As a group blog, Science-Based Medicine brings a variety of perspectives to issues of science in medicine. However we align around a few core principles which define what science-based medicine is, and how it should be practiced. One principle we emphasize is the importance of subjecting the evaluation of all health interventions and treatments to a single, science-based standard. One of the biggest successes of the alternative medicine industry, worldwide, has been the embedding of different regulatory standards for the evaluation and approval of so-called “non-drug” products such as supplements, herbal products, and non-scientific treatment systems like homeopathy or traditional Chinese medicine (TCM). The implications cannot be overstated: this different and lower standard is now so firmly entrenched in most health systems that few seem to question its rationale, or consider the consequences. As a practicing pharmacist I spent the first decade of my career working within this regulatory framework without ever stepping back to question why we regulate some products differently. I started reading, took the red pill, and here I am today.

As a Canadian, one of perspectives I hope that I can bring to the blog is the opportunity to compare how different countries address similar health challenges. While the FDA and Health Canada share similar drug approval processes, they differ dramatically in their approach to homeopathy.  The American Dietary Supplement Health and Education Act of 1994 (DSHEA) is an amendment to the U.S. Federal Food, Drug and Cosmetic Act that establishes a regulatory framework for dietary supplements. Given the criticism of DSHEA that is regularly dished out by SBM bloggers, I assumed that it also applied to homeopathy. I was wrong. The National Center for Complementary and Alternative Medicine (NCCAM) points out,

Homeopathic remedies are regulated as drugs under the Federal Food, Drug and Cosmetic Act (FDCA). However, under current Agency policy, FDA does not evaluate the remedies for safety or effectiveness. FDA enforcement policies for homeopathic drugs are described in FDA’s Compliance Policy Guide entitled Conditions Under Which Homeopathic Drugs May be Marketed (CPG 7132.15).

FDA allows homeopathic remedies that meet certain conditions to be marketed without agency preapproval. For example, homeopathic remedies must contain active ingredients that are listed in the Homeopathic Pharmacopeia of the United States (HPUS). The HPUS lists active ingredients that may be legally included in homeopathic products and standards for strength, quality, and purity of that ingredient. In addition, the FDA requires that the label on the product, outer container, or accompanying leaflet include at least one major indication (i.e., medical problem to be treated), a list of ingredients, the number of times the active ingredient was diluted, and directions for use. If a homeopathic remedy claims to treat a serious disease such as cancer, it must be sold by prescription. Only products for minor health problems, like a cold or headache, which go away on their own, can be sold without a prescription.

What NCCAM doesn’t mention is that homeopathy is an elaborate placebo system, where the “remedies” lack active ingredients. As would be expected with inert products, clinical trials confirm what basic science predicts: homeopathy’s effects are placebo effects. Yet these placebos, because they’re labelled “homeopathy” are regulated as drugs.  Amazingly, the the regulations delineate some homeopathy products as “prescription” and some as “non-prescription” based on what they’re being used for — not based on what they contain. Which is odd, because homeopathic remedies are chemically and therapeutically indistinguishably – they are inert.

Nonsensical? Yes. But that’s homeopathy.  To the FDA’s credit, they don’t waste resources reviewing products before they’re sold, and they explicitly don’t vouch for safety and effectiveness. Now let me introduce you to Health Canada’s Natural Health Products Directorate.

The Natural Health Product regulations, under Canada’s Food and Drugs Act, regulate homeopathic products as well as many of the products Americans regulate under DSHEA: nutritional supplements, probiotics, traditional Chinese medicine, vitamins, and herbal remedies. They are a deliberate shadow of the regulations that govern drug products — requiring some manufacturing quality and safety standards, while effectively removing the standards for product efficacy claims. Yet Health Canada insists that this doesn’t compromise quality, safety, or efficacy:

Through the Natural Health Products Directorate, Health Canada ensures that all Canadians have ready access to natural health products that are safe, effective and of high quality, while respecting freedom of choice and philosophical and cultural diversity.

The consequence? Regulation of the absurd. Health Canada reviews every remedy, and explicitly attests their safety and effectiveness. In Canada you can purchase Health Canada approved (Search each product by number here):

  • homeopathic sea water — DIN-HM 80017767
  • homeopathic insulin — DIN-HM 80016480
  • homeopathic granite — DIN-HM 80012752
  • homeopathic roasted sponge “Spongia Tosta” — DIN-HM 80011377
  • homeopathic chloroform DIN-HM 80010524
  • homeopathic table salt DIN-HM 80005389

There are hundreds more, including more well known products like Oscillococcinum and Traumeel, all deemed safe and effective.

It’s easy to laugh at the irony of homeopathic water, and the while the sale of these products is certainly unethical, when used for self-limiting conditions, the risk of harm may be slight. But a framework that gives even a veneer of credibility to sugar pills increases the perception that homeopathy has legitimate medical uses. We’ve seen this worldwide with homeopaths descending on Haiti or treating HIV in Africa, illustrating that proponents lack any insight into the lack of objective effects. More recently, the government of Madhya Pradesh, a state in India, announced a plan to use homeopathy to prevent malaria outbreaks. When homeopathy is used as a substitute for real medical treatments, the risk of harms are real, not theoretical. So I was concerned to to see the following in the Calgary Herald:

A Calgary business that aims to bring traditional homeopathic remedies to the mainstream public has received Health Canada approval for its first locally developed product. Mozi-Q is a natural mosquito repellent created by Calgary-based Xerion Dispensary. The product, made from a plant-derived substance called staphysagria, is taken orally and is advertised not only as a bug repellent, but as a product that will also lessen the stinging and itching associated with insect bites.

which also noted

All natural health products — including homeopathic remedies — sold in Canada are subject to the Natural Health Products Regulations, which came into force on Jan. 1, 2004. Only after Health Canada has assessed a product and decided it is safe, effective and of high quality, will a product be approved.

Effective. There it is. Yes, homeopathic insect repellent, approved by Health Canada with licence number 80031902, with the following “Recommended Use or Purpose”:

Homeopathic rememdy [sic] used for reducing the severity and frequency of insect bites.

And what’s in this product? Like most homeopathy, the labeling obscures the actual lack of ingredients. I converted the homeopathic labeling to English, and looked for evidence to support any of the ingredients – diluted or otherwise.

  • “cedron 4C:” This is Simaruba Ferroginea, commonly called Rattlesnake Bean in a 10−8 dilution (i.e., 0.000001%) — This product is related to the pinto bean. It is likely nontoxic, especially at this dilution.
  • “grindelia 6C”: Grindelia Robusta or Gumweed in a 10−12 dilution (i.e., 0.0000000001%) — This ingredient is considered “Possibly Safe” at non-homeopathic doses by the Natural Medicines Comprehensive Database
  • “ledum palustre 3X” : Marsh Tea in a 10−3 dilution (i.e., 0.1%) — This ingredient is considered “Likely Unsafe” at non-homeopathic doses by the Natural Medicines Comprehensive Database, causing kidney and urinary tract damage as well as central nervous system excitation.
  • “staphysagria 4X”: Delphinium staphisagria or Stavesacre in  10−4 dilution  (i.e., 0.01%) — This ingredient is considered “Likely Unsafe” at non-homeopathic doses by the Natural Medicines Comprehensive Database, as it is poisonous.
  • “urtica urens 6X” : Stinging nettle in a 10−6  dilution (i.e., 0.0001%) — This ingredient is considered “Possibly Safe” at non-homeopathic doses by the Natural Medicines Comprehensive Database.

Interestingly, some of the ingredients aren’t diluted past the “12C” level, the point at which Avogadro’s constant establishes that there isn’t likely to be a single molecule of the original ingredient. The 3X dilution of Marsh Tea is only a 1:1000 dilution, which depending on the original preparation, could deliver detectable traces of the source plant. Should we be concerned? The amount is so minute that it’s unlikely to have any meaningful effects, toxic or otherwise. But does it work? Not surprisingly there is no published evidence suggesting that any component of Mozi-Q, either alone or in combination, have any effect on either reducing the frequency of insect bites” or “reducing the severity of insect bites”. The manufacturer states the following:

Has it been studied?
In the ’60s a homeopath by the name of HR. Trexler studied Staphysagria for its effectiveness at preventing mosquito bites. In a study of 421 subjects over a 4 year period, he found this remedy to be 90% effective.

Tried and True!
We have tested this remedy in our clinic over four mosquito seasons and found the response from the public confirmatory of Trexler’s findings.

And that’s the sum total of the evidence — which appeared to be adequate for Health Canada, who granted the “safe and effective” imprimatur of legitimacy. A published report from Trexler does date back to 1965, and it’s not available. There are no other published reports with the product. I did find Trexler’s US patent registration from 1956 claiming that staphsagria is an effective insect repellent. No evidence of a formal evaluation is described. A patent, of course, doesn’t establish efficacy. Given the totality of evidence, has failed to show that homeopathy has any meaningful clinical effects, I am skeptical that a homeopath identified an effective homeopathic oral insect repellent in 1956, and subjected it to a rigorous evaluation in the 1960’s. In any case, it would be easy to prove if it does work – it could be evaluated like every other insect repellent on the market.

How Real Insect Repellents work

For many of us, insect bites are an occasional annoyance that we can largely avoid. Yet insects can transmit over 100 diseases, including malaria, West Nile virus, yellow fever, Dengue fever, Lyme disease and even plague. Malaria alone kills 1.2 million people, mainly African children, annually. And now that we have West Nile and Lyme disease throughout North America, there is a bigger impetus to minimize bites. Given the importance of repelling insects effectively, validated methods have been created to test new products.

While it’s not definitively established what attracts insects to bite, carbon dioxide and lactic acid from our skin and breath seem to act as attractants. In light of this, it’s not surprising that no oral product has ever been demonstrated to effectively work as an insect repellent. What does work, beyond physical barriers, are chemical products that we apply to our skin.  The most common ingredient in repellents is N, N- diethyl-3-methylbenzamide, more commonly known as DEET, although there are several other chemicals that have been approved for use in consumer products.

How do you know if an insect repellent works? You offer your forearm up as a meal. Consumer Reports illustrates the testing nicely. The US Environmental Protection Agency specifies these testing requirements in detail. Its approval outlines the duration of effectiveness as well as detailed descriptions of the efficacy and safety evaluations. In Canada, similar regulation rests with the Pest Management Regulatory Agency. When I asked the PMRA by email how a homeopathic remedy could be possibly be approved as an insect repellent, they replied with the following:

Please be advised that, according to the Pest Control Products Regulations (PCPR), pest control products that are used for the control of arthropods on or in humans or animals can be exempted from the Pest Control Products Act (PCPA), and made subject to the Food and Drugs Act (FDA), if the control product is to be administered directly and not by topical application. If the action of the product is not due to the simple presence of the active ingredient on the skin (the intent of topical application under the PCPA) but rather that the active ingredient has to be absorbed first before it can exert its effect, this is not considered to be a topical mode of action. This would be the case for mosquito repellent patch products. Even though the patch is to be applied to the surface of the skin, the PMRA does not register any pesticide that’s to be taken orally. Based on this systemic mode of action, as per a previous agreement between PMRA and Health Products and Food Branch (HPFB), the type of product you describe in your email would fall under the jurisdiction of HPFB.

Is there a facepalm emoticon? There is no “systemic mode of action” that has been demonstrated for homeopathy. There is no evidence that any oral products are effective as insect repellents. In the US, a product like Mozi-Q which lacks evidence of efficacy would not likely be permitted, (homeopathy or not) as there is a  federal regulation on oral insect repellents in place, which notes:

Labeling claims for OTC orally administered insect repellent drug products are either false, misleading, or unsupported by scientific data.

Any OTC drug product that is labeled, represented, or promoted for oral use as an insect repellent is regarded as a new drug within the meaning of section 201(p) of the Federal Food, Drug and Cosmetic Act for which an approved new drug application under section 505 of the act and part 314 of this chapter is required for marketing. In the absence of an approved new drug application, such product is also misbranded under section 502 of the act.

Clinical investigations designed to obtain evidence that any drug product labeled, represented, or promoted OTC for oral use as an insect repellent is safe and effective for the purpose intended must comply with the requirements and procedures governing the use of investigational new drugs set forth in part 312 of this chapter.

Yet these products are being deliberately exempted from testing in Canada, and Health Canada is approving them in the absence of any good evidence.


When a regulator clears away scientific barriers to product approvals, we should not be surprised by what emerges.  Homeopathic insect repellent that is deemed “safe and effective” illustrates the consequences of regulating nonsense. Consumers who rely on regulators to test and approve products don’t care how a product is licensed – they want assurance that it works. Because while insect bites can be a nuisance, they can also be deadly. Who will be responsible if a consumer contracts a insect-borne disease if they use homeopathy instead of proven insect repellents: The manufacturer, or the regulator? In the absence of effective regulation, the science in this case is very clear: if you want to reduce your risk of insect bites and their consequences, use real insect repellents — not homeopathy.




Posted by Scott Gavura