Type I vs Type III Glass: Which One Does Your Product Need?

Why glass type matters

Not all glass packaging is made the same way, and the difference isn't cosmetic — it affects how the glass reacts chemically with what's inside it. The US Pharmacopeia (USP) classifies pharmaceutical and lab glass into types based on chemical resistance, and buyers outside pharma often borrow the same shorthand when specifying packaging.

Type I — borosilicate glass

Type I glass is borosilicate, the most chemically resistant and inert of the standard types. It resists leaching even from reactive or high-pH formulations, and is the default for injectable (parenteral) drug packaging and tubular vials. It costs more to produce and is typically reserved for products where chemical purity is critical.

Type II — treated soda-lime glass

Type II is ordinary soda-lime glass that's been surface-treated (usually with a sulfur or ammonium sulfate process) to reduce alkali leaching from the inner surface. It's less common in general packaging and mainly used for some parenteral products where Type I isn't required.

Type III — soda-lime glass

Type III is standard soda-lime glass with no special surface treatment. It's the workhorse of the packaging world — used for most oral liquids, tablets and capsules in pharma, and for the vast majority of food, beverage, cosmetics and fragrance glass. It's less chemically resistant than Type I, but perfectly suitable for products that aren't sensitive to the mild alkalinity of untreated glass.

The tests behind the label

Two USP tests are what actually confirm a glass type rather than just its stated name:

• USP <660> — tests the glass itself (surface glass test and/or powdered glass test) to confirm which type it is
• USP <671> — measures light transmission, which is what determines whether an amber or opaque container adequately protects a light-sensitive formulation

Which type does your product need?

As a general guide: injectable or highly reactive formulations usually specify Type I; most oral liquids, tablets, capsules, food, beverage, cosmetic and fragrance products are packaged in Type III without issue. The final call on glass type for a regulated product belongs to your formulation or regulatory team — but we can quote either, and provide USP <660> and <671> documentation with your order where it applies.

See our Pharmaceutical glass range for Type III and Type I options, or the documents we collect on our Quality & documentation page.