Senior / Principal Scientist - Peptide Chemistry

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.

About the Role

You will lead peptide-chemistry execution on a dedicated night-shift schedule, keeping synthesis, purification, characterization, and biological handoffs moving around the clock. You will make sound technical decisions independently, solve difficult chemistry and instrument problems, and ensure the day team receives complete, decision-ready work each morning.

Responsibilities

• Lead overnight peptide synthesis from route or sequence planning through reaction setup, solid- or solution-phase synthesis, cleavage, purification, characterization, and sample preparation.

• Run and optimize microwave-assisted solid-phase peptide synthesis, including resin loading, coupling and deprotection cycles, crude analysis, and final quality control.

• Resolve difficult overnight issues involving failed reactions, low conversion or purity, side products, solubility, cleavage or deprotection, purification, and instrument downtime.

• Purify and characterize compounds using analytical HPLC, prep HPLC, LC-MS, NMR, and related methods as appropriate.

• Own identity, purity, yield, analytical traces, batch records, and sample readiness for in vitro and in vivo testing.

• Contribute chemistry insight on feasibility, SAR, stability, solubility, yield, and structure-property relationships to guide the next compounds.

• Provide disciplined morning handoffs covering results, failures, technical decisions, sample locations, risks, and follow-up actions.

Ideal Qualifications

• Able and willing to work the designated night-shift schedule reliably and make consequential technical decisions independently when needed.\

• Five or more years of hands-on industry experience in peptide, medicinal, organic, or closely related chemistry.

• Strong synthetic-chemistry fundamentals, experimental judgment, and deep troubleshooting ability; direct peptide experience is helpful.

• Experience owning chemistry end to end, including design, synthesis, purification, characterization, quality control, and preparation for biological testing.

• A fast, rigorous, and safety-conscious working style with excellent experimental records.

• The ability to lead through technical judgment and create clean, useful handoffs across night and day teams.

Pay & Benefits

• Compensation and equity will depend on the skills, experience, and scope of impact you bring. We are open to a conversation based on the scope and impact you could bring.

• $500+ monthly wellness budget for training, supplements, coaching, recovery, or other tools that help you perform at your best.

• Healthcare: We offer a broad range of medical, dental, and vision coverage options, with Capable covering 100% of the base policy.

• You will also have access to HSA, FSA, and 401K plans.

• Healthy vegetarian dinners with the team are provided daily.

• We support visa sponsorship where appropriate, 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.

Application Process

Our process is fast, transparent, and personal. We care about getting to know the person behind the application.

• Initial application

• First phone screen

• Second phone screen

• In-person on site work trial in San Francisco: designed to give both sides a realistic sense of working together. Get to know the founding team!

Apply Today

Curious but not sure? Apply anyway. It takes 5 minutes, and you do not need to be actively job searching to start a conversation.

Some of the best people do not map perfectly to a job description. If this sounds like a place where you could do important work, we would like to hear from you.

And if someone exceptional comes to mind, send them our way here. We read every referral carefully, and if your referral joins Capable, we’ll send you a thank-you bonus.

Equal Opportunity

Capable is an Equal Opportunity Employer; employment with Capable is governed on the basis of merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.