Most plans follow the FDA label: a BMI of 30 or above, or 27 or above with at least one weight-related condition. But the number that decides your case is not necessarily the one on the scale today. Many plans assess your highest documented BMI, and nearly all of them want it measured in a clinic rather than reported over the phone.
This is one part of getting a GLP-1 covered. For the full picture, see GLP-1 Insurance Coverage: The Complete Guide.
The standard thresholds
Coverage criteria almost always start from the FDA-approved indication for chronic weight management, which sets two entry points.
| Your BMI | What is required |
|---|---|
| 30 or above | Obesity itself is the qualifying condition. No comorbidity needed. |
| 27 to 29.9 | At least one documented weight-related condition. |
| Below 27 | Generally outside the label. Approval is rare and needs strong clinical rationale. |
Some plans set the bar higher than the label — requiring 32, or 35, or 30-with-a-comorbidity. That is legal; a plan can be more restrictive than the FDA indication, just not more permissive in a way that contradicts it.
Which BMI the plan actually uses
This is the part that catches people out, and it cuts both ways.
If you have already lost weight before the request goes in — through dieting, through a previous medication, through illness — your current BMI may sit below the threshold even though your baseline was well above it. Many plan policies assess the highest documented BMI, or the BMI at the start of treatment, precisely because a drug that works would otherwise disqualify the patient taking it.
Ask your prescriber to make sure your peak documented weight is in the record with a date attached. If your highest weight was recorded at a different practice, request those records yourself and have them added.
The reverse also applies. If your BMI has recently crossed a threshold upward, a single measurement may draw scrutiny, and a documented trend over several visits is stronger than one reading.
Measured beats self-reported, every time
A weight you gave over the phone, or one recorded from memory at intake, is weak evidence. A height and weight taken in the office and entered as vitals is what the reviewer is looking for.
This matters most at the margins. A BMI of 27.1 built from a self-reported weight invites a second look in a way that 34.2 measured in clinic does not. If you are close to a threshold, ask to be weighed at the visit and confirm the number went into the chart.
One practical note: BMI is calculated from height as well as weight, and adult heights recorded years ago are often wrong. A height that is two inches too tall can move your BMI by roughly a full point.
Where BMI is a poor measure, and what to do about it
BMI does not distinguish muscle from fat, and it performs differently across ethnic groups — several clinical bodies recommend lower thresholds for people of South Asian, East Asian and some other ancestries, because metabolic risk appears at a lower BMI.
Plan criteria rarely reflect this. If you fall into that gap, the argument has to be made explicitly by your prescriber as clinical rationale rather than assumed to be built into the policy.
If you are just below the threshold
Do not gain weight to qualify. It is a genuinely bad trade — you would be adding cardiometabolic risk to obtain a drug meant to reduce it, and a few pounds of deliberate gain is not a strategy any clinician should endorse.
Better routes exist. Check whether an older, higher documented weight is available from a previous practice. Check whether an unrecognized comorbidity is present but uncoded, which is common with sleep apnea, fatty liver disease and prediabetes. And ask your prescriber whether the plan’s policy allows an exception request on clinical grounds.
Between 27 and 29.9 you also need a documented condition, covered in whether you need a comorbidity. And the threshold is only half the picture, since the record of prior attempts is where most requests actually fail.
Frequently asked questions
Does the plan use BMI at the time of the request or my starting BMI?
It varies by policy, and it is worth reading the plan’s own criteria document rather than assuming. Many use the highest documented value. Ask for the policy in writing.
My BMI dropped below 30 on the medication. Will they stop covering it?
Renewals are usually assessed on continuation criteria — evidence the drug is working — rather than on whether you still meet the initial entry threshold. That said, some policies do reassess. Check yours before you get close.
Can I use a home scale reading?
For your own tracking, yes. For a prior authorization, the plan wants a clinical measurement.
Does body composition or a DEXA scan help?
Rarely, on its own. Most criteria are written around BMI specifically. A DEXA result can support a prescriber’s clinical argument but will not usually substitute for the threshold.
What if my height in the chart is wrong?
Ask to be re-measured. It is a two-minute fix that can change the calculated BMI meaningfully.
Do pediatric criteria work the same way?
No. Adolescent criteria use BMI percentile for age and sex rather than absolute BMI, and the coverage rules differ.
Sources
- FDA Prescribing Information, Wegovy (semaglutide) injection — accessdata.fda.gov
- FDA Prescribing Information, Zepbound (tirzepatide) injection — accessdata.fda.gov
- Named payer clinical policy bulletins — to be added