Custom Fit SF

Custom Fit SF is a data-driven fitness and longevity testing studio founded by Evan and Marissa Mather in San Francisco's Hayes Valley neighborhood. The 8,000 sq ft facility pairs clinical-grade diagnostics — Hologic DEXA body composition scanning, a 50+ biomarker advanced bloodwork panel, VO2 Max and Resting Metabolic Rate testing, and genetic analysis — with on-staff Registered Dietitians and ACSM-certified Exercise Physiologists who review results with clients same-day. The studio positions testing as the core product rather than an add-on, offering individual services or the all-in-one Longevity Blueprint package ($1,250) that combines all assessments into a single appointment sequence. A second location operates at 1844 Market Street in the Upper Market/Castro neighborhood, and a third Financial District location is in development. Membership tiers provide unlimited access to DEXA and VO2 testing for regular trackers. The team includes Registered Dietitian Nutritionists, an ACSM Exercise Physiologist and RunDNA Gait Analyst, a Physical Therapist, and Dr. Jahan Fahimi (MD) available for physician-level bloodwork consultations.