Obesity ICD-10 Codes: E66 and Z68 Reference for GLP-1 PA

You’ve spent months working with your provider to get prior authorization for GLP-1 medication. Your charts are documented. You meet the BMI threshold. You’ve compiled everything your insurance company asked for. And then the request comes back, “Insufficient documentation.”

What went wrong?

Often, the problem isn’t what was documented. It’s how it was coded.

When your provider submits a prior authorization request or a claim to your insurance company, they don’t just describe your situation. They use a standardized coding system called ICD-10^[1]. These codes tell the insurance company exactly what conditions are being treated, which specific diagnoses support the medical necessity, and whether you meet their clinical criteria for approval.

For GLP-1 weight management medications, the ICD-10 codes your provider includes are often what determines whether your insurance says yes or no.

This page walks you through the main obesity and BMI codes, explains how they work together in a prior authorization request, and shows you which comorbidity codes strengthen your case. If you’re navigating the insurance process yourself or want to understand what your provider should be documenting, this is the reference you need.

Primary obesity codes (E66 category)

The E66 category is the main classification for obesity in ICD-10^[2]. Each code under E66 describes a different type or severity of obesity.

What this means for your prior authorization:

E66.01 (morbid obesity due to excess calories) is the most common code used in GLP-1 prior authorization submissions. Insurance companies recognize this code as indicating a patient with significant weight-related health concerns. However, the code alone doesn’t tell the insurance company your specific BMI, which is why the Z68 code (described below) must be paired with it.

Overweight codes

If your BMI falls between 25.0 and 29.9, you are classified as overweight rather than obese. This is coded separately:

Overweight codes are used when BMI does not meet the obesity threshold. For GLP-1 medications, an overweight code alone would not typically support a prior authorization request unless other significant comorbidities are present. That’s why documenting your actual BMI (via the Z68 code) is critical.

BMI documentation codes (Z68 series)

The Z68 series provides specific BMI range codes^[3]. These are supplemental codes, not primary diagnoses, but they are essential for prior authorization. Insurance companies use them to verify that a patient meets the BMI threshold required by their coverage policy.

When you submit a prior authorization, your provider should include both a primary obesity code (E66.x) and a corresponding BMI code from the Z68 series.

BMI codes 19 to 29 (normal to overweight range)

BMI codes 30 to 39 (obesity range)

BMI codes 40 and above (severe/morbid obesity range)

Why BMI codes matter for GLP-1 prior authorization:

Most insurance policies for GLP-1 medications require a documented BMI of 30 or higher, or 27 or higher with a significant comorbidity. The Z68 code proves this. Without it, a prior authorization request lacks concrete evidence that the patient qualifies, even if their medical records clearly show the BMI.

Think of it this way. The E66.x code says “this patient has obesity.” The Z68 code says “specifically, this patient’s BMI is 38.2.” Insurers need both pieces of information to approve coverage.

Comorbidity codes that strengthen GLP-1 prior authorization

If your BMI is between 27 and 29.9 (above normal but below the standard 30 threshold), or if you have significant weight-related health conditions, including comorbidity codes alongside your obesity and BMI codes makes a compelling case for prior authorization.

These are the most commonly documented comorbidities:

How comorbidities support your prior authorization:

If you have one or more of these conditions documented in your medical records, your provider should include the corresponding ICD-10 codes in the prior authorization submission. Insurance companies use these to determine whether the patient’s weight is creating specific health risks that medication can address.

For example, a patient with a BMI of 27.8 and documented type 2 diabetes might be denied GLP-1 coverage based on BMI alone. But with the diabetes code (E11.x) included, the insurance company sees that the patient’s weight is directly contributing to metabolic disease, making GLP-1 medication medically necessary.

How your provider uses these codes in prior authorization

When you complete an intake form with a new provider, you’re providing the raw information. Your provider translates that information into ICD-10 codes, which then go into the prior authorization request to your insurance company.

Here’s the process:

Step 1: Documentation

During your appointment or intake, your provider documents your current diagnoses, BMI, and any relevant health conditions. They review your medical history and confirm which codes apply to you.

Step 2: Code selection

Your provider selects the appropriate ICD-10 codes:

• Primary diagnosis code (E66.x for obesity or E66.3 for overweight)
• BMI documentation code (Z68.x matching your specific BMI range)
• Any relevant comorbidity codes (I10 for hypertension, E11.x for diabetes, etc.)

Step 3: Prior authorization submission

All of these codes are included in the prior authorization request submitted to your insurance company. The insurance company uses the codes to verify that you meet their clinical criteria.

Step 4: Insurance decision

The insurance company reviews the codes and determines coverage. If the prior authorization is denied, it’s often because a critical code is missing. The most common issue: the provider submitted an obesity code (E66.x) but no BMI code (Z68.x), leaving the insurance company without proof that you meet the BMI threshold.

What this means for you:

If you’re going through prior authorization, make sure your recent appointment notes include documentation of your BMI. When your provider submits the prior authorization, ask them to confirm that both the obesity code and the BMI code are included. If the request is initially denied, ask specifically whether the denial cites “insufficient documentation” of BMI. If so, a resubmission with the Z68 code often resolves it.

The cash-pay alternative: no prior authorization, no codes needed

If the prior authorization process feels like too much back-and-forth, or if you want immediate access to a provider without waiting for insurance approval, Transformation Health’s cash-pay program removes the entire process.

With cash-pay GLP-1 programs, there is no prior authorization. No insurance company to convince. No codes to navigate. You complete a free online assessment. An independent, licensed provider reviews your information and determines whether a GLP-1 medication is medically appropriate for you. If it is, you have a decision within 24-48 hours, and your medication ships as soon as your prescription is processed.

The program is all-inclusive. Your monthly fee covers your medication, medical weight loss coaching, lab work (ordered through Quest or Labcorp at no extra cost), and access to your provider. No hidden fees. No subscription locks. You can cancel anytime.

Pricing starts at $249/month for compounded semaglutide (injectable) or $279/month for oral semaglutide. Tirzepatide is $339/month. FSA and HSA accounts are accepted. You are not required to have insurance.

The tradeoff is that you pay out of pocket instead of using insurance. But for many patients, the speed, simplicity, and predictability of cash-pay makes that worthwhile.

Citations

[1] U.S. Centers for Disease Control and Prevention. “ICD-10-CM: About.” https://www.cdc.gov/nchs/icd/icd-10-cm/index.html

[2] ICD10Data. “ICD-10 Code E66: Overweight and Obesity.” https://www.icd10data.com/ICD10CM/Codes/E00-E89/E65-E68/E66-/Obesity

[3] ICD10Data. “ICD-10 Code Z68: Body Mass Index (BMI).” https://www.icd10data.com/ICD10CM/Codes/Z00-Z99/Z60-Z69/Z68-