A frequent discussion I’ve seen (generally on twitter, and in some of the negative popular press articles about rapamycin) is around the possible side effects (or even the first effect approved… such as immune suppression).
I still see people disparaging rapamycin, or other potential longevity drugs, with lists or descriptions of terrible side effects, but with no mention at all about the dosing levels and dosing schedule (daily/weekly?) associated with those side effects, and not mentioning the frequency of these side effects.
We see this sometimes even here in our forums. So this is just a post for people to link to whenever someone does this… talks about side effects without talking about dosing or dose schedule.
Yes, the Dose Really Does Make the Poison
One thing that frustrates me in conversations about “harmful chemicals” on Skeptoid and elsewhere is when individuals display a complete lack of understanding of dosage. This comes in two forms.
The first form is the passive argument that completely omits"dosage" from their point entirely. I can never tell if someone overlooking dosage is being uninformed or dishonest; part of me wants to give the benefit of the doubt, but another part of me finds it hard to believe they’ve never encountered such a basic concept as dosage. The second is the active argument that “Dosage doesn’t matter” or “dosage is irrelevant”, which is often used to imply that some chemical or other isso badthat isalways should be avoided. Invariably this is directed at some chemical that millions of people ingest everyday without obvious harm.
Both of these arguments fall flat in the face of scrutiny. Dosage very much matters , because all chemicals are toxic . This is not a sweeping generalization; it’s just a basic fact of chemistry. Toxic is a word you hear people throwing around a lot without any actual sense of definition or context, i.e. “toxic chemicals”, but there is no such thing as a “non-toxic chemical”; everything is a chemical and all chemicals have a point where they become toxic to the human body.
The term for the dose at which a chemical becomes dangerous or deadly is toxicity . In chemistry they also refer to a chemical’s “lowest published toxic dose”, or Toxic Dose Low (TDL), the point at which a chemical will start to have adverse effects on the body. The point at which a chemical becomes toxic enough to kill is called its Lethal Dose Low (LDL). Every chemical has a TDL and a LDL, though the levels vary greatly from chemical to chemical.
Consider water, the most common and important ingredient in the things we consume. In debates about chemicals we skeptics love to bring up water (which irritates the toxic chemicals crowd to no end) because it’s an extreme and obvious illustration of the point: water, in large enough quantities, can kill. It has both a TDL and a LDL. And no, I’m not talking about drowning; I’m talking about water intoxication, which can kill you. And yet we drink it every single day.
Full article here:
