Lysine is an essential amino acid. Reported lysine benefits include improved blood sugar control, management of anxiety and stress, collagen formation, and wound healing. Your body cannot make lysine, so you must get it from food or supplements.
There are two chemical versions of lysine: L-lysine and D-lysine. L-lysine is the bioactive form found in foods and supplements that your body uses, and it's our focus here.
In addition to potential lysine benefits and uses, this article discusses lysine supplement doses, side effects, food sources, and more.
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How to Choose a Supplement
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products (such as the U.S. Pharmacopeia, Consumer Labs, or NSF) and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Lysine Benefits
Lysine is an amino acid, and your body uses it to make proteins and repair muscles.
Lysine supplements may provide benefits for the following:
- Cold sores from herpes simplex virus (HSV)
- Anxiety and stress
- Schizophrenia
- Blood sugar control
- Calcium absorption
- Wound healing
The research on many of these benefits is limited. Before starting lysine supplements, please talk with a healthcare provider to ensure they are safe for you.
Cold Sores
Cold sores are an unpleasant side effect of HSV 1.
A 2017 review found that oral lysine supplementation of 3 grams per day or more improved some people's experiences with cold sores. However, the review stated that more research is needed to determine whether lysine is an effective treatment for this condition.
An earlier review conducted in 2015 also did not find enough evidence to support claims that lysine can relieve cold sores.
Stress and Anxiety
Studies have looked at whether lysine can help manage anxiety and stress. Research is limited, and it should be noted that many of the studies are small and don't include many participants.
A study found that cortisol (a hormone that's increased during stress), was lowered in people who consumed lysine-fortified foods for three months. The study also found that these foods reduced anxiety measures in males.
Schizophrenia
Lysine may also be used as a complementary treatment for schizophrenia, according to limited research.
A small study reported that people taking 6 g of lysine daily for four weeks had improved symptoms, including reduced psychosis severity. However, the researchers reported that possible placebo effects could have impacted the self-reported findings.
A study looked at the use of 6 g of L-lysine with risperidone (a drug used to treat mental conditions), in people with schizophrenia over eight weeks. The study showed that schizophrenia symptoms decreased more for people who took L-lysine. However, the safety and efficacy of higher doses and longer-term use of L-lysine are still uncertain.
Blood Sugar Control
Lysine supplements may be useful for lowering blood sugar.
A very small study found that high doses of lysine (11 g) taken with glucose resulted in small decreases in blood sugar. Researchers think that lysine supplementation may either help with insulin secretion or help remove glucose from the blood on its own.
However, more research is needed. Follow your healthcare provider's guidance for blood sugar control.
Calcium Absorption
Lysine supplements may help the body absorb calcium, which can benefit osteoporosis (a disease that causes weak, brittle bones).
However, many studies have been done in vitro (in a lab or test tube) or on animals. This means that it's difficult to definitively conclude the effect of lysine on treating osteoporosis in humans.
A 2018 study evaluated the bioavailability (absorption into the body) of calcium lysinate compared to other calcium supplements in improving bone mineral density (BMD) in people with osteopenia. The results showed much higher bioavailability of calcium lysinate and improved BMD T-scores, suggesting that calcium lysinate may be a better dietary calcium supplement for people with osteopenia. This study was small, with only 18 participants, so further research is needed.
One study on rats concluded that dietary lysine increased the amount of calcium absorbed by the body. The study also reported that lysine supplementation prevented the rats from experiencing loss of bone matter, as seen in osteoporosis. It's important to note that this study was conducted in rats and did not involve human participants. We cannot say that these effects will even happen in humans.
Before further conclusions are drawn, more high-quality studies using lysine with humans are needed. If you have osteoporosis, follow your doctor's prescribed treatment plan and consult your healthcare provider before taking any supplements.
Wound Healing
Lysine has been shown to enhance blood supply and target growth factors, leading to improved wound healing.
A small study evaluated adding a 15% lysine cream to standard treatment for diabetic foot ulcers.
Researchers concluded that 15% lysine cream can significantly improve wound healing, but they noted that more extensive studies are needed to confirm these findings.
Sources of Lysine
Lysine is an amino acid found in various protein foods, so most people can get all the lysine they need through their diet.
Since lysine is so widely available in food, it is recommended that people take a food-first approach to getting enough of it. Lysine supplements would only be required if recommended by a healthcare professional due to an underlying health issue.
Some people, like those who follow a vegan diet, may have difficulty getting enough lysine.
Food
The best sources of lysine come from animal foods, but it can also be found in some plant-based proteins.
The best way to ensure you're getting enough lysine in your diet is to eat a variety of protein foods, including both animal and plant sources. The recommended daily intake for lysine is 35 milligrams per kilogram (kg) of body weight.
Non-vegan food sources of lysine include:
- Meat
- Chicken
- Dairy products
- Eggs
- Fish
- Shrimp
- Shellfish
Vegan food sources of lysine include:
- Beans
- Wheat germ
- Lentils
- Nuts
- Seeds
- Soy
- Spirulina
Supplements
Lysine supplements are available in various forms, including:
- Capsules
- Chewable
- Powders
The right form of supplement for you will depend on personal preferences.
Many lysine supplements are also vegan or gluten-free. The label should tell you whether the supplement is either vegan or gluten-free. The label should also list the supplement form.
Topical lysine (cream) is also available, but only in combination form. This means lysine creams may include other ingredients, like vitamins, minerals, or nutrients.
Lysine Dosage
There is no standard recommended dose for lysine supplements. The amount of lysine required depends on your body weight. Fortunately, most people can get enough lysine through their diet.
Various studies on lysine for cold sores have used a wide range of doses from 300 milligrams per day to 3 grams per day. Other studies evaluating lysine supplements have used even higher amounts.
The tolerable upper limit of intake for lysine is estimated to be 7.5 grams per day.
Because there is no standardized dose for lysine, it's best to talk with your healthcare provider before starting lysine supplements. They may be able to determine the best dosage for you and answer any lingering questions.
What Happens if You Take Too Much Lysine?
Lysine is considered to be a safe, non-toxic supplement to take.
There is no upper limit, or maximum dose because the side effects of taking larger amounts are not severe. Some researchers suggest taking no more than 6 grams of lysine per day.
Experiencing any common side effects after taking oral lysine may indicate that you've taken too much. Follow your healthcare provider's advice on how much lysine you should take.
Side Effects
While lysine supplements are generally considered safe for most people, side effects are possible.
Common Side Effects
Common side effects of lysine supplements include:
- Stomach pain
- Diarrhea
- Nausea
Typically, these gastrointestinal side effects don't last for long and can be treated at home. They usually only occur with larger doses of lysine.
However, if you experience long-term side effects from taking oral lysine, visit your healthcare provider.
Severe Side Effects
Severe side effects are rare but possible, like kidney failure.
Kidney failure has been reported from taking too much lysine. One case report on a 44-year-old woman found that high doses of lysine caused Fanconi Syndrome, a severe disorder involving the kidneys. Her symptoms eventually led to kidney failure.
As this case report was just one person, the evidence of kidney failure associated with taking lysine is limited. Additional research available on this topic has mostly been performed on animal models.
Interactions
Possible food, drug, or supplement interactions with lysine include the following:
- Arginine (another amino acid): Taking a large dose of arginine with lysine may cause lower levels of lysine absorption. This is because some receptors in your body prefer arginine over lysine.
- Calcium: Lysine may increase the amount of calcium your body absorbs. If calcium and lysine are taken in large amounts, they may potentially lead to hypercalcemia (too much calcium in your body).
It is essential to carefully read a supplement's ingredient list and nutrition facts panel to determine which ingredients and how much of each are included.
Who Shouldn't Take Lysine Supplements
Certain people should avoid taking lysine supplements, including:
- People who are pregnant or breastfeeding: There is not enough evidence to know if lysine is safe for these populations.
- People who take large amounts of calcium supplements: Lysine may increase the amount of calcium your body absorbs. If calcium and lysine are taken in large amounts, they may potentially lead to hypercalcemia (too much calcium in your body).
- Anyone with lysinuric protein intolerance: This is a rare condition in which the body cannot properly digest lysine and other amino acids.
Before starting any new supplements, it's important to talk to your healthcare provider first.
Summary
Lysine is an essential amino acid that can be found in high-protein foods like meat, nuts, beans, and eggs. It is also available as an oral supplement for those who need it. However, taking a food-first approach to getting enough of it is usually recommended.
Some research suggests that lysine may be helpful for treating certain conditions, like cold sores and anxiety. More research is needed to determine the full extent of lysine's safety and efficacy when used for these conditions. Before taking lysine, talk to your healthcare provider about dosage and how to best use the supplement.
