Why Retatrutide Listings Quote Price Before Customs Duties

Some retatrutide listings quote price before customs or import duties are added because the seller does not control the three inputs that set those charges: your destination country, the tariff code the shipper declares, and the declared value of the parcel. Duty, import VAT or GST, and the courier’s brokerage fee are assessed at the border and billed to the importer of record, which is the buyer. A catalogue price is therefore a product price, not a landed price, and the two can differ by double digits on the same order.

What a quoted retatrutide price normally covers

A listing price covers the vial and its contents, usually packaging, and sometimes domestic outbound shipping. It does not cover anything a customs authority or a courier assesses after the parcel enters your country. Those charges attach to the shipment, not to the product line, so they cannot be printed on a product page that serves buyers in twenty jurisdictions.

The gap matters because the charges are not trivial rounding. They are a percentage of declared value plus, in most courier programs, a fixed disbursement or advancement fee for fronting the money to the customs authority. One is proportional and one is not, and they behave differently as order size changes. A fuller breakdown of what a complete quote itemises is worth checking against any listing that shows a single number with no fee line.

How much does import duty change the cost per mg?

Base prices below come from the HEEZ catalog as of September 2026: a 10 mg vial at $100 and a 20 mg vial at $195. Base cost per mg is the vial price divided by vial mg, so $100 ÷ 10 mg = $10.00/mg and $195 ÷ 20 mg = $9.75/mg. Each duty column applies an ad valorem rate to the vial price before dividing: landed $/mg = (vial price × (1 + rate)) ÷ vial mg.

Ad valorem rate (%)	10 mg vial, landed ($)	10 mg, cost per mg ($)	20 mg vial, landed ($)	20 mg, cost per mg ($)	Gap per mg ($)
0	100.00	10.00	195.00	9.75	0.25
5	105.00	10.50	204.75	10.24	0.26
10	110.00	11.00	214.50	10.73	0.28
20	120.00	12.00	234.00	11.70	0.30

Base prices as of September 2026 from the HEEZ catalog; duty rates are illustrative inputs you substitute with the rate your own jurisdiction applies, not published tariff figures. Every landed figure is the arithmetic shown above.

Read the last column first. A proportional duty does not change which format is cheaper per mg, because multiplying both prices by the same factor preserves their ratio: the 20 mg vial stays 2.5% cheaper per mg at every rate. What grows is the absolute gap, from $0.25/mg to $0.30/mg across a 20-point swing in rate. If you already understand how the per-mg figure is calculated, the duty column simply rescales it.

Does a flat brokerage fee change which vial size wins?

A fixed per-shipment charge behaves differently, and this is where the ranking can move. Using $30 as an example input for a courier’s combined brokerage and disbursement charge on a single-vial shipment, the fee is spread over whatever mg that shipment contains:

• 10 mg vial: ($100 + $30) ÷ 10 mg = $13.00/mg
• 20 mg vial: ($195 + $30) ÷ 20 mg = $11.25/mg

The per-mg gap widens from $0.25 to $1.75, a sevenfold increase, purely because the fixed fee is diluted across twice as much material in the larger vial. Fixed charges punish small orders in a way percentage duties do not, which is the practical reason a duty-exclusive quote understates small-order cost more than large-order cost. This is one of several reasons prices differ between listings that look identical on the product line.

Scale it to a research quantity. The phase 2 obesity trial dosed 338 adults once weekly for 48 weeks at maintenance doses up to 12 mg (the 2023 NEJM phase 2 retatrutide report). A schedule matching that top arm’s 12 mg weekly across 48 weeks consumes 12 × 48 = 576 mg, an upper bound since that arm started at 2 mg and escalated. At 20 mg per vial, 576 ÷ 20 = 28.8, so 29 vials, and 29 × $195 = $5,655 as of September 2026 from the HEEZ catalog. A 10% duty on that declared value adds $565.50, taking the order to $6,220.50. The fee line that looked like a footnote on a single vial now exceeds the price of two vials ($390 at the same catalog rate).

Why can’t the seller just quote a duty-inclusive price?

Duty is calculated on a declared tariff classification, and retatrutide has no approved finished-drug classification to declare. The compound remains investigational: Lilly’s pre-approval expanded access protocol for LY3437943 is open only to adults with a BMI of at least 35 kg/m² and at least two serious or life-threatening obesity-related complications who are refractory to approved therapy (expanded access record NCT07629401). The registrational program is still running, with four phase 3 studies enrolling more than 5,800 participants on once-weekly subcutaneous retatrutide versus placebo (the 2026 TRIUMPH trial design paper).

Without an approved product code, shipments move under general chemical or research-reagent classifications, and which one a broker selects changes the rate. A seller quoting a duty-inclusive number for every destination would be guaranteeing a figure set by a third party after the parcel leaves. Most decline, and quote the product line alone. A listing that publishes a flat catalogue price, such as the vial pages at heezresearch.com/product/retatrutide/, is quoting that product line only; anything assessed at the border sits outside it. All of this concerns research-use-only material.

DDP or DAP: which one is the listing using?

Two shipping terms decide who pays, and the difference is the whole question:

• DDP (delivered duty paid) means the seller has prepaid duty and import taxes. The quoted price is the landed price, and no courier invoice follows.
• DAP (delivered at place) means the seller delivers to your address but duty and taxes are yours. The courier collects before release, often by SMS or email, sometimes days after delivery was promised.

Most peptide listings that quote a bare per-vial price are operating DAP without saying so. A listing is DDP only if it says so in words on the checkout or shipping page; silence defaults to the buyer paying.

What to check before treating a quote as final

Five checks, each answerable from the listing itself or a single support message:

1. Does the shipping page use the phrase “duties and taxes included,” or only “free shipping”? The second phrase covers freight and nothing else.
2. What value will be declared on the commercial invoice? Duty is a percentage of that figure, not of what you paid, and an undervalued declaration shifts risk to you as importer of record.
3. Is there a per-shipment handling or advancement fee separate from duty? Apply it with the flat-fee math above, not the percentage math.
4. Does consolidating into fewer, larger vials reduce the number of shipments? At $195 per 20 mg vial as of September 2026, one shipment of 29 vials carries one fixed fee; five shipments carry five.
5. Does the seller reship or refund if a parcel is seized, and is that stated in writing rather than implied in a chat reply?

The declared-value question is the one buyers skip most often. That single figure sets the duty base, caps the carrier’s insurance liability, and determines penalty exposure if a customs authority disputes it, so a seller who will not state it in advance has told you the landed cost is unknowable before the parcel ships.