Every price comparison in this category assumes the prices are the same kind of number. They are not. Across the 129 sellers whose price we have verified, four different billing cadences are in use, and only one of them means what a shopper reading a card assumes it means.
This is not about anyone hiding anything. Each of these cadences is disclosed somewhere, and several sellers state theirs plainly. It is about what you infer from a number on a card when the card does not repeat the cycle — and about why we keep the unit attached to every price on this site rather than flattening them all into “per month”.
Every four weeks is 13 charges a year, not 12
8 sellers bill on a four-week cycle. Four weeks is 28 days, a month averages a little over 30, and the difference compounds into one extra charge a year. The card shows the same figure either way.
Take one of them, at $279 every four weeks. Read as monthly that is $3,348 a year. Billed every four weeks it is $3,627 — $279 more, or 8.3% more than the same number read the way most people read it. Nothing on the page was untrue. The cycle simply was not the one you assumed.
You can see which sellers this applies to, and what a year costs on each cadence, in what a year of NAD⁺ actually costs. It annualizes each price under the seller’s own cycle rather than a common one, which is the only way the totals mean anything next to each other.
Per session is a price with no frequency in it at all
11 sellers price by the session, which is what an IV drip is: you pay for the appointment. There is no cycle to annualize because nobody is billing you on a schedule — you are billed when you go.
That makes a per-session price honest and incomparable at the same time. A course is rarely one session, and how many you have is a decision between you and the clinic, so any yearly figure attached to it would be our assumption about your treatment rather than their price. We show these prices with the unit on them and refuse to put them on a monthly axis; the infusion-versus-injection comparison is where the cost difference between the two routes is worth reading properly.
Per vial is a price with no time in it either
6 sellers price by the vial. A vial is a quantity, and how long it lasts depends entirely on your dose — which means the same vial price is a fortnight’s supply for one person and two months’ for another.
This is the one cadence you can convert yourself, because the arithmetic is fully determined once you know the strength, the volume and your dose. The vial calculator takes those and returns the days a vial covers and what a month costs, which turns a per-vial price into something you can hold against a monthly one. Without the dose, no conversion exists — and the units-to-milligrams conversion is where that usually falls down.
And monthly, which means what it says
The remaining 104 are billed on a roughly monthly cycle, and for those the number on the card times twelve is the year. That is the whole category of price people assume they are comparing, and it is the majority — which is exactly why the exceptions catch people. You are not scanning for a cadence, because 104 out of 129 times you did not need to.
What to do with this before you subscribe
One question settles it: how often will my card be charged, and what is the amount each time? Not what the monthly price is — the cycle and the charge. A seller on a four-week cycle will tell you, and then you can do the multiplication yourself rather than inheriting someone else’s.
It is the same class of problem as an advertised price that is not the standing rate: the figure you are shown is real, and it is answering a narrower question than the one you asked. What a year costs is the question, and the cycle is half the answer. What you agreed to when you signed up is the other half, because a cadence only matters for as long as you cannot stop it.