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  • Denise Fixsen & Brindley Brooks

L-Lysine: An HS Fad Revisited

Medically Reviewed by Jillian Ondreyka, MPH, RDN, IFNCP, IBCLC, CLT

L-Lysine is not a new fad in HS; it was introduced between 2015 and 2016 and has resurfaced recently.

Some important questions to ask yourself before you start taking this, or any

supplements, include:

  • What is L-Lysine?

  • What is its function in the body?

  • How will this impact my HS?

  • Are there any contraindications to taking this supplement?

  • Could it have any negative consequences or interact with any medications I’m currently taking?

  • Do I need it?

We are all looking for the “magic cure” or a "miracle" for HS and are desperate for anything that will help us all live a less painful life, but the fads that come along claiming to be the next cure can be dangerous. We are not dissuading people from trying new potential therapies for their HS, we are asking you to do this safely, under the supervision of your medical provider and to be aware of the potential risks of any therapy, especially those with no existing research.

There is no such thing as a benign reaction (no reaction) to a pharmaceutical, supplement or natural product. Everything that you take should be researched and tailored to your personal situation. Always talk with your physician and/or someone trained in the use of natural/herbal/health supplements prior to changing your current regime (the sales person at the supplement store does not fit this criteria).

It is important to take any other illnesses, diseases or health conditions into account when adding a supplement as you do not know what impact this supplement may have on your overall health or other conditions.

What is Lysine?

Lysine is an essential amino acid in humans, which cannot be synthesized by the body through regular metabolic processes. Therefore, it has to be included in the diet. Generally, meat, fish, dairy, and eggs contain lysine. Also, some plants such as soy and other legumes contain lysine. (Reference 1, 2)

What is L-Lysine?

L-lysine is the biologically active form of lysine. Therefore, all food contains L-lysine.Lysine, or L-lysine, is an essential amino acid, meaning it is necessary for human health, but the body cannot make it. You have to get lysine from food or supplements. Amino acids like lysine are the building blocks of protein. Lysine is important for proper growth, and it plays an essential role in the production of carnitine, a nutrient responsible for converting fatty acids into energy and helping lower cholesterol. Lysine appears to help the body absorb calcium, and it plays an important role in the formation of collagen, a substance important for bones and connective tissues including skin, tendons, and cartilage. (Reference 1, 2)

What is Lysin?

You may see research shared for Lysin when talking about Lysine or L-Lysine. Please note this is NOT the same thing as Lysine or L-Lysine. Lysin is an enzyme and is not the same as Lysine or L-Lysine. This research is not applicable to what is being discussed with this amino acid.

What is an amino acid?

Amino acids are molecules used by all living things to make proteins. The human body uses just 20 amino acids to make all the proteins it needs to function and grow. Because amino acids can be arranged in many different combinations, it's possible for your body to make thousands of different kinds of proteins from just the same 20 amino acids.

There are both essential and non-essential amino acids. Lysine is one of the 9 essential amino acids. It is important to get enough of all of the essential amino acids so that they are balanced throughout the day. You don't want to take a lot of one amino acid and neglect to take any of the other amino acids. To promote amino acid intake, eat a variety of protein foods such as beef, chicken, eggs and fish.

The non-essential, also known as dispensable amino acids, can be excluded from a diet.

The human body can synthesize these amino acids using only the essential amino acids. (Sources 3, 4)

The 20 to 22 amino acids that comprise proteins including:




Aspartic Acid


Glutamic acid















Selenocysteine and Pyrrolysine (can be incorporated by special translation mechanisms)

Of these 20 standard genetic code amino acids, nine amino acids are essential:










Who Should Avoid Taking L-Lysine?

Those who should be cautious taking L-Lysine include:

  • If you have osteoporosis

  • Lysinuric protein intolerance

  • Kidney disease

  • Pregnant / Breastfeeding

L-Lysine can increase how much calcium your body absorbs; avoid taking large amounts of calcium when taking L-Lysine.

It is possibly safe for someone to take up to a year; Fanconi syndrome and tubulointerstitial nephritis are associated with lysine supplementation taken over a 5-year period.

Other drugs may interact with L-Lysine, including prescription and over-the-counter medications.

Side effects of L-Lysine include:

  • diarrhea

  • abdominal pain

  • chronic kidney (renal) failure

  • inflammation in the kidney (interstitial nephritis)

  • increased calcium absorption

  • excessive doses can cause gallstones

HS and IBS tend to go hand in hand. Please be very cautious prior to starting a supplement such as this without the advice of your physician.

Where Does L-Lysine Come From?

It’s important to try to get nutrients from food first before using supplements. How nutrition promotes good health is complex, and most often eating the food source of a nutrient is more effective than taking a supplement. The nutrients in different foods work synergistically in that each one can increase the health effects of the other. For example, eating an iron-rich food together with a vitamin C-rich food increases your body’s absorption of iron.

It is best to eat a variety of foods each day to insure intake of different nutrients, vitamins, and minerals. If foods alone do not meet your nutrient needs, then you may need to take a supplement. Most people get enough lysine in their diet. Although athletes, burn patients, and vegans who do not eat beans may need more. If you do not have enough lysine, you may experience (Reference 2):

  • Fatigue

  • Nausea

  • Dizziness

  • Loss of appetite

  • Agitation

  • Bloodshot eyes

  • Slow growth

  • Anemia

  • Reproductive disorders

What Is L-Lysine Used For?

Lysine has been used in alternative medicine as a possibly effective aid in treating cold sores due to herpes simplex.

Other uses not proven with research have included canker sores, diabetes, stress, and for athletic performance improvement.

How Much Should Someone Take?

Do you know how many mg you should be taking? Only you and your physician and/or trained professional can assess your personal needs.

For herpes 500mg 2-3 times daily for a total of 1,500 mg is suggested. Use L-Lysine exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. (Source 5)

Could L-Lysine Be an HS Trigger?

Yes, it's possible. Lysine can be found in foods such as legumes, cheese, yogurt, meat, milk, brewer's yeast, wheat germ, and other animal proteins, so if these are a personal trigger for you then it's possible L-Lysine could be as well.

If you are sensitive to an ingredient and you take a concentrated supplement of the ingredient, you might have a reaction. For example, if you are sensitive to broccoli and it causes you to have a flare and you take a supplement of concentrated broccoli, then you could have a flare.

Fillers / Other Ingredients in Supplements

What you don’t know, based on a label, is what is contained in the OTHER INGREDIENTS listed. These are known as fillers. Is something in one of those general fillers a trigger for you? We don’t have the benefit of knowing the inside information on what specifically is in those other ingredients because supplements are not FDA approved, so they are not required to divulge that information. This is true for all supplements, not just L-Lysine.

It is not certain whether lysine is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Lysine should not be used in place of medication prescribed for you by your doctor.

Lysine is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination. Look for “professional grade” supplements as these are tested by independent third parties for quality. (Reference 5)

Please use caution and ask pertinent questions when you see things like this in groups, etc. If it sounds too good to be true, it most likely is. We are all desperate for something to work for this debilitating condition, but constantly overloading your body with different vitamins, supplements, minerals, or medication is not the answer; there is the potential to create additional problems without being aware of the impact it's having on your body.



"The researchers found that when they removed individual essential amino acids from a diet, the subjects would be unable to grow or stay in nitrogen balance.

In general, the optimal ratio of essential amino acids and nonessential amino acids requires a balance dependent on physiological needs that differs between individuals.

Finding the optimal ratio of amino acids in total parenteral nutrition for liver or kidney disease is a good example of different physiological states requiring different nutrient intakes. Therefore, the terms "essential amino acid" and "nonessential amino acids" may be misleading since all amino acids may be necessary to ensure optimal health.”

Related Articles:

Content in this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking treatment because of something you have read on this website.

Written by Denise Fixsen and Brindley Brooks

Medically Reviewed by Jillian Ondreyka, MPH, RDN, IFNCP, IBCLC, CLT

Edited by Brindley Brooks


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