Why cost-per-pound is the honest apples-to-apples metric

Monthly drug sticker price is misleading because a cheaper drug that delivers less weight loss is not actually cheaper. A $1,349/month Wegovy pen that produces 35 lb of loss over 12 months costs $462/lb. A $299/month compounded semaglutide that produces 22 lb of loss (real-world compounded response is often lower than trial mean because of dose interruptions and variable potency) costs $163/lb. The ranking can invert when you weight for efficacy, not just sticker.

This calculator runs the arithmetic across the six access paths most patients actually face in 2026 and lets you plug your own response to compare.

The reference numbers from the trials

Mean weight loss on top dose, converted to absolute pounds for a 225 lb starting weight:

Tirzepatide 15 mg (SURMOUNT-1, 72 weeks): 22.5% TBWL = ~50 lb.
Semaglutide 2.4 mg (STEP 1, 68 weeks): 14.9% TBWL = ~34 lb.
Liraglutide 3.0 mg (SCALE, 56 weeks): 8% TBWL = ~18 lb.
Placebo / lifestyle (STEP 1 control): 2.4% TBWL = ~5 lb.

Cost-per-pound at 12 months on each path

Assume 35 lb lost over 12 months (a plausible response at month 12 on tirzepatide 10–15 mg or semaglutide 2.4 mg):

Wegovy insured + savings card ($50/mo × 12): $600 / 35 lb = $17/lb. Outstanding value if you have coverage.
Zepbound insured + card ($50/mo): $17/lb. Same math.
LillyDirect Zepbound vial ($499/mo): $5,988 / 35 lb = $171/lb.
NovoCare Wegovy vial ($499/mo): $171/lb.
Compounded telehealth ($299/mo): $3,588 / 35 lb = $103/lb — if response matches branded, which is the uncertain assumption.
Wegovy cash list ($1,349/mo): $16,188 / 35 lb = $463/lb. Unreasonable for most households.

How cost-per-pound compares to the alternatives

Put GLP-1 pricing in context:

Bariatric surgery (sleeve gastrectomy): $15,000–$25,000 out-of-pocket (insurance often covers for BMI ≥ 40 or ≥ 35 with comorbidity). Produces 25–30% TBWL over 2 years with good regain resistance. At 70 lb lost: $215–$360/lb. Note that surgery produces different long-term metabolic outcomes — not a strict price comparison.
WW (Weight Watchers) / Noom: $25–$55/month, ~5% TBWL mean at 12 months = ~11 lb. $27–$60/lb, but response distribution is bimodal — most subscribers lose less than 5 lb.
Intensive lifestyle intervention (Diabetes Prevention Program): free to low-cost through many employers and Medicare; ~7% TBWL at 12 months = ~16 lb. Best “cost-per-pound” of any intervention, but adherence is the bottleneck.
Phentermine-topiramate (Qsymia): ~$100–$150/month cash, 9–10% TBWL. ~$120/lb over 12 months.

The “cost per durable pound” caveat

The metric above is cost per pound during treatment. GLP-1 weight loss is largely durable while on the drug and largely reversible when stopped (STEP 4: ~2/3 regain within 12 months). If you stop after 12 months, effective cost-per-pound-maintained-at-year-3 is much higher. Conversely, bariatric surgery’s one-time cost amortizes over decades of maintained loss. A more rigorous metric is dollars per QALY or dollars per year of obesity-related comorbidity avoided — ICER estimated semaglutide 2.4 mg at roughly $237,000 per QALY gained in 2022, above typical willingness-to-pay thresholds (~$150K); tirzepatide is more cost-effective per SURMOUNT-1 efficacy.

Cost-per-pound over time: why the number moves

The single biggest mistake patients make is evaluating cost-per-pound at month 3 and panicking. At month 3 on tirzepatide 5 mg titration, a patient has typically lost 8–12 lb and spent ~$1,500–$5,900 depending on path — a headline cost-per-pound of $125 to $740/lb. At month 12 the denominator grows to 35–50 lb while the numerator grew only proportionally, so cost-per-pound collapses. A worked example:

Month 3, LillyDirect: $499 × 3 = $1,497 spent; 10 lb lost; $150/lb.
Month 6: $2,994 spent; 22 lb lost; $136/lb.
Month 12: $5,988 spent; 40 lb lost; $150/lb.
Month 18 (nadir): $8,982 spent; 50 lb lost; $180/lb.
Month 24 (1 year maintenance): $11,976 spent; 48 lb net (slight regain on maintenance dose); $250/lb.

Cost-per-pound bottoms out around month 9–12 and climbs again as you pay for maintenance without new loss. This is the inverse of bariatric surgery’s economics, where the ratio improves indefinitely as the one-time cost amortizes. It is why endocrinologists increasingly discuss GLP-1 as a chronic therapy priced like an antihypertensive rather than a weight-loss intervention priced like a course of antibiotics.

Tirzepatide vs semaglutide: the efficacy-adjusted gap

SURMOUNT-1 showed 22.5% TBWL on tirzepatide 15 mg at 72 weeks vs STEP 1’s 14.9% TBWL on semaglutide 2.4 mg at 68 weeks. The SURMOUNT-5 head-to-head (Aronne et al., 2025) confirmed tirzepatide’s superiority at 72 weeks: 20.2% TBWL vs 13.7%. At a 225 lb baseline, that is 45 lb vs 31 lb — a 14-lb absolute gap. At equal monthly pricing ($499 LillyDirect vs $499 NovoCare), tirzepatide is unambiguously the better cost-per-pound buy: $199/lb vs $290/lb. The only reasons to choose semaglutide on cost are: (a) your insurance covers Wegovy but not Zepbound, (b) your prescriber cannot get Zepbound prior auth, or (c) you tolerate semaglutide meaningfully better. See the Wegovy vs Zepbound comparison.

SELECT and the “non-weight” value

The SELECT trial (Lincoff et al., NEJM 2023; N=17,604 adults with pre-existing CV disease and overweight/obesity, no T2D) showed a 20% reduction in 3-point MACE (cardiovascular death, non-fatal MI, non-fatal stroke) over ~40 months on semaglutide 2.4 mg. The absolute risk reduction was 1.5 percentage points over 40 months — number needed to treat ~67 to prevent one MACE event. If you are in the SELECT population, the cost-per-pound framing understates the value proposition because the drug is also buying you cardiovascular risk reduction independent of weight loss. Medicare’s March 2024 coverage expansion for semaglutide in this cohort was justified on SELECT, not STEP. For patients with pre-existing CV disease, the relevant metric is not cost-per-pound but cost per MACE avoided, which CMS estimated at ~$125,000 — inside typical willingness-to-pay.

Levers you control

Prior authorization: a $50 copay vs a $499 cash path is the single largest variable. See the prior auth guide.
Drug choice: tirzepatide produces ~50% more TBWL than semaglutide. Better “per dollar” even at the same monthly price.
Dose optimization: some patients plateau well at 5 mg tirzepatide or 1 mg semaglutide. Lower dose = lower list / LillyDirect price.
Duration: the first 6 months produce the bulk of the TBWL curve. Cost-per-pound improves dramatically between months 3 and 12 as the denominator grows. After month 18, you are paying maintenance.
HSA/FSA: reduces effective cost ~25–30% for most households. Calculate it.

FAQ

What is a “good” cost per pound?

Below $200/lb is excellent (insured path, good response). $200–$500/lb is typical for self-pay. Above $500/lb means something is off — either price (cash list) or response (low TBWL). Troubleshoot before continuing.

Is bariatric surgery cheaper long term?

Often yes if you can access it and amortize over 10+ years of maintained loss. The GLP-1 economics work best when insurance-covered or when you need only 10–20% TBWL and can taper to maintenance dose. See the maintenance dose tool.

Why is compounded sometimes $160/lb when the monthly is $299?

Because cost-per-pound depends on both price and response. If compounded potency matches branded and you get 35 lb in 12 months, the ratio is favorable. If potency is variable and you get only 20 lb, compounded cost-per-pound climbs to $179. Response variance is real.

Should I optimize for cost-per-pound or for total out-of-pocket?

Both. Total OOP is the cash flow you have to survive; cost-per-pound is the efficiency of the spend. A patient who can afford $600/mo but not $1,300/mo will pick the former even if it’s a worse cost-per-pound — cash flow beats efficiency.

Does this include the downstream healthcare savings?

No. Preventing T2D avoids roughly $12,000/year in complication management; sleep-apnea CPAP elimination saves ~$1,000/year; BP med reduction ~$500/year. See the health savings tool for the offsetting math.

How does insurance coverage change the calculation?

It dominates the calculation. A Wegovy prescription covered by commercial insurance with the Novo manufacturer copay card tops out at $25–$50/month for most plans. Zepbound with the Lilly savings card caps at $25–$550/month depending on coverage; patients with commercial coverage hit $25–$50 in most cases. If you are in either bracket, your cost-per-pound drops to $15–$20 — roughly 10x better than any cash path. This is why prior auth persistence matters more than drug choice. See the prior auth likelihood tool.

What about Medicare?

Medicare Part D does not cover GLP-1s for weight loss (a 2003 statutory exclusion on “anorexiants”). It does cover Ozempic/Mounjaro for T2D and, as of March 2024, semaglutide 2.4 mg (Wegovy) for adults with established CVD and overweight/obesity under the SELECT indication. The Treat and Reduce Obesity Act (TROA), pending in Congress as of 2026, would overturn the exclusion; until it passes, most Medicare patients pay cash or use manufacturer programs.

Does dose-splitting improve cost-per-pound?

Only for patients who do well at submaximal doses. Some patients plateau at tirzepatide 5 mg (15.0% TBWL in SURMOUNT-1 vs 22.5% on 15 mg) and save 50%+ by staying there. Others need 15 mg to hit their goal — pushing down to save money would leave loss on the table. Do not dose-split as a cost strategy without clinical conversation; the evidence is for whole-vial dosing as pharmacy-compounded.

Cost per pound lost on GLP-1

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