Yes, the same 4-mm, 32-gauge pen needles used for NovoLog FlexPen can be used with the Toujeo pen.
Pen needles are universally compatible across insulin pen devices, regardless of insulin type or concentration, as long as they use the standard screw-thread attachment mechanism. Both NovoLog FlexPen and Toujeo pens accept the same pen needles.
Universal Needle Compatibility
The FDA-approved labeling for both products confirms this compatibility:
- NovoLog FlexPen is designed to be used with NovoFine, NovoFine Plus, or NovoTwist needles 1
- Toujeo Max SoloStar recommends needles from BD (such as BD Ultra-Fine), Ypsomed (such as Clickfine), or Owen Mumford (such as Unifine Pentips) that are 8 mm long or shorter 2
The key point is that pen needles attach via a universal screw-thread mechanism that fits all major insulin pen brands, including both Novo Nordisk pens (NovoLog) and Sanofi pens (Toujeo).
Optimal Needle Specifications
Current guidelines strongly recommend 4-mm, 32-gauge pen needles for all adults and children with diabetes, regardless of body mass index, insulin type, or pen device 3. This recommendation applies equally to:
- Rapid-acting insulins (like NovoLog/insulin aspart)
- Long-acting concentrated insulins (like Toujeo/insulin glargine U-300)
The 4-mm length is:
- Long enough to reliably deliver insulin to subcutaneous tissue
- Short enough to avoid intramuscular injection in virtually all patients
- Associated with less pain than longer needles 3
The 32-gauge width provides optimal balance between:
- Reduced injection pain (thinner is better)
- Adequate flow rate for insulin delivery
- Structural integrity to prevent needle bending or breakage 3
Important Caveats
Never use a syringe to withdraw insulin from Toujeo pens 2. Because Toujeo is U-300 (300 units/mL) versus the standard U-100 concentration, using a U-100 syringe would result in a threefold overdose—a potentially life-threatening error.
Always use a new needle for each injection 3, 1, 2. Needle reuse can cause:
- Blocked needles leading to underdosing or overdosing
- Increased infection risk
- Increased pain
- Lipohypertrophy (skin thickening/pitting at injection sites)
Injection Technique Considerations
When switching between different insulin types using the same needles:
- Inject at 90 degrees perpendicular to the skin for most adults using 4-mm needles 3
- Rotate injection sites within the same anatomic region (abdomen, thigh, buttock, or upper arm) to prevent lipohypertrophy 3, 4
- Patients with very low BMI (<19 kg/m²) or lean body mass should use a skin lift technique even with 4-mm needles to avoid intramuscular injection 3
- Allow insulin to reach room temperature before injecting—cold insulin causes more pain 3
The bottom line: Your 4-mm, 32-gauge needles work perfectly for both pens and represent the current gold standard for insulin injection across all insulin types and delivery devices.