High-lysine (or just lysine) is one of the essential amino acids that is a necessary part of your diet for overall good health. In this article, we explain what is Lysine, what are its benefits and side effects, what are some high-lysine foods, and how lysine can be used to treat things like cold sores and anxiety.

Lysine is a building block of many essential proteins that play important roles in building up immunity to fight diseases and increasing appetite and digestion. It also increases calcium absorption, builds muscle protein, and produces hormones, enzymes, and antibodies. Read more to learn about the health benefits of lysine and how to increase its intake.

Health Benefits Of Lysine

1) Helps Treat Herpes

Herpes simplex-1 (HSV-1) causes herpes (cold sores), the fluid-filled blisters on and around your lips. It is very common among the general population, and you get it from coming into contact with infected saliva [1].

Arginine, an amino acid produced by the body, promotes HSV-1 replication. Lysine and arginine are antagonistic amino acids, which means when lysine is high, arginine is lowered. Hence, lysine will help suppress HSV-1 growth [1].

In a study of 30 participants, a cream with L-lysine, zinc, and herbs cleared herpes symptoms in 40% of the participants by the third day and 87% by the sixth day. When herpes is not treated with lysine, outbreaks may last for 21 days [2].

You can consume more fruits and vegetables to increase lysine and less chocolate, nuts, and gelatin, which are rich in arginine. Supplements can further increase lysine levels in the body and relieve symptoms faster.

People with herpes should couple medications and supplements consumption with a positive change in behavior and habits. Stress activates viruses that are latent or asymptomatic in the body [1].

2) Helps Form Collagen

Collagen is the most abundant protein in our bodies. It builds cartilage, bones, and connective tissues. Lysine helps in the formation and, at the same time, prevents breakdown excretion of collagen [3].

Calcium-collagen is the dynamic duo that prevents bone loss. When you lack lysine, the formation of calcium and collagen is slowed down. This can lead to weak bones and is one of the leading reason why people suffering from lysine deficiency have fragile bones [45].

3) Reduces Anxiety

Lysine can also block serotonin (the ‘happy’ hormone) receptors (specifically 5-HT4) and partially prevent anxiety responses, such as diarrhea [678].

This finding is especially crucial in developing countries, where the diets are grain-based and lysine deficient. People from these regions should aim to eat more food high in lysine, as well as vitamin B, magnesium, and omega-3 fatty acids to reduce stress-induced anxiety and diarrhea [9].

Also, in schizophrenia, severe anxiety-like symptoms can be reduced by supplementing lysine in addition to conventional therapy, although the safety of higher dosage and long treatment periods is yet to be studied [10].

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4) Reduces Diabetes Complications

In diabetic patients, the high blood sugar can damage proteins or lipids by attaching glucose molecules (glycation) and producing advanced glycation endproducts or AGEs. AGEs can cause complications such as damage to the eyes and nerve cells [11].

Lysine prevented the glycation (addition of glucose) of blood proteins in extracted blood from 50 patients with type 2 diabetes [12].

In a cell-based study, lysine prevented the glycation of fibrinogen improving its function [13].

5) Increases Insulin Secretion and Lowers Blood Glucose

Lysine can also act on insulin and glucagon. In one study, lysine decreased fasting blood glucose level and increased insulin and glucagon concentrations in thirteen healthy subjects [14].

Lysine may increase first-phase insulin secretion (of the first signs of type 2 diabetes), as the intake of lysine-glucose mixture led to more insulin than the intake of glucose alone [14].

6) Reduces Pancreas Inflammation

In an animal study, pre- and post-treatment L-lysine reduced pancreas injuries by suppressing inflammation and increasing antioxidant activity. However, it is more effective as a prevention method than therapeutic agent [15].

7) Improves The Function Of The Heart

Low-density cholesterol (LDL) builds up in the walls of the arteries, hardening and narrowing them, which is called atherosclerosis. Blood flow to the heart muscle is either slowed down or blocked, increasing the risk of heart attack.

Lysine produces bodily carnitine, which helps utilize fatty acids and LDL cholesterol [16].

When taken in combination with vitamin C, lysine can help reduce levels of lipoprotein-a (LPA). LPA carries LDL in the blood. The higher the LPA level, the more plagues are built up, clogging the arteries, putting you at risk for heart disease, stroke, and erectile dysfunction [17].

8) Increases Bone Strength

In one study, 15 healthy and 15 osteoporotic women were subjected to acute calcium load, and half of them received lysine supplements. Another group of 45 osteoporotic patients was subjected to either lysine, valine, or tryptophan [18].

Compared to the groups without lysine supplementation, the lysine group absorbed more and excreted less calcium through urine [18].

Therefore, lysine can be used in the prevention and treatment of osteoporosis [18].

9) Promotes Children’s Growth

Growth hormone is stimulated by both lysine and arginine. Nutritional lack of lysine in children can stunt physical and intellectual growth. As such, it is paramount to give children enough lysine for their growth, either through foods or supplements [1920].

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Interactions and Side Effects of Too Much Lysine

Supplements come with various side effects and affect everyone differently. We created SelfDecode to give people answers on a genetic level, so you can know what works best based exactly on your DNA.

1) May Increase Blood Clots during Pregnancy and Breastfeeding

Some data shows that lysine, in combination with vitamins and iron supplementation, can increase hemoglobin levels in pregnant women, as compared to control [19].

More hemoglobin leads to excessive amounts of red blood cells. Blood thickens and can form clots in the bloodstream. Women who are pregnant or breastfeeding are therefore advised to consult doctors before taking the supplement.

2) With Calcium

Lysine increases calcium assimilation, so you need to be cautious when taking large amounts of calcium simultaneously. Hypercalcemia, or excessive calcium, can have adverse effects such as excessive thirst, urination, pain, nausea, and constipation [21].

Hypercalcemia increases risks of heart diseases, such as atherosclerosis (narrowing of arteries), hypertension (high blood pressure) [22].

3) With Arginine

As lysine and arginine are antagonistic molecules that compete for the same transporter molecules, taking lysine and arginine supplement together can cancel their benefits [23].

While high doses of lysine can lower arginine levels in the body to relieve herpes outbreaks, arginine is still an important amino acid that should remain above a certain level. If you take excessive lysine, it may deplete arginine levels [23].

4) Gallstones

Taking too much lysine could increase cholesterol levels and cause gallstones [24].

5) Liver And Kidney Functions

Excess of lysine can be excreted in the urine. Kidney problems can interfere with this ability and cause lysine to accumulate in the blood. In one extreme case, a 44-year-old woman developed Fanconi syndrome and tubulointerstitial nephritis after taking excessive lysine over a five-year period [25].

Consult your physician before using lysine if you have a history of high cholesterol, gallstones, and kidney or liver disease [26].

6) Aminoglycoside Antibiotics

An animal study looked into lysine’s mechanism. Both lysine and aminoglycoside antibiotics bind to what’s called the brush-border membrane vesicles. When fewer drug molecules can bind to these vesicles, they cannot be transported through the intestine for absorption and digestion. They become less effective and more toxic [2728].

Drugs in this group include gentamicin, neomycin, streptomycin, amikacin, tobramycin, kanamycin, and netilmicin [27].

7) Gastrointestinal Problems

Patients with severe herpes outbreaks may be advised to take lysine in high doses (> 9 grams) but they should take note of gastrointestinal upsets, including but not limited to stomach cramps and diarrhea [26].

If you are taking gastrointestinal medications such as prucalopride or tegaserod, you should exercise extra caution. These drugs bind to and activate 5-HT4 receptors. On the other hand, Lysine binds to 5-HT4 to block responses and render such drugs ineffective.

8) Contraindicated in Hyperlysinemia and Hyperlysinuria

People with hyperlysinemia have abnormal levels of lysine in their blood while hyperlysinuria is excessive lysine in the urine. The genetic causes of hyperlysinuria are still unknown [29].

Supplementing with Lysine

Symptoms Of Lysine Deficiency

  • Loss of appetite
  • Excessive hair loss
  • Hyper-stimulated, lack of focus
  • Fatigue
  • Agitation, mood swing
  • Bloodshot eyes
  • Kidney stones
  • Anemia
  • Stunted growth
  • Nausea, dizziness
  • Reproductive disorders

Requirements and Dosages of Lysine

Babies (3 – 4 months old): 103 mg/kg per a day

Toddlers (2 years old): 64 mg/kg per a day

School-aged children: 58 mg/kg per a day [30]

Adults: 30 – 35 mg/kg per a day [3132]

Lysine intake in a typical Western diet is 40 – 180 mg/kg per a day, with the upper limit being 300 – 400 mg/kg per a day [31].

Typically, the recommended intake of lysine is only 1,000 mg per day. However, the daily dose of up to 3 grams is safe for therapeutic purposes when taken in three separate doses [133].

Some patients may require chronic use at higher doses. For example, herpes patients could take up to 9 grams per day during an outbreak [34].

Lysine tastes somewhat unpleasant (salty), and consumers are suggested to add some amino acid flavoring into the mix for better taste.

Ways to Incorporate More Lysine

1) Eat Lysine-Rich Food

It is crucial to obtain enough lysine through our diet as we cannot produce it in our body. Diets in developing countries contain 70 to 80% grains and, thus, lysine becomes the limiting amino acid [9]. Adding foods that are higher in lysine, such as legumes and animal products, should help with this limitation.

Foods containing lysine include:

  • Lean beef and lamb – 3582 mg/100g
  • Parmesan cheese – 3306 mg/100g
  • Poultry (turkey, chicken) – 3110 mg/100g
  • Pork – 2757 mg/100g
  • Soya beans and products (tofu, protein powder, flour) – 2634 mg/100g
  • Tuna – 2590 mg/100g
  • Shrimp – 2172 mg/100g
  • Pumpkin seeds – 1386 mg/100g
  • Eggs – 912 mg/100g
  • White beans – 668 mg/100g [35]
  • Other fish (cod, sardine) and shellfish
  • Nuts, seeds, eggs, beans, and lentils
  • Spirulina and fenugreek seeds [36]

Unsure which foods are right for you and which aren’t? Check out the Lectin Avoidance Diet. It’s specifically designed to help you find exactly what foods cause you problems so you can start eating worry free.

2) Taking Supplements (Tablets, Capsules, Liquids)

You should be able to obtain sufficient lysine through diets.

Even though lysine supplements are over-the-counter, they should only be taken during herpes breakouts, not on a regular basis. Kidney problems have been reported from long-term use, and high doses can cause abdominal pain and diarrhea.

3) Applying L-lysine Cream

Lysine is also available in ointment form as a treatment for cold sores and skin injuries.

You should not use different formulations of lysine (tablets, liquids, others) simultaneously unless otherwise directed. Doing so may increase the risk of overdosage.

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