Scientist / Senior Scientist, Peptide Chemistry

About the role

We are a vibrant and intensely mission-driven team in San Francisco, comprising members from MIT, Harvard Medical School, Roche, ETH, and Dana-Farber. We value speed and rigor, coupled with excitement, drive, and a strong work ethic. In an early-stage environment, we value people who can bring clarity to open-ended problems, take ownership of the next steps, and follow through with energy. Capable Labs is a place for ambitious, high-integrity people who want to become dramatically better. You will be surrounded by people who care intensely about the work, get close feedback from the people making scientific and company-defining decisions, and have room to own increasingly important problems. We believe excellent work should be met with meaningful reward, ownership, and trust. Responsibility is earned through contribution, not title alone: anyone who demonstrates the judgment, rigor, and follow-through to move important work forward can earn meaningful scope.

Responsibilities

• Lead and scale end-to-end peptide synthesis workflows, including sequence design, resin loading, coupling/deprotection cycles, cleavage, purification, and analytical characterization.
• Run microwave-assisted solid-phase peptide synthesis, maintain the synthesizer, and troubleshoot failed couplings, low crude purity, side products, cleavage issues, and instrument downtime.
• Purify and characterize compounds using HPLC, prep HPLC, LC-MS, and related methods; track identity, purity, yield, and batch-level QC before handoff.
• Design next-round compounds from SAR, in vitro, and in vivo readouts, using potency, stability, and tolerability data to decide what we make next.

Requirements

• 5+ years of hands-on industry experience in organic, medicinal, or peptide chemistry, with strong experimental judgment, deep troubleshooting ability, and a high bar for execution.
• Excited to own synthesis end-to-end: designing compounds, running reactions, purifying and characterizing them, and preparing them for testing with care and urgency.
• Enjoy solving problems creatively, iterate fast, and keep the science rigorous.
• Like being close to the biological readout. You want to understand how compounds perform in vitro and in vivo, then use potency and efficacy data to inform the next design cycle.
• Take responsibility for your work. When an instrument breaks, a synthesis fails, or a handoff is unclear, you troubleshoot and communicate clearly.

Benefits

• $165,000-$220,000 salary, plus equity options with an implied current value of approximately $50,000-$200,000 before exercise cost, taxes, dilution, and liquidity risk.
• $500+ monthly wellness budget for training, supplements, coaching, recovery, or other tools that help you perform at your best.
• Healthcare: broad range of medical, dental, and vision coverage options, with Capable covering 100% of the base policy. Access to HSA, FSA, and 401K plans.
• Healthy dinners with the team provided daily.
• Visa sponsorship support, including O-1, H-1B, J-1, TN, and other employment-based pathways.

Our team is already international, with members from Canada, Pakistan, Germany, Austria, Switzerland, China, India, and the United States.