Tirzepatide 20mg vs 30mg: Which Vial Size Should You Buy? (UK 2026)
Research-grade tirzepatide is most commonly sold in two vial sizes: 20mg and 30mg. The peptide inside is identical. What changes is how much is in each vial, and that affects your cost per milligram, how concentrated your solution is after reconstitution, and how long a vial lasts once it is in solution. This guide covers each factor so you can pick the right tirzepatide vial for your lab.
Quick answer: the 30mg vial is better value per milligram (£2.50/mg vs £2.75/mg) and only costs £20 more than the 20mg. The 20mg suits shorter projects or slower use. For ongoing work, the 30mg 3-pack brings the price down to £2.11 per mg.
Tirzepatide Vial Sizes Compared
| Option | Price | Cost per mg | Best for |
|---|---|---|---|
| Tirzepatide 20mg | £54.99 | £2.75 | Shorter projects, slower use |
| Tirzepatide 30mg | £74.99 | £2.50 | Best single-vial value |
| Tirzepatide 30mg 3-Pack | £189.99 | £2.11 | Ongoing research |
| Tirzepatide + MOTS-C Research Duo | £79.99 | n/a | Combined metabolic research |
All vials are ≥99% HPLC purity with a batch-specific Certificate of Analysis. See every certificate on our Lab Results page.
1. Cost per Milligram
The 30mg vial holds 50% more peptide than the 20mg for only £20 more, which takes the cost from £2.75 to £2.50 per mg. If your project needs more than 20mg in total, a single 30mg vial is usually the better buy. If you need 40mg or more, compare two 20mg vials (£109.98, £2.75/mg) with the 3-pack below, which is far cheaper per milligram.
The 30mg 3-pack is the lowest price per milligram at £2.11, saving £34.98 on buying three vials separately, and it qualifies for free next-day delivery.
2. Concentration After Reconstitution
Tirzepatide is supplied as a lyophilised (freeze-dried) powder and is reconstituted with bacteriostatic water. The final concentration is the amount of peptide divided by the volume of water added:
| Vial | + 1ml water | + 2ml water | + 3ml water |
|---|---|---|---|
| 20mg | 20mg/ml | 10mg/ml | 6.67mg/ml |
| 30mg | 30mg/ml | 15mg/ml | 10mg/ml |
A 30mg vial gives a stronger solution for the same volume of water, which helps when your protocol calls for small, precise volumes. If you prefer a round 10mg/ml, add 2ml to a 20mg vial or 3ml to a 30mg vial. Our free Peptide Reconstitution Calculator works out concentration and volume for any combination, and How to Reconstitute Research Peptides explains the method step by step.
3. Storage and How Fast You’ll Use It
Unopened lyophilised vials are stable for a long time at 2–8°C. Once reconstituted with bacteriostatic water, the solution should be kept refrigerated and is generally used within about four weeks.
- Using it slowly? The 20mg vial means less material sitting in solution, so less risk of it passing the four-week mark.
- Using it steadily? The 30mg vial gives better value and fewer vials to prepare.
- Running a longer project? The 3-pack keeps two vials sealed as stable powder until you need them.
More detail in Bacteriostatic Water: How Much to Use and How Long It Lasts.
4. What Else You’ll Need
Each vial needs bacteriostatic water, syringes and alcohol swabs. The Starter Accessory Pack covers all of it in one order. Browse all bundles and value packs for multi-vial savings.
Which Size Should You Choose?
- Choose 20mg for the lowest upfront cost, a shorter project, or slower use where you want less material in solution.
- Choose 30mg for the best value single vial at £2.50 per mg.
- Choose the 30mg 3-pack for ongoing research at £2.11 per mg with free next-day delivery.
View Tirzepatide 20mg and 30mg →
Frequently Asked Questions
Is tirzepatide 20mg different from tirzepatide 30mg?
No. It is the same peptide from the same tested batch. Only the amount per vial changes.
Which tirzepatide vial is the best value?
The 30mg vial is the best single vial at £2.50 per mg. The 30mg 3-pack is cheaper still at £2.11 per mg.
How much bacteriostatic water do I add to a tirzepatide 20mg vial?
It depends on the concentration you want. Adding 2ml to a 20mg vial gives 10mg/ml; adding 1ml gives 20mg/ml. Use the Peptide Calculator to work out any combination.
How long does reconstituted tirzepatide last?
Reconstituted with bacteriostatic water and kept at 2–8°C, it is generally used within about four weeks. Unopened vials last much longer in the fridge.
Where can I buy tirzepatide vials in the UK?
Revial Labs stocks research-grade tirzepatide 20mg and 30mg vials in the UK at ≥99% HPLC purity, dispatched by Royal Mail Tracked. See our Tirzepatide UK guide for how to choose a reliable supplier, and Tirzepatide vs Retatrutide if you are comparing compounds.
This article is provided for educational and informational purposes for laboratory research professionals. All Revial Labs compounds are supplied strictly for in vitro laboratory research use only and are not for human or veterinary use. Research-grade tirzepatide is not a medicine and is not a substitute for any prescription product.
