Lysine Supplements Review
Choose the Best Lysine
Supplement. CL Tests Reveal Which Lysine Supplements Provide the Best Quality
and Value.
Medically reviewed and
edited by Tod Cooperman, M.D. 
Last Updated
: 04/07/2020 | Initially Posted:
02/06/2016
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Table of Contents
Summary
·
What is lysine? Lysine (L-lysine) is an essential amino
acid found in many protein-rich foods (see Lysine in Food) and is needed for proper
growth and other critical functions (see details in What It Is).
·
What are the health benefits of lysine? As a supplement,
lysine may help prevent cold sores (herpes simplex labialis), genital herpes
lesions, and canker sores. Although it is also found in topical products for
cold sores, it is not known to be active topically (See details in What It Does).
·
COVID-19 UPDATE: Due to its potential antiviral and immune-stimulating
properties, lysine is being promoted fight coronavirus (SARS-CoV-2) infection
(COVID-19). However, there is no evidence at this time to suggest taking lysine
supplements can help prevent or treat COVID-19. See the COVID-19 section
section for details.
·
How much lysine to take? Typical daily dosage is 1,000 to 3,000
mg (see details in Quality Concerns).
·
Lysine has also been used to prevent/treat feline herpesvirus 1
infection — but there is no clinical evidence to support this use and it is not
recommended (see details in What It Does, For Cats).
·
What did CL's tests of lysine find? CL's tests found
that all but one product contained their listed amounts of lysine (see details
in What CL Found).
·
Best value for lysine: The cost to obtain lysine from CL
Approved products ranged from 4 cents to 33 cents per 1,000 mg (and up to 72
cents for cat products). See which CL Approved products provide the best value.
·
To compare product test ratings, ingredients, and prices, see
the Results Table.
·
Lysine safety and side effects: People with kidney
disease, gallstones, elevated cholesterol, and glutaric acidemia type I should
exercise caution with lysine supplements (see details in Concerns and Cautions).
What It Is:
Lysine
is an essential amino acid, meaning that it must be obtained from foods,
because the body is unable to make it. It is important for proper growth, and
is involved in the production of collagen as well as calcium absorption. Most
people need about 1 gram per day, which can typically be provided by a 100 gram
(3.5 oz) serving of protein rich food such as beef or poultry, eggs or cheese.
Vegetarian sources include tofu, beans, nuts such as peanuts and almonds, and
sunflower seeds. (See Lysine in Foods table below for amounts
found in individual foods.)
What It Does:
Herpes simplex virus (cold sores and genital herpes)
Some, but not all studies, suggest that taking between one to three grams of
lysine from supplements daily may help to reduce the occurrence and
severity of cold sores (herpes simplex labialis). Lower doses may not
be effective.
A small double-blind, placebo-controlled study in men and women with recurrent
cold sores or genital herpes lesions found those who took
tablets providing one gram of L-lysine monohydrochloride three times daily (a
total daily dose of 3 grams) for six months had an average of 2.4 fewer cold
sore or genital lesion outbreaks, as well as a significant reduction in symptom
severity and healing time, compared to placebo (Griffith, Dermatologica 1987).
Another small study reported that taking a little over one gram of L-lysine
monohydrochloride daily reduced the recurrence rate of cold sores, although it
did not shorten healing time compared to placebo (McCune, Cutis 1984). The study also reported
that a lower dose (a little over half a gram per day) did not have an effect.
However, another double-blind study found no reduction in the recurrence of
cold sores or rate of healing compared to placebo during three months of daily
supplementation with 1 gram of L-lysine-monohydrochloride (Milman, Acta Derm Venereol 1980).
A small cross-over study among people with recurring cold sores had mixed
results: it found that those who took 1 gram of L-lysine monohydrochloride
daily for six months did not have significantly fewer cold sores compared to
placebo; however, during the next six months when participants switched and
took the treatment they did not take during the first six months (either lysine
or placebo), those who took lysine did have significantly fewer cold sores (1.8
versus 2.9) compared to placebo (Thein, Oral Surg Oral Med Oral Pathol
1984). The study also reported that the number of cold sores was
associated with blood levels of lysine, with occurrences reduced in those with
blood levels of lysine above 165 nmol/ml.
There are no studies on the effect of lysine in treating an existing herpes
eruption.
Laboratory research suggests that lysine may help to inhibit the herpes simplex
virus by blocking arginine, an amino acid needed by the virus to replicate;
therefore, it has been theorized (but not proven) that limiting intake
of foods high in arginine (such as chocolate, peanuts, other nuts and seeds)
may be helpful if trying to prevent a herpes eruption (Griffith, Chemotherapy 1981). However, there
is no evidence that eating these foods triggers a herpes eruption.
Canker sores
One study reported that 400 mg of lysine daily may help to prevent canker
sores, while a dose of 4 grams daily may decrease healing time for canker
sores (aphthous ulceration) (Wright, Gen Dent 1994). [Note: There had been
speculation that canker sores are caused by infectious agents such as Helicobacter
pylori and herpes simplex virus, but investigations suggest that this
is not correct. Other causes have been proposed, such as stress, physical or
chemical trauma, and food sensitivity (McBride, Am Fam Phys 2000).] A small
placebo-controlled study among people with recurring canker sores found that
62.5% of those who took 2 tablets of lysine daily with meals (Herpetrol, Alva-Amco
Pharmacal Cos., Inc.) providing a daily total of 630 mg of L-lysine
monohydrochloride reported a decrease in the recurrence of canker sores, while
just 14% of the placebo group experienced a decrease (Ozden, J Exp Integr Med 2001). However, among those taking
lysine who did develop a canker sore, symptoms (itching, burning, and redness)
and duration were not improved. Herpetrol no
longer appears to be available as a dietary supplement; it is now sold as a
topical gel with other ingredients.
Immune system health, flu, and COVID-19
Studies in mice have suggested that lysine may stimulate the immune system and
increase levels of T-lymphocytes, cells that help to fight infection (Niijima, Brain Res Bull 1998), as well as
increase blood levels of zinc (which is also important for a healthy immune
system) (Giroux, J Med Bord 1977). In people, small
studies in China and Pakistan also found that lysine-fortified flour increased levels
of a particular T cell (CD3 T) and certain immunoglobins (IgG, IgA, and IgM) (Zhao, Food Nutr Bull 2004; Hussain, Food Nutr Bull 2004).
However, a small study among nursing home residents in Indonesia found that
taking 500 mg of lysine, in addition to 20 mg of zinc (as zinc sulfate), daily
for two months did not decrease the incidence of flu compared to zinc alone nor
compared to a control group that received no supplementation (Widijanti, Biochem Physiol 2015).
Due to its potential immune
system and antiviral benefits, supplementation with lysine has been promoted by
some websites to help prevent or reduce the symptoms of COVID-19, the infection caused by the SARS-CoV-2 virus.
However, there is currently no evidence to support this use. One study being
touted as evidence that lysine may help reduce COVID-19 infections involves an
inhaled medicine (D, L-lysine-acetylsalicylate glycine, also called LASAG),
which is essentially aspirin combined with lysine and glycine
to improve its solubility and stability. This study showed that the medication
(which is also used in some countries to treat migraine) reduced the duration
of symptoms in people hospitalized with severe influenza who were also taking
Tamiflu (Scheuch, Emerg Microbes Infect 2018). This compound
has also been shown to inhibit other coronaviruses (SARS-Cov
and MERS-CoV) in-vitro (Muller, J Antivir
Antiretrovir 2016). There is no evidence
at this time to suggest that supplementing with lysine would have these
effects.
Calcium absorption
Lysine supplementation may increase calcium absorption, as demonstrated in
short-term studies of women with osteoporosis given 400 mg and 800 mg of
L-lysine (Civitelli, Nutrition
1992).
Topical lysine
Lysine is available in several topical products (gels
and creams) for cold sore relief, typically in combination with other
ingredients. Although "lysine" is often in the name of these
products, it is actually not an "active" ingredient and there is no
good clinical evidence that these topical products are effective.
For example, topical gels such as Herpetrol
and Lysimax (both by Alva-Amco Pharmacal Co., Inc.) include benzalkonium chloride (an
antiseptic), menthol (an analgesic), and only list an unspecified amount of
lysine HCL as an "inactive ingredient." Similarly, a
cream, SuperLysine Plus+ from
Quantum Health Inc., lists menthol as the active ingredient, and only includes
lysine as an inactive ingredient, along with a many other ingredients, such as
beeswax. A study funded by the maker of this product found that among people
with a recent eruption of a cold sore who applied the cream every two hours,
40% reported full resolution of the sore by the third day and 87% by the end of
the sixth day (Singh, Altern Med Rev 2005).
However, this study did not include a placebo, making the results of
questionable value.
For cats
Feline herpesvirus 1 is a highly contagious virus that affects many cats,
causing flu-like signs and irritation of the eye and nose. Lysine
supplementation has been popularly used to prevent and treat these infections.
However, a comprehensive review of evidence in 2015 concluded that there is a
"complete lack of any scientific evidence for its efficacy" and
recommended against its use (Bol, BMC Veterinary Research 2015).
Quality Concerns and
Tests Performed:
Neither
the FDA nor any other federal or state agency routinely tests lysine
supplements for quality prior to sale. ConsumerLab.com, as part of its mission
to independently evaluate products that affect health, wellness, and nutrition,
purchased several dietary supplements sold in the U.S. claiming to contain
lysine. These were tested for their amount of lysine. Standard tablets and
caplets were also tested for their ability to properly disintegrate
("break apart") as needed for absorption.
What CL Found:
All but one of the 12 lysine products selected for testing by
ConsumerLab.com were found to contain their listed amounts of L-lysine, and all
tablets and caplets were able to properly disintegrate in solution. Seven
products tested through CL's voluntary Quality Certification Program passed
the same tests. All products were purchased on the market by ConsumerLab.com.
The one product which was not Approved was Douglas Laboratories
L-Lysine. ConsumerLab.com found the labeling to be misleading and it does
not appear to conform to FDA requirements. While the front of the label
identifies the product as "L-lysine" the Supplement Facts panel on
the back, instead shows the amount of "L-lysine HCl...500 mg".
ConsumerLab.com found that the product contained only 416 mg of free
form l-lysine, which is just 83% of what one might expect.
All of the reviewed products provide L-lysine in the form of L-lysine HCl (also
called L-lysine hydrochloride or monohydrochloride). The HCl portion of the
L-lysine HCl is about 20% of the compound's weight but only acts to stabilize
the l-lysine and is not supposed to be included in the listed weight of
L-lysine on labels. The other products properly list only the weight of
L-lysine, excluding the HCl. This is the format suggested by FDA guidelines (Dietary Supplement Labeling Guide:
Chapter IV, Example 15) which explain, for example, that when
listing calcium carbonate on labels, only the weight of calcium, not carbonate,
is to appear in the Supplement Facts panel.
The images below shows the Douglas Laboratories label compared
to a one of the properly labeled products.
Best Value
As all the products contain only L-lysine as the active ingredient and all are
made with L-lysine HCl, it is fairly easy to compare the products on price.
Some products state "free form" on their labels, but the form is
still L-lysine HCl and this appears to refer only to the fact that the amount
listed in the Supplement Facts panel is that of L-lysine and does not include
the HCl portion. The only significant difference among the products is whether
they are formulated as capsules, tablets/caplets, powders, or, for cats, chews
— and this should not make much difference in terms of absorption. If not made
correctly, tablets and caplets many not properly break apart to release their
ingredients, but ConsumerLab.com's tests of products
in tablet or caplet form found that all passed the USP requirements for proper
disintegration.
Supplements for people
Among the Approved products for people, the cost to obtain 1,000 mg of l-lysine
was as high as 33 cents. However, the following products provided l-lysine at
much lower cost and represent the best value: Spring Valley [Walmart] L-Lysine (4
cents for a 1,000 mg tablet); Puritan's Pride L-Lysine (5
cents for a 1,000 mg caplet). If you want a lower dose, Swanson
Free-Form L-Lysine offers the best value with a capsule providing 500
mg for about 3 cents, and Vitacost
L-Lysine provides a similar product for 4 cents. If you want to mix
L-lysine into a drink or foods, Carlson L-Lysine is a powder
providing 1,000 mg per level scoop (equal to 1/2 teaspoon) at a cost of 8 cents
per scoop.
For cats
For cats, the products were chews. These contain lower doses of L-lysine than
products for people and are more expensive per gram of l-lysine. The best value
was from Pet Naturals of Vermont L-Lysine for Cats — 12 cents
for a 250 mg chew. If you want a lower dose chew, 21st Century L-Lysine
— All Cats, provides 125 mg of l-lysine for 9 cents. Keep in mind that
while these products are Approved for Quality by ConsumerLab.com, there is no
clinical evidence that L-lysine supplementation help prevent or treat feline
herpesvirus 1 infection (see What It Does, For cats).
Test Results by Product:
Listed
alphabetically below are the test results for 19 L-lysine products.
ConsumerLab.com selected 12. Seven products (each indicated with a CL flask)
are included for having passed the same testing through ConsumerLab.com's
voluntary Quality Certification Program. Also listed is
one product which is similar to another which passed testing.
Shown for each product is the labeled amount of L-lysine per pill or other
serving unit as well as the suggested serving size, the price, and the
calculated cost to obtain 1,000 mg of L-lysine. The full list of ingredients is
available for each product by clicking on the word "Ingredients" in
the first column. Products listed as "Approved" met their label claim
for L-lysine, met FDA labeling requirements and all tablets and caplets were
able to properly break apart in solution.
|
RESULTS OF CONSUMERLAB.COM TESTING OF L-LYSINE SUPPLEMENTS AND
CAT CHEWS |
|||||
|
Product Name, Amount
of L-Lysine per Unit, Serving Size, and Suggested Daily Serving on Label |
Claimed Amount of
L-Lysine Per Suggested Daily Serving on Label |
--TEST RESULTS-- |
Cost for Daily
Suggested Serving on Label |
||
|
OVERALL RESULTS: |
Contained Listed
Amounts of L-Lysine |
Disintegrated
Properly |
|||
|
Lysine Supplements: |
|||||
|
|
400 mg2 |
APPROVED |
|
NA |
$0.132 |
|
|
960 mg |
APPROVED |
|
NA |
$0.08 |
|
|
1,000 mg |
APPROVED |
|
|
$0.10 |
|
|
500 mg |
NOT |
Found only 416 mg of
lysine per daily serving (83.2% of listed amount)3 |
NA |
$0.20 |
|
|
1,000 mg |
APPROVED |
|
|
$0.09 |
|
|
1,000 mg to 3,000 mg |
APPROVED |
|
|
$0.11-$0.33 |
|
|
500 mg |
APPROVED |
|
|
$0.08 |
|
|
1,000 mg to 2,000 mg |
APPROVED |
|
|
$0.05-$0.10 |
|
|
1,000 mg |
APPROVED |
|
|
$0.08 |
|
|
500 mg to 1,500 mg |
APPROVED |
|
|
$0.07-$0.22 |
|
|
500 mg |
APPROVED |
|
NA |
$0.08 |
|
|
1,000 mg to 2,000 mg |
APPROVED |
|
|
$0.11-$0.22 |
|
|
500 mg to 1,000 mg |
APPROVED |
|
NA |
$0.05-$0.09 |
|
|
1,000 mg |
APPROVED |
|
NA |
$0.04 |
|
|
1,000 mg to 1,500 mg |
APPROVED |
|
NA |
$0.07-$0.10 |
|
|
500 mg |
APPROVED |
|
|
$0.06 |
|
|
500 mg |
APPROVED |
|
NA |
$0.04 |
|
Similar to Approved Products*: |
|||||
|
Vitamin World L-Lysine (1,000 mg per coated
caplet; 1 coated caplet, once to twice daily) |
Similar to Puritan's
Pride® L-Lysine 1000 mg. |
$0.12-0.23 |
|||
|
Lysine Chews for Cats: |
|||||
|
|
125 mg2 |
APPROVED |
|
NA |
$0.092 |
|
|
250 mg to 500 mg |
APPROVED |
|
NA |
$0.12-$0.23 |
|
|
|||||
|
Unless otherwise noted, information about the products
listed above is based on the samples purchased by ConsumerLab.com (CL) for
this Product Review. Manufacturers may change ingredients and label
information at any time, so be sure to check labels carefully when evaluating
the products you use or buy. If a product's
ingredients differ from what is listed above, it may not necessarily be of
the same quality as what was tested. |
|||||
|
Copyright ConsumerLab.com, LLC, 2016. All rights reserved.
Not to be reproduced, excerpted, or cited in any fashion without the express
written permission of ConsumerLab.com LLC. |
|||||
ConsumerTips™:
What to
Consider When Buying:
From supplements
As nearly all L-lysine supplements provide lysine from the same source:
L-lysine HCl (also called L-lysine hydrochloride or L-lysine
monohydrochloride), there is not much difference among products and you can
focus on choosing a product which is accurately labeled and provides lysine at
the lowest cost. You can also choose between tablets/caplets, capsules, or
powders (products for cats are typically chews).
In the Results table above, the first column shows you the form and amount per
serving in each product. The third column indicates whether or not the product
was Approved by CL for quality. The last column allows you to compare price:
the amount at the top shows the cost per pill or unit (such as a scoop), the
amount in brackets shows the cost to obtain 1,000 mg of L-lysine. Also noted
are special claimed features, such as no wheat, "gluten free," and
"yeast free."
Lysine in food
You can easily get 1,000 mg or more of L-lysine per day by including
protein-rich foods in your diet. The table below shows amount of L-lysine in
common foods.
|
Food |
L-lysine |
|
Soy protein isolate |
5,330 |
|
Beef, top round steak, grilled |
3,130 |
|
Pork loin, roasted |
2,470 |
|
Canned tuna |
2,440 |
|
Wild salmon, cooked |
2,440 |
|
Chicken breast, oven roasted |
1,340 |
|
Parmesan cheese, grated |
2,200 |
|
Muenster cheese |
2,140 |
|
Mozzarella cheese part skim |
1,030 |
|
Whole egg, fried |
990 |
|
Tofu, firm |
880 |
|
Peanuts |
850 |
|
Sunflower seeds, roasted |
820 |
|
Almonds, dry roasted |
560 |
|
Black beans |
560 |
|
Brown rice flour |
280 |
|
Apricot, dehydrated |
340 |
|
Yogurt, plain, whole milk |
310 |
|
Bread, wheat bran |
310 |
Although some laboratory research suggests that lysine may inhibit the herpes
simplex virus by blocking the amino acid arginine (Griffith, Chemotherapy 1981) and several of
the foods listed above also contain arginine (such as peanuts and seeds), there
is no evidence that consuming any of these foods will cause herpes sores.
What to Consider When Using:
Dosage
·
To help prevent herpes cold sores (and genital sores) — 1 gram
of L-lysine daily or up to 3 times daily has been used, taken for a period of
months.
·
To enhance calcium absorption — 400 to 800 mg of L-lysine
daily
·
For cats to prevent/treat feline herpesvirus 1 — There is no
evidence that this is useful (Bol, BMC Veterinary Research 2015).
Labeling on many L-lysine
supplements (and other amino acid supplements) suggests that it be taken on an
empty stomach. The basis for this is a theoretical concern over potential competition for
absorption with certain other amino acids.
Concerns and Cautions:
·
Lysine naturally occurring in foods, such as those high in
protein, has not been associated with adverse reactions. Diarrhea and abdominal
pain have been reported at oral doses of lysine supplements of 1 gram or more (Thein, Oral Surg Oral Med Oral Pathol
1984; Milman, Acta Derm Venereol 1980). There do not appear to be
long-term safety studies on lysine supplementation and maximum safe doses in
women who are pregnant or breastfeeding, and young children, have not been
established.
·
There is one report of kidney dysfunction (Fanconi syndrome) and
progressive kidney failure associated with high-dose, long-term oral lysine
supplementation (3 grams daily for 5 years) (Lo, Am J Kidney Dis 1996)
·
Be aware that lysine may increase calcium absorption when taken
with calcium supplements (Civitelli, Nutrition
1992).
·
In animal studies, high doses of lysine have been found to
gallstones and increased cholesterol levels, so people prone to these
conditions may want to use with caution. People with glutaric acidemia type I,
an inherited disorder which stops the body from processing certain proteins
properly, including lysine, should not take lysine supplements (Tome, J Nutr 2007).
Information on this site
is provided for informational purposes only. It is not an endorsement of any
product nor is it meant to substitute for the advice provided by physicians or
other healthcare professionals. The information contained herein should not be
used for diagnosing or treating a health problem or disease. Consumers should
inform their healthcare providers of the dietary supplements they take.