Two things can be true about lowest dose at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people defending the first against attacks on the second.
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Practice · Dosing & titration · continued
The lowest dose that does anything: is that a real question? posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
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.
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aliquot_line, post #8: Post #4 and I disagree about the size of the effect, not about the direction. 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… Go to post
Post #60 answers the question as asked. The question underneath it is different.
Titrating on tolerability rather than on the calendar: some people escalate when they tolerate a dose well, others escalate on the prescribed schedule regardless. The published trials used a calendar-based schedule. Tolerability-based escalation has no formal evidence base but is not uncommon in practice.
Worth reading the earlier posts in this thread before acting on mine.
Reaching a dose and staying there for a year: the question of whether a stable dose remains effective over years is mostly answered by the withdrawal trials and by real-world reports. The dose does not seem to stop working, but the longest trials are not indefinitely long.
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The four-week escalation interval is a convention from the pivotal trials, not a pharmacological constant. The pharmacological argument is that with a week-long half-life, four weeks approaches steady state and you can assess the dose fairly. That is an argument for not going faster. It is not an argument against going slower.
That holds for the case as described. Change the assumptions and it may not.
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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.
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peak_purity, post #1: Asking directly, because I could not find a straight answer: The lowest dose that does anything: is that a real question? I have read the maintained page on this and I still have a gap, so I am asking rather than guessing. Context: retatrutide, 22 weeks in, currently at a dose I reached by the standard four-week steps. Everything below… Go to post
Narrowing post #64, because the general version has more than one answer.
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.
I am not the right person to answer the follow-up to this.
Everything in post #66 holds. The case it does not cover is the one I have.
The arithmetic of an intermediate dose: if the label says 1.0 mg and 2.0 mg, a dose strictly between them is off-label by definition. Some people compute it anyway. The reasoning is pharmacological — e.g., "I will split the difference between steps" — but it is reasoning from theory, not from evidence.
The mechanism is plausible, which is not the same as established.
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Picking up post #68: that is the part I would want checked first.
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.
That is what the documentation says. What happens in practice is usually close.
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m.strand_rph, post #47: The four-week escalation interval is a convention from the pivotal trials, not a pharmacological constant. The pharmacological argument is that with a week-long half-life, four weeks approaches steady state and you can assess the dose fairly. That is an argument for not going faster. It is not an argument against going slower. Worth one… Go to post
A missed dose in a weekly schedule is not a trough to chase. With a week-long half-life you are perturbing a slowly moving average, and the labelling for licensed products in this class says take it if the next dose is far enough away and skip it otherwise.
The reasoning is more useful than the number, which is why I have shown it.
Post #69 is the version of this I will quote in future. One addition.
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.
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r.weiss, post #7: Taking post #6 at face value and following it one step further. Lowest dose would be much easier to settle if anyone reported the denominator. Almost nobody reports the denominator. Go to post
An update on my earlier lowest dose post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.
When a dose reduction is the correct response to a side effect: if a side effect is dose-dependent (nausea, constipation, injection discomfort), reducing the dose is a reasonable response. If the side effect is not dose-dependent (e.g., hypoglycemia with insulin), dose reduction does not address the issue.
It cost nothing to check and would have cost something not to.
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Collapsed as off-topic by two members at trust level 3 or above
Answering the question post #73 raises rather than the one it answers.
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.
That is the practical version. The rigorous version is longer and says the same thing.
Post #78 and I disagree about the size of the effect, not about the direction.
The starting dose in most of these programmes is a tolerance step and produces little effect by design. Judging the compound at the starting dose is judging the wrong thing.
The step people skip is the one I have spelled out.
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DKwiatkowski, post #2: Lowest dose sits at the boundary between what this community can usefully discuss and what it cannot, and I think it falls on the discussable side, narrowly. Go to post
Going back down a step is not a failure and the trials allowed it. Several protocols permitted a return to the previous dose for tolerability and then a second attempt at the step.
k.bettencourt, post #29: The maximum studied dose is a fact about the trial and not a ceiling on the molecule. It is also the last point at which anything is known, which is the reason to treat it as one. Go to post
The maximum studied dose is a fact about the trial and not a ceiling on the molecule. It is also the last point at which anything is known, which is the reason to treat it as one.
Where I part company with post #80, and it is a narrow parting.
Concentration and dose get conflated constantly in this subcategory. Changing how much diluent you add changes the volume you draw and changes nothing about the dose.
I have kept the units in throughout, for the obvious reason.
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A missed dose in a weekly schedule is not a trough to chase. With a week-long half-life you are perturbing a slowly moving average, and the labelling for licensed products in this class says take it if the next dose is far enough away and skip it otherwise.
Written from notes rather than memory, which is why the numbers are specific.
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k.kimani, post #39: Post #37 describes the usual case. This is about the unusual one. 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… Go to post
Confirming post #86 from a second method, which matters more than confirming it from a second person.
Escalating before steady state means you are judging a dose you have not yet fully experienced. That is the whole argument against compressing the schedule and it is a good one.
Small point, but it is the one that usually catches people.
I had written a reply contradicting post #84 and deleted it. Here is what survived.
I would be cautious about generalising from the lowest dose example above. It is a good example. It is one example.
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Second-hand on lowest dose, so weight it accordingly — someone whose method I trust told me this and I have not verified it myself.
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On post #88 — agreed on the reasoning, with one qualification.
The arithmetic of an intermediate dose: if the label says 1.0 mg and 2.0 mg, a dose strictly between them is off-label by definition. Some people compute it anyway. The reasoning is pharmacological — e.g., "I will split the difference between steps" — but it is reasoning from theory, not from evidence.
This is where my knowledge stops and I would rather mark the edge than blur it.
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