Dosing Guide — 2026-10-28
Reta 20mg is the size experienced researchers reach for once they know they'll run past the opening titration weeks. The protocol is identical to the 10mg vial — the only difference is that one 20mg vial holds twice the peptide, which makes it the more economical choice per milligram for any protocol that settles at a steady weekly dose. This guide covers the reconstitution math, the weekly schedule, and how long a vial realistically lasts. For laboratory research use only.
You can find current pricing and the batch COA on the Reta 20mg page, and the exact numbers are mirrored in the Reta 20mg dosing guide. Both are linked again below at the points where they matter.
Reta is a triple agonist acting on the GP-1, GIP, and glucagon receptor systems — the 20mg vial is simply a larger fill of the same peptide, not a different product. Everything you've read about the 10mg protocol applies here unchanged; you just reconstitute with more water so each unit on the syringe stays the same size.
Reta is dosed once weekly, titrated up from a low starting point:
| Week | Dose | Units (U-100 syringe) |
| Week 1 | 2 mg | 20 units |
| Week 2 | 3 mg | 30 units |
| Week 3 onward | 4 mg | 40 units |
Four milligrams is the standard target. Maintenance after reaching a goal typically drops to 1–2 mg (10–20 units) weekly. If results plateau after 6–8 weeks at 4 mg, step up to 6 mg then 8 mg, one increment at a time and never sooner than two months at the lower dose.
Add exactly 2 mL of bacteriostatic water to the 20 mg vial. The extra water keeps the concentration — and therefore your syringe units — identical to the 10mg vial:
So a 2 mg dose is still 20 units and a 4 mg dose is still 40 units — the unit markings mean exactly what they did on the smaller vial. Inject the water down the vial wall, swirl gently, and refrigerate. You'll need bacteriostatic water for this; the how to reconstitute Reta 20mg guide covers the technique in detail.
A 20mg vial holds 20 mg total — roughly double the 10mg vial at every dose:
| Weekly dose | Doses per vial |
| 2 mg | 10 weeks |
| 3 mg | ~6.5 weeks |
| 4 mg | 5 weeks |
That's the appeal: a single 20mg vial can carry a full titration plus a steady 4 mg phase without reordering mid-protocol. The Reta 20mg vs two 10mg vials comparison shows the per-milligram savings versus buying two smaller vials.
Inject subcutaneously once weekly, rotating sites. As with any Reta protocol, nausea and fatigue are most likely in the early weeks and after each step-up — hold the dose an extra week if side effects are intense rather than pushing through. Keep protein intake high and maintain resistance training to protect lean mass during rapid appetite suppression.
Refrigerate the dry powder before mixing. After reconstitution, store at 2–8°C and use within about four weeks. Skip freeze-thaw cycles.
Because the 20mg vial is a longer commitment, consistent potency across the whole vial matters even more. Every Reta 20mg vial from Platinum Biolabs ships with a batch-matched COA at 99%+ HPLC purity, handled from a US facility — so your week-10 dose is as accurate as your week-1 dose. Code PLATINUM25 takes 25% off at checkout. Running a shorter or trial protocol first? The Reta 10mg vial is the lower-commitment starting point.
Disclaimer: All information presented in this article is for educational and informational purposes only. Platinum Biolabs does not promote or endorse the use of peptides for human consumption. All products sold by Platinum Biolabs are intended strictly for laboratory and research use only. Consult a qualified healthcare professional before making any health-related decisions.