This is the biggest practical difference between the two drugs. Foundayo’s dose isn’t a forum consensus. It’s printed in the prescribing information.
Foundayo’s actual label
Step Daily dose Minimum time before stepping up
Start 0.8 mg 30 days
Step 2 2.5 mg 30 days
Step 3 5.5 mg 30 days
Maintenance 9 mg, 14.5 mg, or 17.2 mg Each increase at least 30 days apart
Note: trial doses and label doses don’t match
The trials used capsules at 6, 12, and 36 mg. The approved product is a different tablet formulation, and the ACHIEVE-4 paper states that the 36 mg capsule is equivalent to the 17.2 mg tablet. So “17.2 mg” on your prescription is the trials’ top dose, not half of it.
Two label rules
Take one tablet a day, swallowed whole.
If you miss seven or more doses in a row, restart the titration at a lower dose rather than jumping straight back in.
Retatrutide: trial schedules and gray-market practice
In trials, retatrutide started at 2 mg once weekly and stepped up every four weeks to 4, 9, or 12 mg. Community protocols reportedly start lower, around 0.5 to 1 mg weekly, and many people describe stopping at 4 to 8 mg.
No validated retatrutide protocol exists outside a clinical trial. What people do is a description, not a recommendation.
The reconstitution arithmetic is the same as any lyophilized peptide: concentration equals vial strength divided by the volume of bacteriostatic water you add.
Vial BAC water added Concentration 2 mg dose on a U-100 syringe
10 mg 2 mL 5 mg/mL 0.4 mL = 40 units
20 mg 2 mL 10 mg/mL 0.2 mL = 20 units
30 mg 3 mL 10 mg/mL 0.2 mL = 20 units
Conclusion
Foundayo’s dose has clear legal and medical backing; Retatrutide’s dose is a gray-market exploration by the community. The gap between the two is much more than the numbers themselves.