NMR Shift Reagents
- Supplier of NMR shift reagents.
- http://www.rareearthproducts.com/nmrshiftreagents.htm

Medical Isotopes, Inc.
- Nearly a complete line of enriched biochemicals. Nice selection of fatty acids, enriched with C13.
- http://www.medicalisotopes.com/

Isotec
- Makes some of the most unique and novel labeled compounds
- http://www.isotec.com/

C/D/N ISOTOPES
- Quite a large listing of deuterated compounds and Carbon-13 and Nitrogen-15 labelled compounds. In English or German or French.
- http://www.cdniso.com/

Cambridge Isotope Laboratories
- Manufacturer of stable isotope labeled compounds and some fine deuterated solvents too.
- http://www.isotope.com/

Silantes GmbH
- Stable isotope labeled biopolymers (H2, C13, N15)
- http://www.silantes.com/