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    Stable Isotope Research Applications

    Stable Isotope Assays for Energy Expenditure Measurement with the Doubly Labeled Water (DLW) Protocol

    We provide project design assistance and stable isotope analysis services to help researchers determine energy expenditure with the doubly labeled water (DLW) method. This approach enables accurate measurement of energy expenditure that accelerate confident decision-making.

    Trusted by Pharma and Biotech to Validate Mechanism of Action

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    Endpoints & Readouts

    What Sets Us Apart in Metabolic Biomarker Analysis

    Our clients get more than data. They get clarity, confidence, and a partner built for the unique demands of drug development.

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    35+ Years exclusively in stable isotope tracer studies

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    Experimental protocol designs and results delivered weeks faster than CROs
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    GLP-compliant, CLIA-certified, 21 CFR Part 11 validated

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    Consultative approach, with over 1,000+ studies guided from design to submission

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    Method Overview

    Why Use the Doubly Labeled Water Method?

    The DLW method is the gold standard of indirect calorimetry, validated extensively in both animals and humans.

    • Safe & non-invasive - Requires only plasma, urine, or saliva samples.
    • Non-restrictive - Ideal for patients, children, and even field studies.
    • Trusted worldwide - Proven in thousands of studies across clinical and research settings.

    With Metabolic Solutions, you get data regulators trust and timelines researchers need.

    Protocol & Technical Specifications

    How the Doubly Labeled Water Method Works

    1
    Baseline sample collection
    Plasma, saliva, or urine is obtained to determine pre-dose isotope levels.
    2
    Tracer dosing
    Subjects receive a single oral bolus of heavy water (2H218O).
    1. Adults: ~0.15 g H218O/kg body weight and 0.06 g ²H2O/kg.
    2. Children and neonates: Higher doses per kg due to faster water turnover rates.
    3
    Follow-up sampling
    Additional body fluid samples collected 1–2 weeks later.
    4
    Isotope analysis
    We measure deuterium and oxygen-18 enrichments with high sensitivity from just 15–25 µl of sample.
    5
    Energy expenditure calculation
    Output is total daily energy expenditure, derived from isotope elimination rates.

    How Researchers Use the Doubly Labeled Water Method

    We support diverse research programs, including: 

    Application Subject Type Reference  
    Musculoskeletal Health Middle-age women and men Total daily energy expenditure: OPEN Study Download
    Weight loss studies Adults Long-term effects of energy-restricted diets Download
    Total daily energy expenditure Children Energy expenditure predicts changes in body fat in children Download
    Comparisons of food frequency questionnaires Adults Accuracy of dietary assessment methods Download
    Total daily energy expenditure Small animals DLW studies in mice Download
    Field metabolic studies Animals Field metabolic rate and body size Download

    Want to Learn More?

    For procedures, validation studies, and detailed protocols, see our technical publication: Energy Expenditure using Doubly Labeled Water.

    All Analyses Are Performed In Our Certified Laboratory Environment

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    Trusted by Leaders in Metabolic Research

    From discovery to submission, we’ve earned the confidence of industry innovators through precision, speed, and scientific depth.

    We weren't just sending samples and waiting for results; we were actively sitting down with the team, discussing the limitations and variability we were seeing, and working through solutions together. It felt like they were part of our internal team.

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    Vaishaali Natarajan Insitro

    They’ve been very consistent… the sample analysis and data has always been timely and high quality.

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    Dan Tardiff CAMP4

    I think they’re extremely organized and very on top of sample management. All the interactions that I’ve had with them have been great.

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    Morganne A. Ultragenyx
    Looking for Answers?

    Frequently Asked Questions

    Is the DLW method safe for humans and animals?

    Yes. DLW uses non-radioactive stable isotopes (2H and 18O) that are completely safe, even for children, neonates, and animal studies.

    What is the typical study duration?

    The protocol generally requires baseline sampling, a single oral tracer dose, and follow-up samples collected 1–2 weeks later.

    Do you assist with study design and regulatory requirements?

    Absolutely. We provide consultation on tracer dosing, sampling protocols, and regulatory considerations, ensuring data that meets GLP and FDA/EMA standards.

    Contact Us

    Talk to our isotope experts today about designing your DLW study and getting results regulators trust
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    Metabolic Solutions, LLC.
    460 Amherst St., Nashua,
    NH 03063, USA

    Hours of Operation
    Monday – Friday
    7:30 am – 6:00 pm EST 

    Contact us

    Metabolic Solutions, LLC.
    460 Amherst St., Nashua, NH 03063, USA

    (603) 598-6960

    (603) 598-6973

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    Research: info@metsol.com

    Hours of Operation
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