Fluorescent-dye conjugated secondary antibodies provide a tool for identifying proteins in many applications including fluorescent cell imaging, western blotting, immunohistochemistry and more. The advantages of using a fluorescently labeled secondary antibody include brighter signal, multiplexing capabilities, and ease of use. Browse our portfolio of Alexa Fluor secondary antibodies, classic secondaries (such as FITC and TRITC), and our selection of enzyme and biotin-labeled secondaries.

Alexa Fluor Plus Secondary Antibodies

Need to detect and visualize low-abundance targets in rare or precious samples?

Alexa Fluor Plus Secondary Antibodies

Compare to traditional Alexa Fluor secondary antibodies:

  • Higher signal-to-noise ratio
  • Lower cross-reactivity

Learn more

Quick links to secondary antibody conjugate products

Quick links to fixatives, mountants and other organelle staining reagents for use with secondary antibodies

Popular fluorescent secondary antibodies

Compare fluorophore conjugate technologies

See how classical fluorophore, Alexa Fluor, and Alexa Fluor Plus secondary antibody conjugates compare.

  Classical fluorophore conjugates Alexa Fluor conjugates Alexa Fluor Plus conjugates
What conjugate products are available? APC
Texas Red
Texas Red-X
Conjugates of 18 Alexa Fluor dyes Conjugates of 6 Alexa Fluor Plus dyes
Use For detection of high-abundance targets   For use with easy-to-obtain samples For detection of medium- to high-abundance targets   For use in most research areas For detection of low-abundance targets   For use with hard-to-obtain samples, e.g., neuroscience  
  • Cell Imaging
    • Immunohistochemistry (IHC)
    • Immunocytochemistry (ICC)
    • Immunofluorescence (IF)
  • Multiplex, fluorescent Western blotting (WB)
Signal-to-noise ratio Low Medium High
Photostability Varying levels of photostability, depending on dye Photostable Photostable
Specificity Various options available Various options available Highly specific, low cross-reactivity (highly cross-adsorbed)
Sensitivity and brightness Lower sensitivity and brightness compared to leading Alexa Fluor conjugates Widely recognized standard for brightness and sensitivity Improved sensitivity and brightness over leading Alexa Fluor conjugates in IF/ICC imaging and fluorescent western blotting
Range of linear detection Low Medium High

Featured secondary antibody conjugate categories

Select from 18 different individual Alexa Fluor dyes and 4 Alexa Fluor tandem dyes as secondary antibody conjugates. Alexa Fluor secondary antibodies exhibit superior brightness and photostability, outperforming conventional fluorescent secondary antibodies. 

Learn about Alexa Fluor Plus secondary antibodies, which represent an advancement in fluorescent conjugate technology, designed to provide brighter signal, enhanced sensitivity, and minimal cross-reactivity in a variety of applications.

Discover features and varieties of available horseradish peroxidase (HRP), alkaline phosphatase (AP), biotin, and other enzyme or affinity-tagged secondary antibody conjugates.

Determine which Alexa Fluor secondary antibodies fit your imaging or western blotting needs by using our instrument compatibility table to guide you. Microscope, microplate reader, high-content platform and fluorescent western blotting compatibility information are also provided.