What a V4 Pen Actually Is
A V4 peptide pen is a reusable, cartridge-fed injector pen from the generation between the V3 and the V5: metal body, 1–60 unit dial in 1-unit clicks (1 unit = 0.01ml), the standard replaceable 3ml glass cartridge, and the universal pen-needle thread. If that sounds exactly like a V3 — that's the point.
- Dial range
- 1–60 units — identical to the V3
- Cartridge
- 3ml glass, standard format
- Needle fitting
- Standard pen-needle thread
- Needle mount
- Fixed (no V5-style retraction)
- Body
- Metal, revised styling vs V3
- Functional gain over V3
- None of substance
Why Most UK Ranges Skipped It
The V4 is a manufacturing and styling revision, not a functional upgrade. It dials the same 60 units as the V3, loads the same cartridge, and fits the same needles — so for UK suppliers already stocking the V3, it offered customers nothing new to buy. The generation that did change something is the V5, with its 80-unit dial and retracting needle, and most ranges — including ours — stepped directly from V3 to V5 for exactly that reason.
That said, the V4 is a real, working pen, and a small number of UK sellers do stock it, typically positioned at a budget price. There is nothing wrong with one; it just doesn't add anything.
V4 in the Lineage
| Version | Dial | Needle | Verdict |
|---|---|---|---|
| V3 | 1–60 units | Fixed mount | The UK standard — proven, widest availability, best value |
| V4 | 1–60 units | Fixed mount | A styling revision of the V3 spec — functionally the same pen |
| V5 | 1–80 units | Retracting | The actual next generation — both headline upgrades live here |
The full version-by-version history, V1 and V2 included, is in the peptide pen versions guide. Dedicated references: the V3 explained and the V5 generation.
Offered a V4? Check These First
- Price against a V3: a V4 should cost no more than a V3 — if it's priced above one, you're paying extra for a styling change.
- Cartridge format: confirm it takes the standard 3ml glass cartridge, so refills are never a hunt.
- Needle thread: standard pen-needle fitting — 31G/32G needles from any supplier should fit.
- What it adds: ask what the V4 gives you that a V3 doesn't. If the answer is a colour, that's the honest answer.
- UK stock and consumables: same rule as any pen — UK-held stock, and a supplier who also sells the cartridges, needles and cases.
What to Buy Instead
For the same 60-unit dial at the best price, with cartridges, needles and cases on the same shelf: the V3. For the genuine upgrade — 80 units and a retracting needle: the V5. Both UK-held stock, same-working-day Royal Mail dispatch, multi-buy discounts applied automatically.
V3 Pen — price & colours V5 Pen — the upgradeAll hardware is supplied for laboratory and research use. Nothing on this page is medical advice, and no product here is a medicine or sold for administration to people.
Frequently Asked Questions
What is a V4 peptide pen?
A reusable cartridge-fed injector pen from the generation between V3 and V5: metal body, 1–60 unit dial, standard 3ml cartridge and needles. Functionally, it matches the V3's specification.
V4 vs V3 — what's the difference?
On paper, very little. Same dial range, same cartridge, same needles. The V4 is a cosmetic and manufacturing revision, which is why most UK ranges never adopted it.
V4 vs V5 — what's the difference?
The V5 is the real upgrade: 1–80 unit dial and a retracting needle. The V4 has neither — it keeps the V3's 60-unit dial and fixed needle mount.
Do standard cartridges and needles fit a V4?
Yes — the standard 3ml glass cartridge and standard screw-thread pen needles fit V4 pens, the same as every other generation.
Should I buy a V4 pen?
Nothing wrong with one — but it adds nothing over a cheaper V3, and lacks both of the V5's upgrades. Most buyers are better served by a V3 for value or a V5 for the step up.