Lysine is an amino acid. Amino acids are molecules that act as the building blocks of proteins.
Specifically, lysine is an essential amino acid. That means that your body can’t make lysine on its own, and instead it must be obtained through your diet.
Lysine can be found in protein-rich plant and animal-based foods like eggs, lentils, meat, dairy products, and fish.
Lysine can also be taken as a dietary supplement. The supplement label might say “l-lysine,” which is the form of lysine used in supplements. As a supplement, lysine offers a number of benefits.
Benefits of Lysine
Lysine is required for important processes such as:
- Tissue repair
- Collagen formation
- Calcium absorption
- Antibody, hormone, and enzyme production
Most people get plenty of lysine through their diets. Some people—like athletes, those who are being treated for extensive burns, and those following a vegan diet—may not take in enough lysine through their diet alone to meet their needs. Supplementation of lysine might help make up for that.
Plus, some studies suggest that taking lysine in supplement form may benefit certain medical conditions.
May Prevent Herpes Flares
Lysine supplements may benefit people who have recurrent infections caused by the herpes simplex virus (HSV).
To replicate, HSV needs the amino acid arginine. Lysine blocks HSV from using arginine, which prevents the virus from reproducing. For this reason, taking high doses of supplemental lysine could help reduce the recurrence of HSV lesions like cold sores and genital sores.
One review found that when supplemented in doses higher than 3 grams per day, lysine may help reduce the number of herpes flares and self-reported herpes symptoms in people with herpes.
However, more research is needed to understand how lysine supplements affect people with herpes and to determine what minimum daily dose is needed to produce positive effects.
Might Reduce Anxiety
When combined with the amino acid arginine, lysine may help improve anxiety symptoms.
This may be because the body requires amino acids like lysine and arginine for the production of neurotransmitters—chemical messengers that allow nerve cells to communicate. Low amino acid intake could lead to an imbalance in neurotransmitters, which could lead to anxiety.
An older study of 108 Japanese adults found that those who took a supplement containing 2.6 grams of lysine and 2.6 grams of arginine for one week experienced significant reductions in anxiety. They also had significant reductions in salivary cortisol, a marker used to assess levels of psychological stress.
Other older studies have had similar outcomes.
Even though these results are encouraging, more studies are needed to investigate the effects of lysine supplementation on anxiety.
May Prevent Mouth Sores
Lysine is important to collagen formation. Collagen may be able to help heal mucosal wounds, which are wounds like sores that affect the moist lining of the inside of your mouth. Taking lysine supplements can help promote collagen production, in turn, decreasing and preventing sores and inflammation (mucositis) from things like radiation or chemotherapy.
May Help Lower Blood Pressure
If your diet is low in lysine, taking a lysine supplement may help reduce blood pressure. In a study conducted in Ghana, people with high blood pressure and suboptimal lysine intake who were supplemented with 500mg of lysine per twice daily for 16 weeks experienced significant reductions in systolic blood pressure compared to a group that took placebo tablets.
Systolic blood pressure is the top number of your blood pressure reading and measures the pressure in your arteries when your heart beats. High blood pressure can increase your risk of heart disease, heart attack, and stroke.
More research is needed to know the true effect a lysine supplement can have on high blood pressure,
Might Improve Symptoms of Schizophrenia
Schizophrenia is a mental health disorder that can cause people to hear voices or see things that aren’t there.
One study showed that when used alongside the schizophrenia medication risperidone, daily supplementation with 6g of lysine (two 1-gram capsules three times a day) for eight weeks led to improvements in schizophrenia symptoms.
More research that uses higher doses and a longer time period are needed.
May Increase Muscle Strength
Some evidence suggests that lysine-rich diets protect against protein breakdown and improve muscle strength. Twenty under- and well-nourished men who ate a high-lysine diet (80mg per kg of body weight per day) for eight weeks had a slight positive effect on muscle strength.
Therefore, supplementing your diet with lysine may benefit muscle heath.
Good Sources of Lysine
Lysine is concentrated in a number of plant- and animal-based foods, including:
- Red meat
- Cheeses, like parmesan
- Brewer’s yeast
- Soy products like soybeans and tofu
- Fenugreek seed
How to Take Lysine
Most people get enough lysine through their diet. However, taking lysine supplements could be helpful for people who don’t eat a lot of lysine-rich foods like meat, fish, eggs, dairy products, and beans or for those who are trying to manage a specific condition.
Lysine supplements are most commonly available as capsules and powders. You can take lysine on its own or you can take it alongside other amino acids, like arginine.
Most supplement companies suggest taking lysine on an empty stomach for optimal absorption. However, most studies that have investigated the health effects of lysine supplements didn’t disclose whether participants were instructed to take lysine with meals or on an empty stomach.
Most lysine supplements come in tablets that have between 500mg and 1,000mg of lysine per dose. How much you take and for how long depends on body weight and what condition you’re hoping to help.
Usually, lysine supplements are used in doses up to 3,000mg a day for up to one year.
Lysine has been determined to be likely safe in doses up to 3,000mg a day for up to one year and up to 6,000mg a day for up to eight weeks. In fact, 6,000mg a day was the highest dose of lysine not associated with adverse side effects like diarrhea and nausea, according to one review that included 71 studies.
Higher doses may be safe, but they may cause side effects like diarrhea and nausea in some people.
Some people may require higher or lower doses of lysine than others, so it’s important to reach out to a healthcare provider if you have questions regarding lysine dosing.
Is Lysine Safe?
Like most amino acids, lysine supplements are considered relatively safe, even at higher doses.
However, people with medical conditions such as heart disease, kidney disease, liver disease, gallstones, or asthma, as well as those who are pregnant or breastfeeding, should avoid taking lysine supplements unless a healthcare provider prescribes them.
People with lysinuric protein intolerance should also avoid taking lysine supplements. This intolerance is a rare genetic condition where the body is unable to digest and use certain amino acids such as lysine. Because people with this condition have a hard time absorbing lysine, taking lysine supplements may cause gastrointestinal side effects such as diarrhea and stomach cramps.
Complications from lysine are rare. There has been one published case report from more than nearly 30 years ago in which experts believed that a lysine supplement caused a woman to develop Fanconi's syndrome, a condition that affects the kidneys and leads to decreased absorption of electrolytes and other important substances. After taking 3000mg of lysine for five years, the woman eventually went into kidney failure.
Potential Drug Interactions
Lysine isn’t known to interact with any medications.
However, if you’re currently taking one or more medications, you shouldn’t start taking lysine supplements without clearing it with your healthcare provider first.
There’s always a chance that a dietary supplement could interact with a medication or another dietary supplement, especially supplements containing more than one ingredient.
What to Look For
Lysine supplements are available for purchase online and in health food stores. The label might say “l-lysine.”
When shopping for a lysine supplement, it’s important to purchase supplements from trusted brands that adhere to strict quality and safety standards.
Many brands use third-party labs to test their products for quality and purity. Whenever possible, choose supplements that are certified by third-party organizations like UL, USP, and NSF International.
You’ll also want to consider supplement form, cost, and additives.
If you can’t tolerate swallowing pills, a powdered lysine supplement might be a better choice.
When scanning supplement labels, keep an eye out for ingredients that you may prefer to leave out of your diet, like added sugars, fillers, and artificial colors and flavors. These additives are commonly used in dietary supplements like gummies and powders.
Can You Take Too Much Lysine?
Even though lysine is considered safe at higher doses, you should avoid taking more than 6,000mg per day. Doses higher than that may cause side effects like stomach cramps, nausea, and diarrhea.
If you’re unsure how much lysine you should be taking per day, ask your healthcare provider for advice. They can determine whether lysine supplementation is appropriate for your specific needs and can recommend a safe and effective dose.
Side Effects of Lysine
Lysine isn’t linked with many adverse side effects. However, taking doses higher than 6,000mg per day may cause digestive symptoms such as:
- Stomach cramps
If you experience side effects after taking a lysine supplement, stop taking the supplement and contact your healthcare provider for advice.
A Quick Review
Lysine is an essential amino acid that’s involved in growth, tissue repair, collagen production, and other important bodily functions.
It’s concentrated in foods like meat, fish, eggs, and beans and can also be taken as a dietary supplement. While most people get plenty of lysine through their diets and don’t require supplemental lysine, supplementation can be helpful for people who don’t get enough lysine in their diets. Plus, some evidence suggests that supplemental lysine may be helpful for certain people, like those with recurrent herpes outbreaks or anxiety.
If you’re interested in taking lysine supplements, be sure to clear it with your healthcare provider first. This is especially important if you have a medical condition like gallstones or kidney disease or if you’re taking one or more medications.
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