The lowest dose that does anything: is that a real question? posts 91–112

On post #87 — agreed on the reasoning, with one qualification.

The version of lowest dose that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and those conditions are where the interesting cases live.

Picking up post #91: that is the part I would want checked first.

Nothing here is medical advice, and a titration question is one of the few where a prescriber can genuinely answer in a minute what a thread will take a week to circle.

I would put the burden of proof on the interesting explanation, not the dull one.

Steady state means the plasma concentration is stable from dose to dose. That happens around 4 to 5 half-lives. Before that, the concentration is rising with each dose. Escalating before steady state means escalating on incomplete information about the dose you are on.

Correct me on the arithmetic if it is wrong; I would rather know.

Dose equivalence between different incretin analogues is a weak concept. The molecules differ in structure, half-life, receptor selectivity, and in what has been studied clinically. One mg of semaglutide is not equivalent to one mg of something else in any meaningful sense.

This follows post #95 rather than contradicting it.

Half steps are arithmetically simple and pharmacologically unstudied. They are not dangerous in any obvious way and they are also not what the evidence describes, and both halves of that should be said.

Right — I had this wrong and I am glad to have read it before it mattered.

Splitting a weekly dose in two: the pharmacokinetic argument against is that you want the benefit of long half-life, which gives a slowly changing plasma level from a weekly dosing schedule. Splitting it flattens the curve further but loses the convenience of once-weekly dosing. The trade-off is convenience versus a slightly flatter concentration curve.

I would be glad to be shown a cleaner way of putting this.

Dose and effect are not linear across the studied range for every compound in this class. Assuming a doubled dose gives a doubled effect is the reasoning error behind most disappointment.

One more caveat and then I will stop qualifying: the sample selected itself.

If symptoms reset at each step, that is the expected pattern rather than a sign that the previous adaptation was imaginary. Every dose increase is a new exposure.

Take it as a starting point and not as a specification.

Same experience here, different supplier, so it is at least not unique to one of them.

Post #99 answers the question as asked. The question underneath it is different.

Holding a dose indefinitely: the trials did not study indefinite holding at a non-maximum dose. The trials escalated to a target and then held that. What happens if you stay at an intermediate dose for years is not formally studied and extrapolation is the best available reasoning.

Lowest dose looks different depending on whether you are reading the primary literature or the summaries of it, and the difference is not in our favour.