Testosterone HRT and critical flicker frequency
Research type
Research Study
Full title
“Does adding in testosterone to traditional HRT have an impact on critical flicker fusion frequency after 3-6 months of use?”
IRAS ID
353133
Contact name
Madeleine Crow
Contact email
Sponsor organisation
Locala
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
We will explore: “Does adding in testosterone to traditional HRT have an impact on critical flicker fusion frequency (CFFF) after 3-6 months of use?” The critical flicker fusion frequency (CFFF) is the point at which an observer perceives a previously flickering light source to be stable and no longer flickering. This occurs when the frequency of the flicker surpasses that which the human brain is able to perceive. CFFF has been measured in numerous medical conditions and has been suggested to be as a marker of cortical dysfunction.
This is a single-arm trial. Patients will be recruited during routine phone clinic appointments and CFFF measurements will be taken on sight during blood test appointments. We propose to recruit patients about to start testosterone alongside their existing systemic HRT. Participants will have their CFFF measured using a headset. Ten measurements will be obtained taking roughly ten minutes to complete. This will be done at an initial appointment before commencing testosterone, and then at a follow-up appointment once they have been taking it for 3-6 months.
REC name
London - Bromley Research Ethics Committee
REC reference
25/PR/0993
Date of REC Opinion
19 Nov 2025
REC opinion
Further Information Favourable Opinion