I called and was directed to the USP website which states:

Products that meet the program's stringent criteria are awarded the distinctive USP Verified Mark for use on labels, packaging, and promotional materials. The Mark makes it easy for customers, healthcare practitioners, and retailers to identify USP Verified products. Seeing the USP Verified Mark on a label indicates that the dietary supplement product inside:

Contains the ingredients listed on the label, in the declared potency and amounts.
Does not contain harmful levels of specified contaminants.
Will break down and release into the body within a specified amount of time.
Has been made according to FDA current Good Manufacturing Practices using sanitary and well-controlled procedures.

USP conducts a rigorous process of tests and reviews before awarding the USP Verified Mark to a dietary supplement that a manufacturer voluntarily submits for verification. The process includes the following steps:

Experienced USP scientists test supplement products to ensure that they meet USP standards for quality, purity, and potency. This includes testing dietary supplement products and their ingredients against dietary supplement standards found in The United States Pharmacopeia and The National Formulary (USP–NF).
USP conducts a thorough manufacturing and quality control/product document review.
USP performs an on-site manufacturing facility audit for compliance with USP standards and FDA current Good Manufacturing Practices (21 CFR Part 111).
After a product is verified, USP performs random, off-the-shelf testing to confirm that it continues to meet USP's strict standards.


Now with all that being said. I am confident that the Kirkland B12 Methyl is pure and potent.

http://www.usp.org/usp-verification-...ry-supplements

The above is the link for the info.