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4-Hydroxytamoxifen ≥70% Z isomer (remainder primarily E-isomer)


Product overview

  • Name
    4-Hydroxytamoxifen ≥70% Z isomer (remainder primarily E-isomer)
  • Short description
    Synthetic estrogen receptor ligand. Widely used in genome engineering (e.g. CreER/ CRISPR-Cas9).
  • Biological description

    Cell permeable, synthetic estrogen receptor ligand. Widely used in genome engineering. ≥70% Z isomer (remainder primarily E-isomer).

    CreER system:

    De facto standard compound in drug-inducible manipulation of CreER recombinase. Allows external temporal control of Cre activity in vivo .

    CRISPR/Cas9 gene editing:

    Activates an inactived Cas9 nuclease (rendered inactive by insertion of a 4-OHT dependent-intein) to reduce off-target CRISPR-mediated gene editing (once bound with 4-OHT, conditionally active Cas9s modify target genomic sites with ~25-fold higher specificity than wild-type Cas9).

    Also allows tight, repeated on-off control of the nuclease activity of the ‘iCas’ Cas9 variant which shows high editing efficiency at multiple loci once bound with 4-OHT.

    Pure (Z)-4-hydroxytamoxifen also available.

  • Alternative names
    4-HT, 4-OHT, 4-OH-TAM, OHT, TAM, 4-Hydroxytamoxifen
  • Biological action
  • Purity
  • Citations


  • Chemical name
  • Molecular Weight
  • Chemical structure
    70% Z-4-Hydroxytamoxifen [68392-35-8]
  • Molecular Formula
  • CAS Number
  • PubChem identifier
  • Source
  • InChi
  • InChiKey
  • Appearance
    Off-white solid

Storing and Using Your Product

  • Storage instructions
  • Solubility overview
    Soluble in DMSO (100 mM) and in ethanol (50 mM)
  • Handling
    This compound is light sensitive; exposure to light may affect compound performance. We therefore recommend storing the material in the dark and protecting from light. Do not store the material in solution; make up solutions and use immediately.
  • Important
    This product is for RESEARCH USE ONLY and is not intended for therapeutic or diagnostic use. Not for human or veterinary use.

References for 4-Hydroxytamoxifen ≥70% Z isomer (remainder primarily E-isomer)

  • A chemical-inducible CRISPR-Cas9 system for rapid control of genome editing.

    Liu et al (2016) Nat Chem Biol 12(11) : 980-987.
    PubMedID: 27618190
  • Small molecule-triggered Cas9 protein with improved genome-editing specificity.

    Davis et al (2015) Nat Chem Biol 11(5) : 316-8.
    PubMedID: 25848930
  • Simple and efficient production of (Z)-4-hydroxytamoxifen, a potent estrogen receptor modulator.

    Yu and Forman (2003) J Org Chem 68(24) : 9489-91.
    PubMedID: 14629178
  • A monohydroxylated metabolite of tamoxifen with potent antioestrogenic activity.

    Jordan et al (1977) J Endocrinol 75(2) : 305-16.
    PubMedID: 591813
Support & Resources


  • Verified customer

    A good replacement for all Z 4OHT. This 70% Z+30% E 4OHT worked for us. We followed the protocol in a recent paper which used 70% Z as well.
  • Verified customer

    Our experiment indicated 70% 4OHT was enough to activate cre recombination in our lines. This is really satisfying for us. So, we would like to use 70% 4OHT Tamoxifen, instead of classic 4OHT Tamoxifen from your company for our next experiment.
  • Verified customer

    Excellent. We achieved excellent recombination using this product on our cre-lox mouse cross. This product also had the best price found across vendors.