31G is the ultra-fine end of the practical needle-gauge range — what GLP-1 pens (Mounjaro, Ozempic, Wegovy) ship with, and what most people switch to when they have been on weekly injections long enough to value comfort over draw-up speed. This site collects what we have learned about 31-gauge pen needles and syringes from running an EU supplier: what 4 mm vs 5 mm vs 6 mm actually changes, how to spot a counterfeit pen needle, and the rotation pattern that keeps a year on a GLP-1 from leaving your skin like a pin cushion.
We do not sell anything here. The articles below are the notes we send first-time GLP-1 buyers when they email asking which pen needle to order. If you decide a 31G is what you want, you can pick up a sterile pack at injectkit.com — but read the technique pages first. The needle is rarely the bottleneck; the angle, the speed and the spot are.
For thicker oils where 31G will clog or bend, see our sister site 29-g.com. For the all-rounder gauge, see 30-g.com.
Practical, source-cited writing on 31G pen needles and syringes — from the team that ships them across the EU.
Subcutaneous injection
The three subcutaneous injection sites — abdomen, outer thigh, upper arm — compared on absorption speed, comfort, ease of self-injection, and lipohypertrophy risk.…
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Glp 1
Mounjaro, Wegovy and Ozempic needle and syringe sizes — practical UK guidance on gauge, length and travel kit options for GLP-1 self-injection.
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Glp 1
4 mm is the modern default for GLP-1 self-injection. 5 mm is fine. 6 mm and 8 mm are mostly leftover diabetes-era stock. Here's what the FITTER consensus and EMA…
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Mounjaro
Step-by-step Mounjaro KwikPen injection protocol from the Eli Lilly user manual, with the bits where first-time UK users actually get stuck.
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Mounjaro
What pen needles fit the Mounjaro KwikPen, what UK pharmacies actually charge, and what Lilly's instructions require. 4 mm × 31G or 32G is the modern default.
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Glp 1
Lipohypertrophy is rare on weekly GLP-1 injection but not zero. Here's a simple 4-week abdomen-and-thigh rotation pattern, with the FITTER guidance behind it.
Read articleIf you decide 31G is the right gauge for your routine, our sister shop sends sterile, individually-blistered pen needles and syringes from Spain across the EU and UK. Free shipping over €50.
Imogen Whitcombe
Editor · 31-g.com
31-g.com is the content arm of InjectKit, an EU sterile-syringe supplier operated by meeco Servicios Globales S.L. (CIF B42774703, Alicante, Spain). Articles are written by people who handle these syringes daily — and reviewed against the manufacturer's IFU before publication.
If you spot something wrong in an article, email [email protected] and a human will read it. See our editorial policy for the full version.
Tudo o que precisa de saber antes de encomendar.
O calibre 31 é a agulha de uso estéril mais fina disponível comercialmente — ideal para uso pessoal com mínimo desconforto. Se a sua prescrição indicar outro calibre, siga o conselho do seu médico. Para 29G ou 30G, visite 29-g.com ou 30-g.com.
As encomendas são enviadas desde Espanha e chegam em 2-3 dias úteis à maioria dos países UE. O número de rastreio chega por email assim que o pacote sai.
Envelope almofadado neutro. O remetente aparece como meeco SL, sem nomes de produtos, termos clínicos ou marcas visíveis no exterior. Só você sabe o que está dentro.
Embalagens fechadas e seladas podem ser devolvidas em 14 dias após a entrega para reembolso total. Por motivos de higiene não aceitamos devoluções de embalagens abertas. Escreva para [email protected] para iniciar uma devolução.
Sim. As nossas seringas são suprimentos com certificação de qualidade, em conformidade com o Regulamento UE de Dispositivos Médicos (RDM 2017/745). Esterilizadas com óxido de etileno e embaladas individualmente. Cada lote é rastreável até ao fabricante.
Sim. Enviamos para todos os países da UE, Suíça, Noruega e Reino Unido. Os prazos fora da UE podem ser ligeiramente mais longos (3–7 dias úteis) e podem aplicar-se direitos aduaneiros.