should be regarded as convenient but not as proven synergistic. It is important to watch the zinc dose: prolonged intake of high doses can cause copper deficiency.

With calcium the situation is more interesting. Civitelli and colleagues (1992) showed that lysine increases intestinal calcium absorption and reduces its excretion in urine. Theoretically this makes the combination of lysine with calcium beneficial for people with insufficient calcium intake.

However, there is a flip side: in people prone to hypercalcemia or calcium kidney stones, such enhancement is undesirable. People who already take high doses of calcium and vitamin D should add lysine only after consulting a doctor.

Lysine and arginine: partners or competitors

Lysine and arginine are the most controversial pair. On the one hand, they are often combined in products for “growth hormone” or “stress reduction”. On the other, they compete for the shared transporters of cationic amino acids, and high doses of one can affect the level of the other in the blood and tissues.

A study by Smriga and colleagues (2007) showed that a combination of L-lysine and L-arginine over the course of a week reduced anxiety measures and basal cortisol in healthy people under stressful conditions. The effect was observed precisely for the combination, so transferring it to lysine alone is incorrect.

As for growth hormone, an early study by Isidori (1981) found an increase in its level after combining both amino acids, but later work with athletes did not confirm this. Thus, there are no compelling grounds to buy such a combination for “natural hormone stimulation”.

If, however, you take lysine for herpes prevention, the logic is the opposite: in laboratory studies the virus uses arginine for replication, so simultaneous intake of high doses of arginine in nitric oxide donors and pre-workout complexes contradicts the goal. People prone to herpetic eruptions should pay attention to the composition of such products.

Lysine in an athlete's diet: protein, iron, collagen

For most people who train, the main source of lysine is ordinary food and proteins. Whey, casein, and egg proteins contain a lot of lysine, so a separate supplement on top of them is mostly unnecessary. If you still want to take lysine, you can simply add it to a protein shake — this is convenient and masks the bitter taste of the hydrochloride.

• Plant proteins:pea protein is rich in lysine, whereas rice protein contains less of it; a blend of pea and rice partly compensates for this difference.
• Collagen peptides and gelatin:contain lysine, hydroxylysine, glycine, and proline, but are poor in tryptophan, so they are not a complete protein.
• Iron:according to the review by Rushton (2002), in women with hair loss and low ferritin, adding lysine to iron preparations improved the response; iron should be taken only with confirmed deficiency.
• Creatine, beta-alanine, caffeine:there are no known interactions with lysine, they can be taken independently.

As for timing, there is no clear evidence of an advantage of morning or evening intake. In herpes studies, the total daily dose was divided into several intakes with food, which reduces the risk of stomach discomfort. It is reasonable to apply this approach in other cases as well.

Vegetarians and vegans should build their diet so as to combine grains with legumes. Classic pairs — rice with beans, bread with hummus, buckwheat with lentils — provide a better amino acid profile than any single source alone.

Editorial conclusions

The most biochemically logical combination is lysine with vitamin C, since ascorbic acid is needed for the synthesis of collagen and carnitine. The combination with zinc is convenient, but its synergy is not proven.

Lysine enhances calcium absorption, which can be a plus or a minus depending on the state of health. Iron makes sense to add only with confirmed deficiency.

Lysine and arginine compete for transport; for herpes prevention, high doses of arginine are undesirable, and the effect of the combination on growth hormone is not confirmed.

We also recommend familiarizing yourself with our articles “L-Lysine: Available Forms and Which to Choose”, “Myths About L-Lysine” and “Glycine: What It Is and How It Works”.

References

1. Rebouche CJ. Carnitine function and requirements during the life cycle. FASEB J. 1992;6(15):3379–3386.
2. Civitelli R, Villareal DT, Agnusdei D, et al. Dietary L-lysine and calcium metabolism in humans. Nutrition. 1992;8(6):400–405.
3. Smriga M, Ando T, Akutsu M, et al. Oral treatment with L-lysine and L-arginine reduces anxiety and basal cortisol levels in healthy humans. Biomed Res. 2007;28(2):85–90.
4. Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017;105(1):136–143.
5. Rushton DH. Nutritional factors and hair loss. Clin Exp Dermatol. 2002;27(5):396–404.
6. Isidori A, Lo Monaco A, Cappa M. A study of growth hormone release in man after oral administration of amino acids. Curr Med Res Opin. 1981;7(7):475–481.
7. Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica. 1987;175(4):183–190.