As a new contributor to Chemistry Blog, I’ve decided to ‘break myself in’ by tackling the somewhat controversial and thought-provoking topic of homeopathy. As I write, we find ourselves part way through ‘World Homeopathy Awareness Week’, so the subject is enjoying quite a high profile and twitter seems to be alive with discussion on the matter.

Before I go further, I feel I should declare myself to be a sceptic. I’m doubtful as to whether any other point of view on this subject would be published on Chemistry Blog –so that will come as no surprise. After completing my chemistry studies, I chose a career in the pharmaceutical industry –to make a difference. I also rely on daily medication to manage my own condition. I’m therefore very aware of the difference proven chemistry can make to the quality of people’s lives. The science of drug development is founded on proven facts; a great deal of money, effort, time and hard evidence is required for just one new drug to reach the market –I will return to this subject in a later article.

What are the principles of homeopathy?

Homeopathy is an alternative medicine, based on the principle of treating like with like. Patients are treated with highly dilute preparations believed to cause symptoms in a healthy person, similar to those being experienced in the patient. Commonly used dilutions are 10C and 30C.

To achieve a 30C dilution, the ‘active’ ingredient is diluted 1 part in 100 –and then a drop of this solution would be diluted to 1 part in 100 and so on for 30 repetitions. The resulting final solution would be 1 part active in 1 followed by 60 zeroes. To put this number in perspective; one molecule of ‘active’ in a volume the size of the entire observable universe would be 40C. Homeopaths claim a process called ‘succussion’, the act of striking the vessel containing the solution against an elastic surface 10 times at each stage of the dilution process, activates the ‘vital energy’ of the diluted substance and they talk, not in terms of dilution, but in terms of ‘dynamisation’ or ‘potentisation’.

As chemists we know there is a limit to any dilution that can be made without losing the original substance entirely. This limit is related to Avogadro’s number and in homeopathic terms roughly 1 part in 1024 –equivalent to a 12C preparation. A 30C preparation would require giving 2 billion doses per second to 6 billion people for 4 billion years to deliver a single molecule of the original material to any patient. It is worth pointing out here that homeopathy dates from a time predating the discovery of atoms and molecules, so it was a widely held belief that a substance could be diluted ‘ad infinitum’.

Homeopaths believe the more dilute a preparation is the more effective it is. They believe the diluent used (usually water) has a memory of the active molecule it once contained. My professional life as an analytical chemist would be a living nightmare if this were the case and carefully prepared diluents were ‘remembering’ the properties of the all the compounds they had contained. Just imagine what the HPLC chromatograms would look like! There would simply be no point in trying to keep the equipment free from contamination. The notion of ‘molecular memory’ is at best implausible; it suggests the shape of a molecule is more important than its chemistry. Putting reason aside for a moment and accepting that water has memory –how would it emulate the chemistry of that molecule? That very notion would require our current understanding of chemistry to be re-written and that understanding has provided us with thousands of medications which have been proven to be effective.

Clearly, if homeopathy achieves a successful clinical outcome, there is something else at work here. There is likely to be a significant ‘placebo effect’ and there is anecdotal evidence to support this idea. Also, the act of consulting the homeopath and the attention and sympathy the practitioner gives the patient –is believed to support the healing process. This, however, can be dangerous when the practitioner advises the patient against engaging with conventional medicine –this can, and has, resulted in tragic consequences.

As a complementary therapy, homeopathy appears to benefit some and as such it has its place in modern medicine. It isn’t sensible to use it as the only course of treatment for any condition, especially not a serious disease. The ‘science’ doesn’t stack up -it’s just sympathetic magic.