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

Technical documents: SDS CoA Datasheet

Product overview

Name 4-Hydroxytamoxifen ≥70% Z isomer (remainder primarily E-isomer)
Alternative names 4-OHT, Afimoxifene, H6278, 4-HT, 4-OH-TAM, OHT, TAM, 4-Hydroxytamoxifen, tamoxifen, z-4oht
Purity >98%

Estrogen receptor ligand. For inducible genome manipulation (e.g. Cre-LoxP (CreER)/ TRAP/ CRISPR-Cas9).

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Biological Data

Biological description

Cell permeable, synthetic estrogen receptor ligand. Active metabolite of tamoxifen. Widely used for inducible genome manipulation. ≥70% Z isomer (remainder primarily E-isomer).


Cre-LoxP / CreER system:

De facto standard for use in the inducible Cre-LoxP system for manipulation of CreER/CreERT2 recombinase for genome/ genetic manipulation (e.g. gene deletion). 4-OHT allows external temporal control of Cre activity in vivo.



Used as part of the TRAP/TRAP2 systems (targeted recombination in active populations) (e.g. FosTRAP, ArcTRAP) to provide genetic access to neurons.


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.



Chemotherapeutic agent. Induces apoptosis through an ER-dependent mechanism and inhibits proliferation of multiple myeloma cells in vitro.


Pure (Z)-4-hydroxytamoxifen (100% isomer) also available.

Solubility & Handling

Storage instructions -20°C
Solubility overview Soluble in DMSO (100 mM) and in ethanol (50 mM)

Storage of solid

  • This compound is light sensitive; exposure to light may affect compound performance. You should therefore store the material in the dark and protect from light.

Storage of solutions

  • Do not store the material in solution; make up solutions and use immediately:
  • The compound has been shown to isomerise rapidly in solution in most solvents (particularly solvents with a low dielectric constant). You should therefore make up and use solutions immediately.
  • The isomerisation process can be precluded by storage of the compound at -25°C in the dark as a THF solution containing ca. 0.025% BHT. (Katzenellenbogen et al (1982) J. Org. Chem. 47 2387.)
Important This product is for RESEARCH USE ONLY and is not intended for therapeutic or diagnostic use. Not for human or veterinary use.



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Chemical Data

Purity >98%
Chemical name 4-(1-[4-(Dimethylaminoethoxy)phenyl]-2-phenyl-1-butenyl)phenol
Molecular Weight 387.52
Chemical structure 70% Z-4-Hydroxytamoxifen [68392-35-8] Chemical Structure
Molecular Formula C26H29NO2
CAS Number 68392-35-8
PubChem identifier 449459
Source Synthetic
InChi InChI=1S/C26H29NO2/c1-4-25(20-8-6-5-7-9-20)26(21-10-14-23(28)15-11-21)22-12-16-24(17-13-22)29-19-18-27(2)3/h5-17,28H,4,18-19H2,1-3H3/b26-25-
Appearance Off-white solid

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

References are publications that support the biological activity of the product
  • Temporal evolution of cortical ensembles promoting remote memory retrieval

    Luo et al (2019) Nat Neurosci. 22(3) : 460-469
  • A chemical-inducible CRISPR-Cas9 system for rapid control of genome editing.

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

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

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

    Jordan et al (1977) J Endocrinol 75(2) : 305-16.

5 Item(s)

These publications cite the use of 4-Hydroxytamoxifen ≥70% Z isomer (remainder primarily E-isomer) purchased from Hello Bio:
  • Horizontal basal cells self-govern their neurogenic potential during injury-induced regeneration of the olfactory epithelium.

    Louie JD et al (2023) Development (Cambridge, England) 150
    PubMedID: 37260223
  • Microglial pattern recognition via IL-33 promotes synaptic refinement in developing corticothalamic circuits in mice.

    Han RT et al (2023) The Journal of experimental medicine 220
    PubMedID: 36520518
  • The parasubthalamic nucleus refeeding ensemble delays feeding initiation

    Dunning et al (2023) bioRxiv : https://doi.org/10.1101/2023.01.28.525750
  • ZBP1 sequesters cGAS in the cytoplasm and sustains type I interferon responses to mitochondrial DNA

    Lei et al (2022) Biorxiv : https://doi.org/10.1101/2022.05.30.493783
  • A forebrain neural substrate for behavioral thermoregulation

    Jung et al (2022) Neuron. 110(2) : 266-279
    PubMedID: 34687664

Items 1 to 5 of 8 total