Alexa Fluor® 555 dyeProbes with high fluorescence quantum yield and high photostability allow detection of low-abundance biological structures with great sensitivity. Alexa Fluor® 555 dye molecules can be attached to proteins at high molar ratios without significant self-quenching, enabling brighter conjugates and more sensitive 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.


Alexa Fluor® 555 dye dashboard

Initial brightness

Recommended replacement for tetramethylrhodamine or Cy®3 dye, exhibiting greater photostability than Cy®3 dye in live and fixed cells. In addition, is used in stochastic optical reconstruction microscopy (STORM)—as an activator in nSTORM and a reporter in dSTORM.

Photostability in buffer


Photostability in antifade


Performance in SRM


  488/532 TRITC 555 580  
Laser line

Common filter set

Excitation max

Emission max


Alexa Fluor® 555

FluoCells® prepared slide #6 showing a fixed, permeabilized, and labeled muntjac skin fibroblast. Mitochondria were labeled with anti–Oxphos Complex V inhibitor protein mouse IgG1 and visualized using orange-fluorescent Alexa Fluor® 555 goat anti–mouse IgG. F-actin was labeled with green-fluorescent Alexa Fluor® 488 phalloidin, and the nucleus was stained with TO-PRO® 3 iodide (pseudocolored magenta).

Alexa Fluor® 555 reactive dyes

Select dye-labeling chemistries for conjugation with the following reactive groups: 

Amine Thiol Aldehyde-, ketone, carboxylate or phosphate Click reaction

Alexa Fluor® dye family

Illuminating research for over 15 years

Alexa Fluor® dyesAlexa Fluor® dyes are among the most trusted fluorescent dyes available today. In addition to superior performance, you’ll get a technical support team experienced in problem-solving, >50,000 published references, application and experimental tips, and protocols to help with experimental planning. For an outstanding research experience, choose Alexa Fluor® dyes.



Molecular Probes® Handbook

Molecular Probes HandbookThe significantly revised 11th Edition is the most complete fluorescence labeling and detection reference available. The Molecular Probes® Handbook can help you achieve the best experimental results for your fluorescence labeling and detection experiments. View the handbook online or order your own copy.


Antifade reagents

Antifade reagentsAntifade reagents suppress photobleaching and preserve the signals of your fluorescently labeled target molecules. They offer excellent compatibility with Alexa Fluor® 555 dye and a multitude of dyes across the spectrum, making them especially valuable tools for multicolor applications.

Cell stain tool

Cell stain toolStain your own cell by using our simulation tool to develop reproducible results with many of our signature fluorescent dyes. Develop your multiplexing strategy for antibody probes, reactive dyes, and counterstains to create your perfectly labeled fluorescent cell.


Fluorescence SpectraViewer

Fluorescence SpectraviewerPlot and compare spectra and check the spectral compatibility for common fluorophores including all the Molecular Probes® fluorescent probes. The Fluorescence SpectraViewer tool is formatted for both microscope imaging and flow cytometry applications.

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