Cy®3 dye

Invitrogen Cy3 dye is a bright, orange-fluorescent dye that can be excited using the 532 nm laser line and visualized with TRITC (tetramethylrhodamine) filter sets. In addition to immunocytochemistry applications, Cy3 dye is commonly used to label nucleic acids.

The Cy3 fluorophore is also the basis for the lipophilic neuronal and long-term DiI cell tracing reagents, which append alkyl tails (≥12 carbons) onto the core fluorophore.

Invitrogen Alexa Fluor 555 dye is a Cy3 dye alternative that is generally more fluorescent and more photostable than Cy3 dye, making it well suited for applications such as imaging and flow cytometry.

Cy3 dye dashboard

Initial brightness

The Cy3 dye is a traditional orange-fluorescent label for protein and nucleic acid conjugates used for imaging, flow cytometry, and genomic applications. It is also the basis for the classic lipophilic tracer DiI and its variants. 

Photostability in buffer


Photostability in antifade


Cy3 products

We offer a range of Cy3 dye and DiI products including secondary antibodies, streptavidin conjugates, kits, and more. Learn more here:

Learn more about fluorescent dyes in the Cy3 dye wavelength range

See all Cyanine3 Primary Antibodies
See all Cyanine3 Secondary Antibodies


Double labeling of tubulin and HA-tagged tubulin in T. thermophila using Cy3-goat anti-rabbit and FITC-goat anti-mouse.

High-performance alternatives to Cy3 dye

Fluorescent conjugates

The Alexa Fluor 555 dye—with nearly identical spectral properties to Cy3 dye—produces brighter, more photostable conjugates. These conjugates are ideal for imaging and other applications requiring increased sensitivity and environmentally insensitive fluorescence detection.

We offer Alexa Fluor 555 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection. In addition, reactive dye forms and protein labeling kits are available to allow you to generate your own antibody conjugates or probes.

Learn more about Alexa Fluor 555 dye

Comparison of the relative fluorescence of goat anti–rabbit IgG antibody conjugates of Alexa Fluor 555 and Cy3 dyes (prepared in our laboratories) at different dye:protein ratios in the conjugate.

Not for resale. Super Bright Polymer Dyes are sold under license from Becton, Dickinson and Company.

Brilliant Ultra Violet™ and Brilliant Violet™ are trademarks or registered trademarks of Becton, Dickinson and Company or its affiliates, and is used under license.

For Research Use Only. Not for use in diagnostic procedures.