How to Identify an Unknown Capsule
Capsules present unique identification challenges compared to tablets because they often lack the embossed imprint codes that make tablet identification straightforward. This guide explains the key features to examine when trying to identify an unknown capsule, and how to use our Capsule Identifier effectively.
Hard vs Soft Gel Capsules
Understanding whether you have a hard or soft gel capsule is the first step. Hard capsules consist of two separate rigid pieces - a cap and a body - that fit together. They typically contain powders, granules or pellets. The two halves are usually different colors, and most printed text appears on the body or cap surface. Soft gel capsules are a single seamless unit made of a flexible gelatin shell containing a liquid or semi-solid fill. They include fish oil, vitamin E, and certain medication formulations like liquid ibuprofen capsules. HPMC capsules look identical to gelatin hard capsules but are made from hydroxypropyl methylcellulose for vegetarian patients - they are typically identified by a "V-caps" or "HPMC" notation on the packaging rather than on the capsule itself.
Identifying Hard Capsules
For hard two-piece capsules, record the following: the color of the cap (upper, shorter piece), the color of the body (lower, longer piece), any printed text on either piece, the capsule size (use the size reference in our tool - size 0 is the most common prescription capsule at approximately 21mm), and whether there is a colored band or stripe at the join. Common prescription hard capsule examples include fluoxetine (green/green - Prozac), omeprazole (pink/pink - Prilosec), esomeprazole (purple/purple - Nexium) and amoxicillin (pink/red). Once identified, check the medication's interactions using our Drug Interaction Checker.
Capsule Size Reference
Hard gelatin capsule sizes are standardised from 000 (largest, ~22mm, ~1.37mL volume) down to 5 (smallest, ~11mm, ~0.13mL). The most commonly dispensed sizes for oral medications are sizes 0, 1 and 2. Size 00 is used for larger doses. Size 000 is rarely used for oral medications - it is the largest size and is more common in veterinary or compounding applications. If you are unsure of the size, measure the capsule's length: approximately 14mm = size 2, 16mm = size 1, 21mm = size 0, 23mm = size 00.
When You Cannot Identify the Capsule
If the capsule has no visible imprint, is a single uniform color with no markings, or our tool returns too many candidates to narrow down, take it to a pharmacist. Do not open, smell or taste an unknown capsule. Never take an unidentified capsule. Pharmacists have professional identification databases and the clinical expertise to identify capsules you cannot identify yourself. After identification, use our Side Effect Checker and Contraindication Checker for comprehensive medication information.