Also indexed as: Fever Blisters, Herpes Simplex 1 Virus
As soon as a cold sore appears, you’re ready for it to
disappear. According to research or other evidence, the following self-care steps may help
reduce recurrences, speed healing, and put that smile back on your face:
- Look into lysine
- 1,000 mg a day of this amino acid supplement may reduce
recurrences by suppressing the virus that causes sores
- Eat fewer high-arginine foods
- Deprive the virus of this essential nutrient by limiting your
intake of nuts, peanuts, and chocolate
- Try on topicals
- Apply products containing lemon balm, zinc sulfate, vitamin E, or
witch hazel several times a day to reduce pain and speed healing
- Fight back with flavonoids and vitamin C
- Speed healing time by taking 200 mg of each of these healthful
supplements several times a day
These recommendations are not comprehensive and are not intended to replace
the advice of your doctor or pharmacist. Continue reading the full cold sores article for more
in-depth, fully-referenced information on medicines, vitamins, herbs, and dietary and
lifestyle changes that may be helpful.
About cold sores
Cold sores are painful fluid-filled blisters that form on the borders of the lips caused by
a herpes virus, most often the herpes simplex 1 virus.
Cold sores should not be confused with canker
sores, which are small ulcerations in the mouth. The blisters, which are contagious, later
break, ooze, and crust over before healing. Recurrences are common and can be triggered by
stress, sun exposure, illness, and menstruation.
Genital herpes infection (usually caused by herpes simplex 2) is a related condition and
potentially may be treated in much the same way as herpes simplex 1.
Product ratings for cold
What are the symptoms?
Cold sores may appear with colds, fevers, exposure to excessive sunlight, or menstrual
periods, as well as during periods of stress or illness. The sores usually disappear within
two weeks. Initially, there may be tingling or prickling at the site of the cold sores even
before they are visible (called the prodrome); afterward, the blisters often weep a clear
fluid and form a scab. If the infection is
transmitted to the eyes, it may lead to blindness.
The over the counter topical agents docosanol (Abreva®) and allantoin
(Herpecin-L®), as well as camphor and phenol combinations (Campho-Phenique®), help
relieve pain and might promote healing of cold sores. Analgesics, such as aspirin (Bayer®, Ecotrin®, Bufferin®),
ibuprofen (Motrin®, Advil®), and acetaminophen (Tylenol®), might provide some
Antiviral prescription medications such as
topical acyclovir (Zovirax®), topical
penciclovir (Denavir®), oral acyclovir
(Zovirax®), or valacyclovir
(Valtrex®) might reduce the duration of the sores.
Dietary changes that may be helpful
The herpes simplex virus has a high requirement for the amino acid, arginine. On the other hand, the amino acid, lysine, inhibits viral replication.1
Therefore, a diet that is low in arginine and high in lysine may help prevent or treat herpes
outbreaks. Several studies have shown that increasing lysine intake can reduce the recurrence
rate of cold sores.2 Although people with herpes simplex reportedly consume about
the same amount of arginine and lysine in their diet as do people without cold
sores,3 it is conceivable that adjusting the intake of these amino acids may be
beneficial. For that reason, many doctors advise people with cold sores to avoid foods with
high arginine-to-lysine ratios, such as nuts,
peanuts, and chocolate. Nonfat yogurt and other nonfat dairy can be a healthful way
to increase lysine intake.
Vitamins that may be helpful
The amino acid, lysine, has been reported to reduce the recurrence
rate of herpes simplex infections in both
preliminary4 5 and double-blind trials.6 7 The
amount used in these studies was usually 1 to 3 grams per day, although some people received
as little as 312 mg per day. In one double-blind trial, lysine supplementation (1,200 mg per
day) failed to prevent recurrences better than placebo.8 However, the results of
that study may have been skewed by a large number of dropouts in the placebo group who fared
poorly but were not included in the analysis.
When lysine has been used for acute outbreaks, the results have been mixed. In a
preliminary study, 390 mg of lysine taken at the first sign of a herpes outbreak resulted in
rapid resolution of the cold sores in all cases.9 However, in a double-blind study,
supplementing with 1 gram of lysine per day for five days did not increase the healing rate of
the cold sores.10
Vitamin C has been shown to inactivate
herpes viruses in the test tube.11 In one study, people with herpes infections
received either a placebo or 200 mg of vitamin C plus 200 mg of flavonoids, each taken three to five times per day.
Compared with the placebo, vitamin C and flavonoids reduced the duration of symptoms by
Zinc preparations have been shown to
inhibit the replication of herpes simplex in the test tube.13 In one study, people
with recurrent herpes simplex infections applied a zinc sulfate solution daily to the sores.
After healing occurred, the frequency of applications was reduced to once a week for a month,
then to twice a month. During an observation period of 16 to 23 months, none of these people
experienced a recurrence of their cold sores.14
Zinc oxide, the only commercially available form of zinc for topical application, is
probably ineffective as a treatment for herpes simplex.15 Other forms of topical
zinc can be obtained by prescription, through a compounding pharmacist. However, because an
excessive concentration of zinc may cause skin irritation, topical zinc should be used only
with the supervision of a doctor knowledgeable in its use.
In a preliminary trial, a piece of cotton saturated with vitamin E oil was applied to newly erupted cold sores
and held in place for 15 minutes. The first application was performed in the dentist’s
office. Participants were instructed to repeat the procedure every three hours for the rest of
that day, and then three times daily for two more days. In nearly all cases, pain disappeared
in less than eight hours. Application of vitamin E oil appeared to accelerate healing of the
cold sores.16 Similar results were reported in another study.17
Application of an ointment containing
propolis, the resin collected by bees from trees, has been shown to relieve genital herpes
more effectively than topical
acyclovir.18 It is likely that this treatment might also benefit people with
cold sores, although this has not been tested. Propolis ointment should be applied four times
Boric acid has antiviral activity. In a
double-blind trial, topical application of an ointment containing boric acid (in the form of
sodium borate) shortened the duration of cold sores by about one-third.19 However,
concerns about potential toxicity have led some doctors to avoid the use of boric acid for
A preliminary study found that people with recurrent cold sores have lower iron stores than healthy people.20 This may
mean that correcting an iron deficiency might help prevent herpes outbreaks, but more research
is necessary. Most people should not take iron supplements unless they have an iron
deficiency, confirmed by a blood test.
Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful
Lemon balm has antiviral properties. A
cream containing an extract of lemon balm has been shown in double-blind trials to speed the
healing of cold sores.21 In one double-blind trial, topical application of a 1%
70:1 extract of lemon-balm leaf cream, four times daily for five days, led to significantly
fewer symptoms and fewer blisters than experienced by those using a placebo
cream.22 In most studies, the lemon-balm cream was applied two to four times per
day for five to ten days.
The proanthocyanidins in witch hazel have been shown to exert significant
antiviral activity against herpes simplex 1 in the test tube.23 In a double-blind
trial, people with acute cold sore outbreaks applied a topical cream containing 2% witch hazel
bark extract or placebo six times a day for three to eight days.24 By the end of
the eighth day, those using the witch-hazel cream had a pronounced and statistically
significant reduction in the size and spread of the inflammation when compared to the placebo
Licorice in the form of a cream or gel may
be applied directly to herpes sores three to four times per day. Licorice extracts containing
glycyrrhizin or glycyrrhetinic acid should be used, as these are the constituents in licorice
most likely to provide activity against the herpes simplex virus. There are no controlled
trials demonstrating the effectiveness of this treatment, but a cream containing a synthetic
version of glycyrrhetinic acid (carbenoxolone) was reported to speed healing time and reduce
pain in people with herpes simplex.25
In traditional herbal medicine, tinctures of various herbs, including chaparral, St. John’s wort, goldenseal, myrrh, and echinacea, have been applied topically to herpes
outbreaks in order to promote healing.
An extract from elderberry leaves, combined
with St. John’s wort and soapwort (Saponaria officinalis), has been found to
inhibit the herpes simplex virus in the test tube.26 However, the effect of these
herbs on cold sores has not been studied.
Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.
1. Tankersley RW Jr. Amino acid requirements of herpes simplex virus in
human cells. J Bacteriol 1964;87:609–13.
2. Flodin NW. The metabolic roles, pharmacology, and toxicology of
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6. Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy
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