Metal vs Plastic Injection Pen: Which is Better for Biologics?

As biologic therapies such as GLP-1, insulin analogs, and peptide-based drugs continue to grow, the choice of injection pen material has become a critical consideration. Pharmaceutical companies and device developers are increasingly evaluating whether metal injection pens or plastic injection pens provide better performance, durability, and patient experience.

metal reusable pen

Compares both options from a drug delivery and manufacturing perspective to helpe you determine the best fit for biologics.

1. Material Overview: Metal vs Plastic Injection Pens

Metal Injection Pens

Typically made from aluminum or stainless steel, metal pens are designed for reusability, structural strength, and premium feel.

Plastic Injection Pens

Usually made from medical-grade polymers, plastic pens are widely used in disposable or prefilled pen systems due to cost efficiency and scalability.

injecion pen types

2. Comparison for Biologic Drug Delivery

Durability and Lifecycle

Metal pens: High durability, long lifecycle, resistant to mechanical wear

Plastic pens: Suitable for single-use or short-term use, lower structural strength

For biologics requiring chronic administration (e.g., GLP-1 therapies), metal pens offer better long-term reliability.

Dose Accuracy and Injection Performance

Metal pens: More stable internal structure, improved dose precision over time

Plastic pens: Adequate accuracy, but may be affected by wear or deformation

Precision is critical for biologics and peptide drugs, making metal pens advantageous in premium applications.

Compatibility with Biologics

Biologic drugs are often:

Sensitive to temperature and agitation

High-value and complex formulations

Metal pens: Provide better mechanical protection and stability

Plastic pens: Sufficient for standard formulations but less robust

User Experience and Perception

Metal pens: Premium, ergonomic, often preferred in high-end therapies

Plastic pens: Lightweight, functional, widely accepted for mass-market use

reusable pen

Cost and Manufacturing

Metal pens:

Higher initial cost

Suitable for reusable platforms

Lower long-term cost per use

Plastic pens:

Lower upfront cost

Ideal for disposable systems

High-volume manufacturing advantage

Sustainability

Metal pens: Reusable, environmentally friendly over lifecycle

Plastic pens: Single-use waste concerns

3. When to Choose Metal Injection Pens

Metal pens are the better choice when:

Developing premium biologic therapies

Targeting long-term or chronic treatment markets

Focusing on brand differentiation and patient experience

Offering reusable drug delivery platforms

Supporting OEM/ODM customization

4. When Plastic Injection Pens Make More Sense

Plastic pens are ideal for:

High-volume disposable products

Cost-sensitive markets

Short-term therapies

Standardized drug delivery systems