Zinc Lozenges as a Common Cold Treatment

By George Eby

Email: george.eby “at” george-eby-research.com

Revision date: May 27, 2008

Purpose: Zinc lozenges have only one basic use, that being a common cold treatment. The table below is a review of commercial zinc lozenges sold in retail stores in the United States or on the Internet. In academic/medical journals over the last 20 years, the response from zinc lozenges in common cold treatment has ranged from a 7 day reduction in duration of common colds, to a 4. 5 day increase in the duration of common colds, worsening colds. Most zinc lozenges marketed have chemistry similar to the lozenges tested in those 15 clinical trials. Consequently, the buyer of zinc lozenges may purchase lozenges that worsen colds, do nothing, or shorten the duration of colds. Careful study of this analysis will be useful in identifying the zinc lozenge right for you.

Background: The only biological effects of zinc lozenges are due to ionic zinc (iZn), which is available at physiologic pH 7.4 only from a few zinc compounds, mainly zinc acetate and zinc gluconate. The biological effects of ionic zinc include antirhinoviral, ICAM-1 inhibition, and interferon induction and immune system benefits. No other zinc compounds release sufficient ionic zinc at physiologic pH 7.4 (pH of mouth and nose) to have a beneficial effect as a common cold treatment. Response to the zinc lozenges is believed completely dependent upon the zinc lozenge chemistry in the formulations and dosages used and the time of zinc lozenge oral dissolution. The lozenges must slowly dissolve over a 20 to 30 minute time period for efficacy to be observed, because only the ionic zinc absorbed into the oral tissues, which requires time, has any benefit in treating colds. Swallowed zinc has no effect on colds. Swallowing zinc is not necessary for efficacy to result. The chemistry of zinc lozenges is very complicated (solution equilibrium chemistry – a branch of inorganic biochemistry) and is well beyond the training and scope of nearly all zinc lozenge manufacturers and formulators. The interested chemist/scientist/physician can learn something about this science by reading "Zinc Lozenges: Cold Cure or Candy” Solution Chemistry Determinations”. Other applicable data sources are found here. All of the zinc lozenges found on this page are believed to provide nutritional support.

Zinc compounds used in lozenges: Most zinc lozenges are marketed as “zinc gluconate”, “zinc gluconate-glycine” or “zinc acetate” lozenges, although there are several other types on the market. One would expect to receive “zinc gluconate” when one purchases “zinc gluconate” lozenges, and “zinc acetate” when one buys “zinc acetate” lozenges. However, manufacturers nearly always add other ingredients, such as food acids designated as “inactive” ingredients, usually to improve lozenge flavor or to increase market appeal, for example by adding vitamin C (ascorbic acid), or other ingredients. These “inactive” ingredients are actually very “active” chemically and they react with the highly ionizable zinc compounds used to produce other zinc compounds through solid state reactions after the zinc lozenges are manufactured. These reactions continue from the date of manufacturer until usage, and they may also occur in the saliva of people using those zinc lozenges. These other ingredients are necessary flavor masks in zinc gluconate lozenges since zinc gluconate reacts with all carbohydrate sweeteners (except fructose) to form very bitter compositions. Consequently, the other ingredients act as flavor masks by converting the zinc gluconate to another zinc compound that does not have the terribly bitter taste of zinc gluconate. Citric acid, ascorbic acid and glycine are the usual flavor masks; and glycine always diminishes or eliminates iZn, while citric and ascorbic acid usually completely eliminate ionic zinc (iZn), rendering the product useless. Zinc acetate lozenges are flavor stable and pleasant tasting without added chemicals and provide a much better source of ionic zinc, yet zinc acetate is relatively uncommon in zinc lozenges. The consequence of these added ingredients are known to solution chemists (since they can calculate it based on libraries of solution chemistry data ), but these consequences are usually not known to other scientists, manufacturers, formulators, physicians or the public.

What zinc compounds release bioactive ionic zinc (iZn)? The mouth knows! Ionic zinc (the active ingredient) always tastes astringent and orally drying and metallic. Lozenges containing substantial iZn do not taste like candy!

Analysis of zinc lozenge compositions using solution equilibrium chemistry techniques produced the following amount of ionizable zinc (iZn - the active ingredient) at physiologic pH 7.4:

·   Zinc acetate yields 100% iZn.
·   Zinc gluconate yields 72% iZn.
·   Zinc gluconate-glycinate yields <57% iZn.

·   Zinc gluconate + citric acid (or zinc citrate) yields 0% iZn.
·   Zinc ascorbate yields 0% iZn
·   Zinc aspartate yields 0% iZn.
·   Zinc oxide yields 0% iZn.

NOTICE: Manufacturers may change their formulas without notice, and the reader is recommended to check the list of “inactive” ingredients and search for additives that may result in a change in zinc lozenge chemistry (mainly food acids such as amino, citric and ascorbic acids, as well as inactive zinc compounds like zinc oxide, zinc aspartate, zinc citrate and zinc ascorbate). These data in the table below are believed accurate and they use the best information available, but without much more clinical data on efficacy, there remain questions that must remain unanswered and there may be some incorrect assumptions and expectations.

None of these products are recommended for serious diseases such as influenza.

Safety of zinc lozenges: The use of large amounts of zinc (as may occur with use of these zinc lozenges) for 7 days or less is not believed to be harmful according to Dr. Ananda S. Prasad, MD, PhD, the godfather of zinc biochemistry, and these large doses may result in other observed benefits such as elimination of menstrual cramping and bloating in women and elimination of angina pectoris and Reynaud’s disease, showing important cardiovascular benefits. However, extended use, (for considerably longer than 1 week) is not recommended since reversible immune system impairment may occur with extended use of high dose zinc.  The main side effect of large doses of zinc is nausea, which may become sufficiently severe to cause prolonged vomiting, which is an indication of zinc overdose. If overdose occurs, immediately stop ingesting zinc.

Lack of safety of intranasal zinc (nose drops, nasal sprays, nasal gels): This table does not include information on zinc nose drops, zinc nasal sprays, or zinc nasal gels. Intranasal zinc has been known since before 1938 to carry a risk of anosmia (loss of the sense of smell). This means spraying ionic zinc into the nose may result in contact of the zinc with the olfactory bulb which is in the top of the nose, which will cause excruciating, unremitting pain and persistent anosmia (loss of the sense of smell) which appears to be a permanent condition. Much more information is available here.

The big table below: The following huge table presents the zinc lozenge products found on the Internet and analyses them chemically from the list of ingredients given by the manufacturer, and shows the author’s expert opinion of what results he expects from use of those lozenges. George Eby’s expert status on zinc lozenges and common cold treatment can be verified at the eTblast expert finder which uses the rank number of academic/medical journal articles published to determine expertise.

Invention! George Eby invented zinc lozenges as a cure for common colds (U.S. Patent # 5409905). There are no active, basic patents on zinc lozenges as a common cold treatment remaining. To see all of George Eby’s medical journal articles, click here. To go to George Eby's home page (many natural treatments for diseases) click here. The table below presents:

(1) the product (with a link to a sales site) / manufacturer,
(2) George Eby’s expert opinion of what results he expects and alternative possibilities or suggestions for use,
(3) directions on zinc lozenge packaging and any alternative directions,
(4) the zinc compound listed on the label (with link to solution chemistry computation of zinc compound used),
(5) the zinc compound expected after reactions with “inactive” lozenge ingredients (with link to solution chemistry computation of zinc compound expected), and milligrams of iZn (the active ingredient) per lozenge,
(6) a link to the academic/medical journal article most nearly representing the product from the perspective of the chemistry of the lozenge, and
(7) comments.

How listed? Zinc lozenges are listed according to the amount of iZn available from each zinc lozenge, which may or may not correlate with efficacy. Be certain to check out the least effective, because it may substantially increase the duration of colds.

For more information: Send email to: george.eby “at” george-eby-research.com

Product name Distributor	Expected Results Against Common Colds	Directions on Label	Zinc compound claimed on label	Zinc compound (mg) expected after reacting with other lozenge ingredients & mg iZn	Academic / medical research article most applicable to product	Comments “manufacturer’s comments” Eby comments (without quotation marks)
ColdCure® by Eby Pharma LLC (out of stock)	5 to 7 day reduction in duration of common colds and reduction in severity of all common cold symptoms when used as directed. Their benefits extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits lasting for 3 to 6 hours in allergy treatment.	START THERAPY WITH 2 LOZENGES, ONE AFTER ANOTHER, AT THE FIRST SIGN OF A COLD (A SCRATCHY THROAT). After initial dose slowly dissolve one lozenge in mouth every two hours, with one before bedtime – maximum 8 lozenges / day [144 mg elemental zinc]. Do not skip doses or stop taking doses until common cold symptoms have been absent for 6 hours.	Zincum aceticum 2X (zinc acetate) (18 mg zinc)	Zincum aceticum 2X (zinc acetate) 18 mg iZn	Prasad 2000 Petrus 1998 Prasad 2008 ColdCure® Lozenges are much stronger than the lozenges tested by Prasad (12.8 and 13.3 mg iZn) and the 9 mg lozenges tested by Petrus.	These are sweet, peppermint flavored lozenges, but are astringent, drying and metallic tasting, which are representative of iZn. These are the strongest, best tasting zinc lozenges available. They contain fructose and are the sweetest zinc lozenge. They are labeled and marketed as a homeopathic common cold treatment A “boutique” and rare homeopathic drug product without retail distribution.
Zinx® Lozenges By Auriga Laboratories (out of production)	3 to 4 day reduction in duration of common colds and reduction in severity of all common cold symptoms when used as directed. Their benefits extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits lasting for 3 to 6 hours in allergy	START THERAPY WITH 2 LOZENGES, ONE AFTER ANOTHER, AT THE FIRST SIGN OF A COLD (A SCRATCHY THROAT). After initial dose slowly dissolve one lozenge in mouth every two hours, with one before bedtime	Zincum aceticum 2X (zinc acetate) (14 mg zinc)	Zincum aceticum 2X (zinc acetate) 14 mg iZn	Prasad 2000 Petrus 1998 Prasad 2008 Zinx® Lozenges are stronger than the lozenges tested by Prasad (12.8 and 13.3 mg iZn) and the 9 mg lozenges tested by Petrus.	These were peppermint flavored lozenges, and were astringent, drying and metallic tasting, which are representative of iZn. These were the second strongest zinc lozenges available. They were labeled and marketed as a homeopathic common cold treatment.
Fast Dry™ Zinc Lozenges By F&F Foods: (out of production)	3 to 4 day reduction in duration of common colds and reduction in severity of all common cold symptoms when used as directed. Benefits extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits lasting 2 to 4 hours. No common cold claims are allowed by the manufacturer.	Allow one lozenge to dissolve in the mouth every 2 hours.	zinc acetate (14 mg zinc)	zinc acetate 14 mg iZn	Prasad 2008 Fast Dry™ Lozenges are slightly stronger (14 mg iZn) than the lozenges tested by Prasad (12.8 and 13.3 mg iZn) and substantially stronger than the 9 mg zinc lozenges tested by Petrus. F&F Foods made the 13.3 mg zinc acetate lozenges tested by Prasad in 2008.	These were pleasant cherry flavored hard candy (not compressed) lozenges, but were astringent, drying and metallic tasting, which are representative of iZn. These were the only effective hard candy zinc lozenges available. No drug claims and no marketing support.
Zicam Rapid Melts ® By Matrixx Initiatives.	One day reduction in duration with reduction in symptom severity when used as directed. If patients hold zinc-laden saliva in mouth for 30 minutes or longer each use, reductions in duration of 3 to 5 days may result. Its benefits are likely to extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits in allergy treatment lasting for 2 to 4 hours.	Dissolve entire tablet in mouth. Do not chew. Do not swallow whole. Take one tablet at the onset of symptoms. Repeat every three hours until symptoms are gone. For best results, use for an additional 48 hours after symptoms subside. Do not eat or drink 15 minutes after use. Do not eat or drink citrus fruits or juices for 30 minutes before or after. Otherwise, drink plenty of fluids. Homeopathic treatment for common colds	Zincum Aceticum, (zinc acetate Zincum Gluconicum (Zinc Gluconate) (13.3 mg zinc)	Zincum Aceticum, (zinc acetate) Zincum Gluconicum (Zinc Gluconate) 10.4 mg iZn	None. Clinical trials are needed to support manufacturer claims of efficacy in reducing the duration and severity of common colds. Since Fick’s laws of membrane permeability apply, little results can be expected when a necessary variable “time of contact” approaches zero.	Tablet dissolves too fast for significant oral absorption of ionic zinc to have major impact on duration of colds. Nearly all is swallowed. Reasonably pleasant zinc gluconate taste with offensive zinc gluconate aftertaste. The longer the zinc laden saliva is held in mouth, the better the results will be. To avoid minor stomach upset, do not take on an empty stomach.
Cold-Free® zinc acetate lozenges Great American Nutrition (out of production)	One to two days day reduction in duration with reduction in symptom severity when used as directed. Its benefits are likely to extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits in allergy treatment lasting for 2 to 4 hours.	Allow one lozenge to dissolve in the mouth every 1 to 1.5 hours.	zinc acetate (9 mg zinc)	zinc acetate 9 mg zinc	Petrus 1998 Cold-Free® zinc acetate lozenges were the 9 mg lozenges tested by Petrus.	These were sweet, hard candy and compressed highly flavored lozenges, but were astringent, drying and metallic tasting, which are representative of iZn. These lozenges were removed from the market because the FDA held that the name “Cold-Free” was an unauthorized drug claim and because the company would not avail itself of the homeopathic drug laws.
Cepacol® ColdCare^TM zinc acetate lozenges (out of production)	One to two days day reduction in duration with reduction in symptom severity when used as directed. Its benefits are likely to extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits in allergy treatment lasting for 2 to 4 hours.	Allow one lozenge to dissolve in the mouth every 1 to 1.5 hours.	Zincum aceticum 2X (zinc acetate) (9 mg zinc)	zinc acetate 9 mg zinc	Petrus 1998 Cold-Free® zinc acetate lozenges were the 9 mg lozenges tested by Petrus.	These were sweet, compressed lozenges, but were astringent, drying and metallic tasting, which are representative of iZn. These lozenges were removed from the market because the FDA held that the name “Cold-Free” was an unauthorized drug claim and because the company would not avail itself of the homeopathic drug laws.
Cold-Eeze ® by Quigley	“Get well faster” One to two days reduction in duration and reduction in symptoms severity. Its benefits are likely to extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits in allergy treatment lasting for 2 to 4 hours.	For maximum effectiveness start taking lozenges at the first sign of a cold. Best within 48 hours. Completely dissolve a lozenge in mouth. Do not chew. Repeat every 2 to 4 hours as needed. Recommended daily dose of lozenges is 6 drops per day. Homeopathic common cold treatment	Zinc Gluconate Glycine (13.3 mg zinc)	Zinc Gluconate Glycine 7.6 mg iZn	Godfrey 1992 (original ZGG trial) Macknin 1998 (Children’s Cold Eeze®) McElroy 2003 (Children’s Cold Eeze®) This is the most tested zinc lozenge product, and it is the market leader. There are no indications of harmfulness in any of the published medical literature reviewed.	The 3 to 4 day reduction in duration and “42% reduction” claimed are believed overstated. There has been wide variation in clinical trial results of Cold-Eeze, with results ranging from a half day increase in duration to 3 days reduction in duration as shown in this 2004 report. There are a variety of Cold-Eeze® products, and some have not been clinically tested.
Zinc Lozenges By Walgreens	“Get well faster” One to two days reduction in duration and reduction in symptoms severity. Its benefits are likely to extend to reduction in respiratory allergy symptoms, with each lozenge providing benefits in allergy treatment lasting for 2 to 4 hours.	For best results, begin treatment at start of symptoms (within 24 to 48 hours) of onset. Repeat every 2 to 4 hours as needed until symptoms subside. Completely dissolve a lozenge in mouth (do not chew). Recommended daily dose of lozenges is 6 lozenges for adults and 4 lozenges for ages 12-17. Children under 12 years of age should consult a health professional before use Homeopathic common cold remedy.	Zinc Gluconate Glycine (13.3 mg zinc)	Zinc Gluconate Glycine 7.6 mg iZn	Godfrey 1992 (original ZGG trial) Macknin 1998 (Children’s Cold Eeze®) McElroy 2003 (Children’s Cold Eeze®)	This appears to be an exact copy of the Quigley Cold Eeze product. “Lozenges are formulated to reduce the duration of common cold symptoms and may be insufficient treatment for influenza or allergies.” NOTE: No zinc lozenge is sufficient for influenza, and this label comment may be viewed critically by the FDA. This product should be effective against allergies for 4 to 6 hours.
Zeus Zinc Lozenges By Olympian Labs Products	No benefit expected.	Zinc lozenges are most effective if taken at the first sign of symptoms, ideally within 24 hours. Then it is recommended that a lozenge be taken every two hours while awake for maximal efficacy.	Zinc Gluconate (1 mg zinc)	Zinc Gluconate 0.72 mg iZn	None. There are no clinical trials in support of this product.	“Zinc Lozenges may help you through tough cold seasons as well as relieve symptoms from allergies. Zinc has been shown to reduce the average duration of colds and reduce the severity of cold symptoms.”
Cold Tablets with Zinc By Hyland’s	No benefit expected.	Adults: Dissolve 2 to 3 tablets under tongue every 4 hours or as needed. Children 6 to 12 years: 1/2 adult dose. Homeopathic. 100% Natural, no side effects. Soft tablets dissolve instantly. This all natural homeopathic formula works without side effects and won't interact with other medications-day or night.	Zinc Gluconate (0.24 mg zinc)	Zinc Gluconate 0.18 mg iZn	None. There are no clinical trials in support of this product.	Active Ingredients: Aconitum Napellus 6x HPUS, Allium Cepa 6x HPUS, Zinc Gluconate 6X HPUS, Gelsemium Sempervirens 6X HPUS. “Hyland's Cold Tablets with Zinc Quick dissolving tablets provide fast natural relief from symptoms of the common cold.”
No Time for Colds ® By SmartScience Laboratories, Inc.	Symptomatic relief starting in the first day of treatment, but no reduction in duration of common cold symptoms.	Begin at first sign of cold. Dissolve lozenge in mouth. Repeat in 30 minutes and each 3 hours. Up to 5 lozenges per day. Homeopathic common cold treatment	Zinc Gluconate (13.1 mg zinc)	Zinc citrate 0 mg iZn	Turner 2004 The only difference between the product Turner studied and this product is the addition of citric acid as a flavor mask, which eliminates all iZn. There should be no differences in results.	The symptomatic relief is believed produced by troxerutin, one of the inactive ingredients. “There is NO unpleasant metallic aftertaste like that experienced when taking many of the other zinc cold remedies.”
Halls Defense By Halls	No benefit expected No common cold claims are made by the manufacturer.	As a dietary supplement for adults, take 1 drop 4 times per day.	Zinc sulfate	Zinc citrate Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product.	Do not use for more than 8 weeks consecutively. Do not use if you have a severe systemic illness. Do not use if you have allergies to the daisy family (Asteraceae). Do not use if you are pregnant or breast feeding.
Ultra Zinc® Lozenges by GNC	No benefit expected No common cold claims are made by the manufacturer.	As a dietary supplement, take two to six lozenges daily, preferably after a meal. Allow the lozenge to dissolve slowly in the mouth. Do not chew.	Zinc oxide (20 mg zinc)	Zinc oxide 0 mg iZn	None. There are no clinical trials in support of this product.	Zinc oxide is only slightly soluble in water, and is essentially non-ionizable and does not release zinc ions (iZn) sufficient to have an effect on common colds or rhinoviruses.
Chelated Zinc Lozenges By Puritan’s Pride	No benefit expected when used once or twice daily as recommended. May lengthen colds by one day if used too frequently.	Dissolve one lozenge in mouth one or two times daily. Do not exceed two per day.	Zinc citrate and Zinc Gluconate (23 mg zinc)	Zinc citrate and zinc gluconate-citrate 0 mg iZn	Farr 1987	These lozenges should taste like candy and function like candy.
Zinc Lozenges By Arrowroot	No benefit expected. No common cold claims are made by the manufacturer.	Not observed	23mg zinc 100mg of vitamin C	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product.	“Minerals, like vitamins, help our body systems function. They support the proper utilization of vitamins as well as the building of blood, bones and teeth. Minerals also control muscle tone and the maintenance of healthy nerves.
Sootherbs®zinc lozenges by Amerifit.	No benefit expected, although colds might be slightly worsened and might last a half day longer.	Take 1 lozenge every 3-4 hours. Allow lozenge to dissolve in your mouth.	Zinc Liposome; Zinc citrate (10 mg zinc)	Zinc citrate 0 mg iZn	Farr 1987	“THIS PRODUCT IS NOT INTENDED TO DIAGNOSE, TREAT, CURE, OR PREVENT ANY DISEASE.”
Zinc Lozenges By Progressive labs and by Kordial Nutrients	No benefit expected.	As a dietary supplement, two (2) lozenges daily, or as directed by a healthcare practitioner. For short term high-intensity use, one or two (1-2) lozenges every two to four (2-4) hours, dissolving completely in the mouth. Do not exceed 10 lozenges per day or use intense levels for more than 7 days.	Zinc Gluconate (24 mg zinc) Plus 300 mg ascorbic acid	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product.	“Zinc in lozenge form provides enough zinc to nasal tissues to be effective against the common cold.” Zinc gluconate plus ascorbic acid yields insoluble zinc ascorbate in solid state reactions.
Zinc Lozenges By Douglas Laboratories	No benefit expected.	As a dietary supplement, adults take One (1) lozenge every Two (2) hours while awake, or as directed by physician. Allow to dissolve completely in the mouth. Do not exceed Ten (10) per day. Children over the age of Four (4) years may use half the adult dose.	Zinc glycinate (10 mg zinc)	Zinc glycinate 0 mg iZn	None. There are no clinical trials in support of this product.	“Numerous studies support the fundamental role of zinc in normal immune response in humans. Immune cells must be able to rapidly divide in order to respond to daily challenges. Like all rapidly dividing cells, immune cells depend on adequate amounts of dietary zinc.”
Zinc Lozenges with Cherry Flavor by Basic Organics	No benefit expected, although colds might be slightly worsened and might last a day longer.	At first sign of cold symptom, take 2 Zinc lozenges. Dissolve in mouth slowly & completely. Thereafter take 1 Lozenge every 2 hours while awake.	Zinc Citrate (10mg zinc) Zinc Gluconate (5 mg zinc) Citric acid	Zinc citrate and zinc ascorbate 0 mg iZn	Farr 1987	This product carries mixed signals, with advertisement reading to “start at first sign of a cold symptoms” yet it is marketed as a “100% natural dietary supplement with zinc.”
Zinc Lozenges By DaVinci Laboratories	No benefit expected. No common cold claims made.	Take 1 lozenge in AM and 1 lozenge in PM. Let dissolve in mouth.	Zinc Gluconate Zinc Citrate Citric acid	Zinc Citrate 0 mg iZn	Farr 1987	Zinc lozenges are a great tasting lemon flavored supplement for both children and adults.
Elderberry Zinc By Zand®	No benefit expected. No common cold claims made.	Allow lozenge to slowly dissolve in the mouth. May be repeated as needed.	Zinc Gluconate (5 mg)	Zinc citrate 0 mg iZn	Farr 1987	“Sweetened Only With Natural Rice Syrup.”
Zinc Lozenges By Nature’s sunshine	No benefit expected.	Take one lozenge each hour or as needed. Allow lozenge to dissolve slowly in mouth. Do not use more than six lozenges daily.	Zinc Acetate (5 mg zinc) 100 mg ascorbic acid	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product	Zinc - Vitamin C - Echinacea Dietary Supplement
Zinc Lozenges By Jamieson Laboratories	No benefit expected.	Take at the first sign of sore, dry throat, cold or flu. Dissolve lozenge slowly in mouth. Maximum 6 lozenges daily.	Zinc Gluconate (5 mg zinc) (50 mg ascorbic acid)	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product	“ Zinc Lozenges with vitamin C helps boost the immune system's virus fighting power. It helps to reduce the duration and severity of the symptoms associated with the common cold.”
Zinc Lozenges by Nature's Life	No benefit expected.	As a dietary supplement take 2 to 6 lozenges per day, do not take for more than 3 days since long term zinc supplementation may lead to copper deficiency.	Zinc Gluconate (10 mg zinc) (100 mg ascorbic acid)	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product	“Zinc is an essential mineral for a healthy immune system. Vitamin C is an essential antioxidant vitamin that helps maintain the immune system.”
Zinc Lozenges with Vitamins A & C By Basic	No benefit expected.	Directions: Take at first sign of cold symptoms. Dissolve one lozenge in mouth every four hours, or as needed.	Zinc oxide (15 mg)	Zinc oxide 0 mg iZn	None. There are no clinical trials in support of this product	“One Lozenge contains Vitamin A 500 IU. Vitamin C 100mg. Zinc 15mg May shorten length of the common cold. Soothes sore throat. Antioxidant”
Thera Zinc®Cold Season+ Lozenges By Quantum Health	No benefit expected. If used often like other zinc citrate lozenges colds might be worsened & colds might last a day longer.	Slowly dissolve one zinc lozenge in your mouth every two wakeful hours. Do not chew. Adults do not exceed 9 lozenges per day.	Zinc Gluconate (14 mg) Citric acid	Zinc citrate 0 mg iZn	Farr 1987	Internet advertisements do not show presence of citric acid, yet citric acid is shown on product label.
Chelated Zinc Lozenges by Nature’s Bounty	No benefit expected, when only one per day is taken as recommended. If taken frequently, like other zinc “citrate” lozenges, colds might be slightly worsened and colds might last a day longer.	As a dietary supplement, take one tablet daily.	Zinc Gluconate (23 Mg zinc) plus Citric acid	zinc gluconate-citrate 0 mg iZn	Farr 1987	“Provides optimal benefits while minimizing the gastro-intestinal discomfort normally associated with zinc supplementation.”
ZINC LOZENGES + Vitamin C and Echinacea By Sundown	No benefit expected. No common cold claims are made by the manufacturer.	Dissolve one (1) lozenge in the mouth, up to two times per day, after Meals.	Zinc Citrate Zinc Gluconate Plus ascorbic acid	Zinc Citrate Zinc ascorbate 0 mg iZn	Farr 1987	"Lozenges provide an immediate soothing effect on the throat. This formula contains two popular nutrients plus Echinacea. Zinc Lozenges have a delicious citrus flavor and leave no aftertaste."
Zinc Lozenges with Zinc Gluconate By TwinLab	No benefit expected. No common cold claims are made by the manufacturer.	As a dietary supplement, suck one or two lozenges daily, or as directed.	Zinc Gluconate, zinc aspartate (23 mg zinc) Plus citric acid and ascorbic acid	Zinc citrate zinc ascorbate zinc aspartate 0 mg iZn	Farr 1987 McCutcheon 1987	Zinc citrate, zinc ascorbate (non soluble) and zinc aspartate are not ionizable and provide no iZn for use in treating colds. However, these lozenges should taste very good, like candy.
Zinc King By Nutrition Now	No benefit expected. No common cold claims are made by the manufacturer.	As a dietary supplement, take 2 Zinc Cold King lozenges consecutively, letting 1 completely dissolve before taking the other. Thereafter, continue taking 1 lozenge every 2 hours.	zinc citrate and zinc gluconate (15 mg zinc) Plus 100 mg ascorbic acid.	Zinc citrate zinc ascorbate 0 mg iZn	Farr 1987	Zinc Cold King is a zinc-fortified lozenge to nutritionally support the body’s defense system through the winter season. A dietary supplement to promote a healthy immune system.
Zinc Lozenges by Bluebonnet	No benefit expected. No common cold claims are made by the manufacturer.	Use as directed.	zinc gluconate (15 mg zinc) Plus 100 mg ascorbic acid	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product.	This product is not intended to diagnose, treat, cure or prevent any disease
Flavo-Zinc Lemon Lime By Solgar	No benefit expected. No common cold claims are made by the manufacturer. .	As a dietary supplement for adults, one (1) lozenge daily, or as directed by a healthcare practitioner. Lozenge should be allowed to dissolve in the mouth.	Zinc citrate Zinc Gluconate (23 mg zinc) Citric acid	Zinc citrate 0 mg iZn	Farr 1987	“This product is not intended to diagnose, treat, cure or prevent any disease.”
Animal Parade Kid Zinc Lozenges By Nature’s Plus	No benefit expected. No common cold claims are made by the manufacturer.	As a dietary supplement for children, one animal-shaped lozenge once daily or as recommended by your health care practitioner.	Zinc (as zinc aspartate, and zinc mono-methionine) (8 mg zinc)	Zinc (as zinc aspartate, and zinc mono-methionine) 0 mg iZn	McCutcheon 1987	“Each fast-acting lozenge provides 8 mg of the highest quality organically chelated zinc available. KidZinc Lozenges also provide Echinacea, Olive Leaf, Slippery Elm and Ginger.”
Zinc Lozenges By Nature’s Plus	No benefit expected. No common cold claims are made by the manufacturer.	As a dietary supplement, one lozenge daily directly after meals or as directed by your health care professional. Taking zinc lozenges on an empty stomach may cause stomach upset in some individuals.	Zinc aspartate (15 mg zinc)	Zinc aspartate 0 mg iZn	McCutcheon 1987	Keep tightly closed in a cool, dry place. Keep out of reach of children.
Zinc-Ease ® by Carlson Laboratories	No benefit expected, may increase duration of common colds by one day if used as directed.	Slowly dissolve one lozenge in mouth every 2-3 hours, up to 6 per day.	Zinc citrate (10 mg zinc)	Zinc citrate 0 mg iZn	Farr 1987	“Do not take for more than 7 days. If nausea is experienced, discontinue use. Store away from heat and moisture.”
Zinc Lozenges By VitaBase	No benefit expected. No common cold claims are made by the manufacturer.	As a dietary supplement, adults dissolve one (1) lozenge in the mouth as needed, or as directed by a health care professional.	Zinc Gluconate, Zinc citrate (15 mg) ascorbic acid 60 mg	Zinc citrate and zinc ascorbate 0 mg iZn	Farr 1987	“Zinc is an essential mineral and antioxidant, that is also believed to help shorten the duration of cold and sore throat symptoms.”
Zinc Lozenges by Foodscience Of Vermon	No benefit expected, may increase duration of common colds by one day if used as directed.	As a dietary supplement, take 1 lozenge in the morning and 1 lozenge in the evening.	Zinc Gluconate & Zinc citrate Plus citric acid (23 mg Zinc)	Zinc citrate 0 mg iZn	Farr 1987	“Supplemental Zinc may be effective in keeping your immune system in peak working order.”
Zinc Lozenge Plus Vitamin C By Total Nutrition	No benefit expected, may increase duration of common colds by one day if used as directed.	For Cold Symptoms: Adults, take two (2) lozenges, one followed by the other at the onset of cold symptoms. Allow to dissolve in mouth. Take 1 lozenge every two to three hours thereafter.	Zinc citrate (23 mg zinc)	Zinc citrate 0 mg iZn	Farr 1987	“Directions: As a dietary supplement, allow one to two lozenges to dissolve under the tongue daily, or as directed by a health care professional.”
Zinc Lozenges with vitamin C by Country Life	No benefit expected, may increase duration of common colds by one day if used as directed. No common cold drug claims are made by the manufacturer.	Allow one (1) zinc lozenge to dissolve under the tongue. Repeat every two (2) to three (3) hours. Do not take more than six (6) lozenges in one (1) day. Do not take for more than three (3) days.	Zinc (as Zinc Gluconate, Zinc citrate ) (23 mg) (100 mg ascorbic acid)	Zinc citrate and zinc ascorbate 0 mg iZn	Farr 1987	“These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.”
Elderberry & Zinc By Now Foods	No benefit expected. No common cold drug claims are made by the manufacturer.	As a dietary supplement, Adults: Take 2 lozenges daily. For short term high-intensity use, take 1 to 2 lozenges every 2-4 hours, dissolving completely in the mouth. Do not exceed 10 lozenges per day or use intense levels for more than 7 days.	Zinc Gluconate (24 mg zinc) (300 mg ascorbic acid)	Zinc ascorbate 0 mg iZn	None. There are no clinical trials in support of this product.	“* Supports Immune System * Promotes Healthy Immune Function * Support for Seasonal Changes* * A Dietary Supplement Zinc is a trace mineral that plays an important role in supporting the immune system. Echinacea, Propolis and Slippery Elm have been.”
Wellness Zinc Lozenges by Source Naturals	No benefit expected. No common cold drug claims are made by the manufacturer	Use as directed.	as Zinc Gluconate, zinc ascorbate, and zinc amino acid chelate (23 mg zinc) Vitamin C 30 mg Citric acid	Zinc ascorbate, zinc amino acid chelate, Zinc citrate 0 mg iZn	None. There are no clinical trials in support of this product.	“Wellness Zinc Lozenges are specially formulated to contain the most active forms of zinc. Zinc is a trace element that plays a significant role in the human body. It is involved in normal cell growth and repair and helps support the body's natural defenses. Natural lemon-lime flavor has no zinc aftertaste.”
Immun Actin, Zinc Lozenges by Nature’s Plus	No benefit expected No common cold drug claims are made by the manufacturer.	As a dietary supplement offering the consistent benefits if exact potency, one lozenge three times daily or as recommended by your health care professional.	zinc aspartate (10 mg)	zinc aspartate 0 mg iZn	McCutcheon 1987	“The Energy Supplements Herbal Active Standardized Botanical Supplement With Echinacea, Olive Leaf & Elderberry Prescription Quality Delicious Wild Cherry Nutritional Support for General Well Being.”
Zinc Lozenges with Echinacea & Vitamin C By Nature’s Way	No benefit expected, may increase duration of common colds by one day if used as directed. No common cold drug claims are made by the manufacturer.	Recommended Dosage:  Take one lozenge every two hours, up to six lozenges per day. Allow lozenge to dissolve slowly in mouth.  Best used at the onset of throat irritation.  This product should not be used more than 7 days.	Zinc citrate / Zinc Gluconate (23 mg zinc) 100 mg ascorbic acid	Zinc citrate / ascorbate 0 mg iZn	Farr 1987	“Nature's Way Zinc lozenge boosts cold season defense with zinc, widely recognized as an important nutritional support during the cold season, and echinacea pupurea, clinically shown to support the immune system, and Vitamin C, a vitally important vitamin for general health maintenance.”
Zinc Lozenge Plus Formula By Pharmacist	No benefit expected, may increase duration of common colds by one day if used as directed. No common cold drug claims are made by the manufacturer.	Dissolve one lozenge in mouth every three to four hours. Do not exceed six lozenges in a 24 hour period.	Zinc citrate Zinc Gluconate (30 mg zinc) (300 mg ascorbic acid)	Zinc citrate / ascorbate 0 mg iZn	Farr 1987	“Contains Echinacea as an immunomodulator to help support and boost the natural defense system.”
Cold Reduce ® Lozenges by Healthy Relief	No benefit expected.  Inclusion of magnesium ascorbate is expected to worsened colds. Product label suggests that this may occur because label states: “Warnings: Initial exacerbation of symptoms may occur.”  Colds may be expected to last up to 7 days after cessation of product use, based upon asthma article observations of Eby 2006.	Allow one lozenge to completely dissolve in the mouth, do not chew or swallow lozenge whole. Repeat every 2 hours, up to 8 lozenges per day.  “Stop use and ask a doctor if: Symptoms persist or worsen. Any new symptoms appear. Fever lasts for more than 3 days. Cough or nasal congestion lasts more than 7 days.”	Zincum oxydatum (zinc oxide) 1X	Zincum oxydatum (zinc oxide) 1X 0 mg iZn	None. There are no clinical trials in support of this product Warnings: Eby 2006 (Discussion section) Fiala 1967 Clinical trials are needed to support manufacturer claims of efficacy in reducing the duration and severity of common colds.	Fiala 1967 showed that ionizable magnesium increases rhinovirus release from cells by 8 to 310-fold. Eby 2006 showed that ionizable magnesium greatly worsened common colds. Ionizable magnesium, like magnesium ascorbate, should never be used in throat lozenges such as zinc lozenges, since it may greatly worsen and lengthen colds.
“Zinc Lozenges”	Froogle has a list of 4, 026 “zinc lozenge” products	Most are dietary supplements.	Miscellaneous	Miscellaneous	Usually none	“Throat lozenges” are not allowed under the DSHEA of 1994.
The above table is likely to be incomplete, but it is representative of zinc lozenges found in United States retail outlets and on the Internet. Other products will be added upon request.