There are people on 20 mg of tirz who wouldn't start with 6 mg of reta, let alone 8 mg. Those doses would be week nine on a reta trial. Eight weeks is a long time for glucagon adjustments compared to zero adjustment.
And this thread is about (less conservative) transitioning (with "cross-titrating" in the title, essentially stacking), not swapping (stopping tirz completely and starting reta). The old-school swapping approach (when all of this was new), was to titrate down with tirz, then stop completely, before starting reta at a low starting dose. Obviously, some people did not like the conservative approach since it was almost ideal for them gaining weight.
Someone with previous high tolerance to tirz may or may not be fine with 6 mg of reta as a starting dose. We don't have the data to make any generalizations. But we do know that no one in the phase 3 reta trials hit at least 6 mg until the third month (4 mg, 6 mg, or 8 mg for the third month). Phase 2 for reta tried up to 4 mg as a starting dose, but they settled on 2 mg with phase 3 due to GI sides. But even if doing 4 mg, I wouldn't do it as a single dose, splitting instead.
Also, it's always safer for the first dose of any new kit to be a baby dose, especially if not third-party tested already.
In any case, there is no need to redline the glucagon engine in week one. And the half life of reta is slightly longer (6 days) than tirz (5 days). If were were talking about shorter-acting lira or orfo, then there would be less concern.
There are other effects as well unique to reta/glucagon on the liver, blood pressure, etc. Some reta-specific threads on sides:
So, after Reddit was mentioned in another thread, I popped over. YIKES! Anyways, one had mentioned getting light headed and passing out, along with a few others. This got me thinking, as I've had like 2 of slight light headed deals in the last week, nothing major and goes away quick. Now, we've...
glp1forum.com
My first 4 weeks were completely fine. Then during the last 2–2.5 weeks I’ve had two panic-attack–type episodes within a few days after my injection — racing heart, sudden anxiety, heavy “WTF is happening” feeling. The last one hit hard enough that I went to the VA and they had to give me Ativan...
glp1forum.com
At least at this forum, we don't see complaints about 22-day hiccups or projectile vomiting with tirz as we have seen with reta. Those who have been through it learned the hard way that reta can hit differently.
For
@BamaCrazy, professional medical intervention was of limited benefit for ongoing reta hiccups (after going from 8 mg to almost 12 mg of reta; titrating up while not taking test mg into account):
With
@bluefootedboobie, another case of reta hiccups, on 7 mg:
Tldr; Has anyone else experienced hiccup problems on reta? Does anyone have any advice? Long version: Beginning September 1st, I've had off-and-on severe hiccup problems. The first time it happened (9/1), I had moved from 5 mg to 7 mg of Reta weekly two weeks prior and was doing extremely...
glp1forum.com
Projectile vomiting with 1.5 mg of reta:
I was on 2mg tirz but it worked phenomenally. And then I found out about grey market and retatrutide. Decided to buy a reta kit from nexaph but not feeling the reta at all yet which I understand is normal. Should I stay on tirz 2mg while I titrate up?
glp1forum.com
Personally, I have ridden out some pretty bad GI sides while stacking or titrating up too aggressively. But, as before, I try to avoid anything that seems crazy as a way to avoid going to the ER, which I have avoided so far. I am only on 6 mg of tirz right now as a base for stacking, but all the GLP drugs hit strong for me at some mg when starting out, even the ones just affecting GLP-1 receptors (sema, lira, and orfo).
Some people on TG wanted to argue with me that starting with 12 mg of orfo (with a dose range of 1 mg to 36 mg) was fine for GLP veterans, even though the clinical trials settled on 1 mg. They were adamant since for theoretical reasons they didn't want to split the tablet into smaller pieces. But with reta (and the other injectables where you pick your dose), there is no such pressure to "go big or go home" when starting out.