Function Health

Sacra estimates that Function Health hit a $100M revenue run rate in February 2025, up approximately 450% year-over-year. This rapid growth has been fueled by an expanding subscriber base that reached over 200,000 members by May 2025, compared to approximately 40,000 in May 2024.

The company has demonstrated accelerating growth rates throughout its short history. After launching in 2023, Function initially added about 170 subscribers daily in the second half of 2023, slowed to 110 daily in the first half of 2024, then accelerated to 260 daily in the second half of 2024, before reaching over 800 subscribers daily in early 2025.

At $499 per annual subscription, the core blood testing service forms the foundation of Function's revenue. Additional revenue comes from premium add-on tests beyond the basic subscription, potentially adding around $8M in non-recurring revenue (at an estimated $39 per subscriber annually), as well as B2B partnerships such as the collaboration with Equinox for their ultra-premium $40K "Optimize" tier.

In November 2025, Function Health raised a $298M Series B led by Redpoint Ventures at a $2.5B valuation.

The round included a16z, Aglaé Ventures, Alumni Ventures, Battery Ventures, NFDG (Nat Friedman & Daniel Gross), Anthony Wood (Roku founder), and NBA investors Allen Crabbe, Blake Griffin, and Taylor Griffin.

Function Health’s total funding is $350M.

Function Health offers a direct-to-consumer blood testing service with a $365 annual subscription. Members receive two comprehensive blood tests per year — the first measuring 100+ biomarkers and the follow-up tracking 60+ markers.

A typical user journey starts with signing up online, booking an appointment at one of Quest Diagnostics' 2,000+ locations nationwide, completing a blood draw (which can require up to 20 vials for the full panel), and receiving results within days through the Function app.

The app presents results with visual indicators showing where values fall within ranges, accompanied by up to eight pages of notes from clinicians with dietary, exercise, and lifestyle suggestions.

The biomarkers tested go well beyond standard physical exams, including advanced metrics like inflammatory markers, hormone levels, nutrient status, thyroid function, and cancer screening markers.

Unlike concierge medicine services, Function intentionally limits doctor involvement to generating summaries and handling critical alerts, without providing direct consultations or prescriptions.

Function has extended its core offering into imaging through two products. Its full-body MRI, available at $499 (down from Ezra's previous price of $1,495) following the May 2025 acquisition of Ezra, utilizes FDA-cleared AI technology that reduces scan time from the typical hour to just 22 minutes. The MRI service does include a Zoom consultation with a provider to discuss scan results, unlike Function's core blood testing service which doesn't offer direct provider conversations.

Complementing the MRI, Function also offers a Heart & Lungs CT add-on (launched November 2025) that provides lung screening and a remotely analyzed coronary artery calcium score from a single low-dose three-minute CT, priced at $349. Together, these imaging products extend Function's reach beyond bloodwork and offer a faster, lower-cost option for assessing cardiovascular risk.

Function has also built a layer of AI integrations that make member health data portable across major platforms. Members can authorize ChatGPT to access a limited, high-level summary of their lab results for more personalized health prompts — an integration that appears in ChatGPT's app store and ChatGPT Health with secure, revocable access controls.

A parallel connector allows members to securely link their health data with Microsoft Copilot Health, initially rolling out to a limited testing group via waitlist. Together, these integrations position Function's member data as a portable layer accessible across the major consumer AI platforms.

Function Health operates on a B2C go-to-market model with a straightforward annual subscription that monetizes through direct consumer payments of $365 for two rounds of blood tests per year. Add-on services — including a $499 full-body MRI and a $349 Heart & Lungs CT — provide incremental revenue per member.

The company employs an asset-light approach, avoiding the capital-intensive aspects of healthcare by outsourcing lab work to Quest Diagnostics and limiting clinician involvement to test ordering, results review, and flagging critical issues.

Medical oversight comes from contracted telehealth doctors rather than full-time employed physicians, keeping fixed costs low while meeting regulatory requirements. This structure allows Function to maintain high gross margins while positioning itself as a technology and customer experience layer atop existing healthcare infrastructure, and lets it scale efficiently without the labor costs of traditional concierge medicine.

Function benefits from strong volume leverage — members have completed over 50 million lab tests since 2023 — giving it increasing negotiating power with Quest Diagnostics, driving down per-test costs and creating a competitive moat against smaller players.

Customer acquisition costs remain relatively low compared to healthcare industry standards ($300–600 per customer) thanks to co-founder Dr. Mark Hyman's 2.6M Instagram followers, celebrity investor endorsements, and a growing waitlist that creates built-in demand and word-of-mouth growth.

Function has built out multiple B2B2C distribution channels that reduce dependence on direct consumer marketing. It serves as the NBPA's exclusive Biomarker Partner for active and retired NBA players. John Hancock became the first life insurer to offer Function access, extending subsidized membership to eligible Vitality PLUS members.

Equinox offers members a first-year Function membership at $249 and has tapped Function to power EQX ARC, Equinox's women's health offering, including a full women's hormone panel. Insurance brokerage Higginbotham has added Function to its employee well-being portfolio at $334 annually. Collectively, these partnerships extend Function's distribution into employer benefits, professional sports, insurance, and premium fitness — reducing its dependence on paid consumer acquisition.

Beyond testing, Function has evolved its core product toward a longitudinal health-management platform. Its Medical Intelligence Lab unifies lab, imaging, wearables, and health-records data, and introduces capabilities including Private AI Chat, Protocols, and health-record uploads that generate actionable guidance tied to a member's biomarkers and scans. This positions Function less as a periodic testing service and more as an ongoing intelligence layer for members managing their health over time.

The $250-$499 blood testing segment has become increasingly crowded and price-competitive. Instalab offers 60+ biomarkers for $250 with buy-now-pay-later options through Klarna.

Mito Health provides 100+ biomarkers for $360 (recently discounted 15% from $399) and includes 1-to-1 physician consultations that Function lacks. Everlywell, one of the earliest entrants (founded 2015), offers a Function-like membership for $399 annually that tracks 83 biomarkers and has mature distribution channels through pharmacies and retailers.

These competitors are driving down prices while expanding service offerings, forcing Function to justify its $499 price point. Many customers in health forums highlight Mito's more high-touch approach with personalized health plans, while some criticize Function's clinician notes as appearing generic or AI-generated.

A parallel market of bare-bones lab testing providers has emerged with even lower price points. WalkinLab, Private MD Labs, and Own Your Lab offer customizable, low-cost panels significantly cheaper than Function.

Private MD Labs' "Anti Aging" test bundle (comparable to Function's offering) requires just $1 upfront payment to order tests, with customers paying $377 for an annual subscription or $444 for a one-time purchase after visiting the testing center.

Many of these discounters operate primarily in states with fewer regulatory hurdles, often excluding New York, New Jersey, and Massachusetts due to their tighter restrictions on lab testing.

Though limited in geographic scope, these providers represent a growing threat to Function's value proposition as they normalize lower price points for similar services.

While Function focuses primarily on testing and analysis without providing treatment, competitors are building more comprehensive healthcare solutions. Superpower makes it easy to message medical teams about results, integrates wearables data, and offers a marketplace for supplements and wellness products.

Hims & Hers' acquisition of Trybe Labs positions them to combine at-home testing with immediate treatment options through their existing telehealth platform.

Whoop’s September 2025 launch of Advanced Labs—Quest Diagnostics blood panels integrated with its continuous wearable monitoring at $199–$599/year—pushes the brand into the out-of-pocket wellness testing lane alongside Function Health, intensifying competition on price, cadence, and longitudinal biometrics.

Traditional insurers are also pivoting toward value-based care models that emphasize preventive screenings.

As major insurers like UnitedHealth Group and Cigna expand their preventive health offerings, Function may need to differentiate beyond its current testing suite or potentially partner with these insurers to maintain growth in a market where prevention is gradually becoming standard rather than premium.

Function Health has begun expanding beyond blood testing into other diagnostic realms.

The acquisition of Ezra in May 2025 represents their first major step, bringing full-body MRI scanning capabilities into their offering at a market-disrupting price of $499 (down from Ezra's previous $1,495). This dramatically expands their addressable market by making high-end imaging accessible to their middle-income customer base rather than just the wealthy.

The partnership with GRAIL to offer their Galleri multi-cancer early detection test as an add-on service further signals this expansion strategy.

Future integration opportunities include genetic testing, gut microbiome analysis, and continuous glucose monitoring - all complementary diagnostics that could be bundled into Function's platform at scale-enabled pricing. By consolidating multiple diagnostic modalities under one subscription, Function aims to capture more healthcare spending per customer.

Function is actively pursuing B2B channels to dramatically scale beyond its current direct-to-consumer base. The company has stated it's focused on securing deals with large Fortune 500 employers and eventually payers including Medicare and Medicaid.

This approach aims to transform Function's 200,000+ member base into potentially millions of covered lives by embedding its testing platform within existing healthcare benefits systems.

The company has already established strategic footholds in this direction through partnerships with Thrive Global (creating an employee health testing benefit) and the National Basketball Players Association (as their exclusive biomarker partner).

The Equinox collaboration, while targeting high-end individual consumers, demonstrates Function's ability to integrate into established wellness brands. Success in the employer market would provide more predictable revenue streams and lower customer acquisition costs compared to direct-to-consumer marketing.

Function is positioning itself as the future central hub for all health data, moving beyond just offering tests to becoming a comprehensive health analytics platform.

With over 5 million test results already collected, the company is building a longitudinal dataset that could enable AI-driven insights competitors at smaller scale would struggle to replicate.

Future opportunities include integrating wearables data, traditional electronic health records, and creating a unified platform that combines "all of your health data with all of the world's health knowledge" for personalized guidance.

This evolution toward becoming a health data platform rather than merely a testing service significantly expands Function's potential market beyond preventative testing into the broader digital health ecosystem, estimated to reach hundreds of billions globally.

Subscription fatigue: Function relies on discretionary consumer spending for ongoing $499 annual subscriptions, making it vulnerable to economic downturns and value perception issues. After the initial novelty of comprehensive testing, subscribers may struggle to justify continued payment if their results remain largely normal or show minimal changes, potentially driving high churn rates that would force Function to continuously acquire new customers at increasing costs.

Price compression: The preventative testing market is already sliding toward commoditization with competitors like Mito ($360), Instalab ($250), and numerous no-frills providers undercutting Function's price point. This race-to-the-bottom dynamic threatens Function's margins and could force either significant differentiation through value-added services (which would complicate their asset-light model) or price reductions that would impact profitability.

Regulatory uncertainty: Function operates in a regulatory gray area that could become more challenging if state regulations around direct-to-consumer lab testing tighten or if the medical establishment pushes back against what some physicians view as unnecessary over-testing. The company already faces special handling requirements and fees in states like New York and New Jersey, and any broad regulatory shifts could force significant model adjustments, while concerns about false positives leading to unnecessary follow-up procedures present both reputational and potential legal risks.