A 500mg and a 1000mg NAD+ product deliver the same dose per injection, usually 50mg. The number on the label tells you how many doses you get, not how strong each one is. A 500mg pen cartridge gives ten doses; a 1000mg vial gives twenty. The real choice is between a pen and a syringe, and how long you want to commit for.
This comparison is for adults about to buy their first NAD+ kit in the UK and unsure whether to start small or go straight to a larger supply. It sets the three starter options side by side: what is in each box, how long each lasts on the standard protocol, what each dose costs, and who each one suits.
Educational content, not medical advice. NAD+ is not intended to diagnose, treat, cure or prevent any disease. Speak to a licensed prescriber before starting any injectable protocol, especially if you are pregnant or breastfeeding, have active or historic cancer, or take regular medication.
500mg or 1000mg: what the numbers actually mean
The milligram figure on an NAD+ cartridge or vial is the total amount of NAD+ inside it. It is not the dose. You take a small, measured volume from it each time, and that volume holds your dose.
Our two formats are both pre-mixed, so there is nothing to reconstitute:
- Pen cartridge: 500mg of NAD+ in 3ml, about 167mg per ml.
- Vial: 1000mg of NAD+ in 5ml, 200mg per ml.
The UK at-home market has settled on 50mg per injection as the reference dose, whichever format you use. On the pen, that is 0.3ml, or 30 clicks on the dial. With a vial and a U-100 insulin syringe, it is 0.25ml, or 25 units. The concentrations differ slightly, so the volumes differ, but the NAD+ reaching you is the same.
So a 1000mg vial is not a "stronger" option than a 500mg cartridge. It is a larger supply. Think of it as the difference between a small and a large bottle of the same thing, not between two strengths. The full protocol, including the optional gentler 25mg start, is in the NAD+ injection dosage guide.
The three ways to start
If you have never used NAD+ before, there are three kits that contain everything you need for your first injection. All three, plus refills and the replacement pen, are in the NAD+ range.
NAD+ Trial Kit · 500mg
The smallest way in. One refillable auto-injector pen, one 500mg cartridge, ten micro-needles, ten wipes, a sharps bin and a quick-start guide, packed in a zip carry case. Ten doses of 50mg.
NAD+ Discovery Kit · 2 × 500mg
The same pen with two 500mg cartridges, twenty micro-needles, twenty wipes, a sharps bin and a quick-start guide, in a rigid presentation box. Twenty doses, 1000mg of NAD+ in total.
NAD+ Injection Kit · 2 × 1000mg
No pen. Two sealed 1000mg vials, forty micro-needles, forty wipes, a sharps bin and a quick-start guide, also in a rigid box. Forty doses, 2000mg of NAD+ in total, measured with an insulin-style syringe.
Side by side: contents, duration and cost per dose
Prices below were checked on 14 October 2026. Delivery is free across the UK on all three.
| Kit | NAD+ in the box | 50mg doses | Lasts about | Device | Price | Per dose |
|---|---|---|---|---|---|---|
| Trial Kit | 1 × 500mg cartridge | 10 | 2.5 weeks | Pen included | £175 | £17.50 |
| Discovery Kit | 2 × 500mg cartridges | 20 | 5 weeks | Pen included | £279 | £13.95 |
| Injection Kit | 2 × 1000mg vials | 40 | 10 weeks | Syringe | £279 | £6.98 |
Two things stand out. First, the per-dose cost of the two pen kits includes the pen itself, which you keep and reuse; a pen bought alone is £95. Second, the vial kit gives twice the NAD+ of the Discovery Kit for the same price, because it carries no device. That is the trade: you pay for the pen in convenience and precision, or you save by measuring each dose yourself.
How long each kit lasts on the standard protocol
Durations in the table assume the reference rhythm: one 50mg injection a day on days 1 to 3, then every other day. That is three to four injections a week, or 150 to 200mg.
- Trial Kit, 10 doses: the three loading days plus seven alternate-day doses takes you to roughly day 17.
- Discovery Kit, 20 doses: about five weeks, which covers the loading phase and the first full month.
- Injection Kit, 40 doses: about ten weeks at the same rhythm, and longer if you move to the twice-weekly maintenance rhythm (100mg a week) after the first month.
How long a kit lasts matters more than it first seems. Most people describe changes in energy and recovery as gradual, and the evidence base for NAD+ is still built mostly on short studies of blood levels rather than long outcome trials. A supply that only covers two weeks will tell you whether you tolerate injections and how the routine fits your day. It is less likely to tell you how you feel after a settled month.
Pen or syringe: the decision underneath the milligrams
Because the dose is the same, the format is the real decision. Both deliver NAD+ under the skin through a 32G, 6mm micro-needle, and both bypass digestion entirely. The step-by-step for each is in how to inject NAD+ at home.
Why people choose the pen
- Click-stop dosing. You turn the dial to 30 clicks and it stops there. Nothing to read against a scale.
- Fewer steps. Attach a fresh needle, dial, inject. No drawing liquid from a vial.
- Travel. A pen with a loaded cartridge fits a washbag; the Trial Kit comes in its own zip case.
- First-timer confidence. If you have never injected yourself, a pen removes most of the things that can go wrong.
Why people choose vials
- Lowest cost per dose. Roughly half the per-dose cost of the pen kits.
- Longer supply in one order. Forty doses means fewer reorders and about ten weeks between boxes.
- Flexible measuring. Adjusting by a few units is simple when you read a syringe, which suits people working with a prescriber on a non-standard dose.
The trade-off is technique. Drawing a dose means cleaning the vial top, matching air to volume, and reading the syringe at eye level. It is not difficult, and it becomes routine quickly, but it is a skill the pen does not ask of you.
Which kit suits you
There is no single right answer, but most first-time buyers fall into one of three groups.
- You want to find out whether NAD+ suits you before committing: the NAD+ Trial Kit. Ten doses, the full pen system, the lowest outlay. You keep the pen if you continue.
- You have decided to try a proper first month and want it to be simple: the NAD+ Discovery Kit. It covers the loading phase and a settled month with the pen, and the per-dose cost is lower than the Trial Kit.
- You are comfortable with a syringe, or have injected before, and want value: the NAD+ Injection Kit, 2 × 1000mg. About ten weeks of doses at the lowest cost per dose we offer.
Whichever you choose, the same cautions apply. NAD+ injections are for adults only, and they are not suitable during pregnancy or breastfeeding, with active or historic cancer, atrial fibrillation, immunosuppression or a transplant, or Lyme disease. Mild flushing, nausea or a small bump at the injection site are the common early effects; our guide to NAD+ side effects explains what is normal and when to stop.
After your first kit
If you started with a pen kit, you do not need to buy the pen again. The Pen Refill Kit brings two 500mg cartridges with needles, wipes and a sharps bin, and comes in one, two or three month supplies from £285. A single 500mg cartridge is £149 if you only need to top up. Subscriptions can be paused or cancelled at any time.
If you started with vials and found the syringe routine awkward, moving to the pen later is straightforward: the dose stays at 50mg, only the volume changes from 25 units on a syringe to 30 clicks on the pen dial. The dosage calculator converts any dose for either device, and the complete UK guide to NAD+ injections covers the wider picture if you are still deciding whether to start at all.
Frequently asked questions
Is 1000mg of NAD+ stronger than 500mg?
No. The figure is the total amount in the cartridge or vial, not the dose. Both formats are used to give 50mg per injection. A 1000mg vial simply holds twenty doses instead of ten.
How many doses are in a 500mg NAD+ cartridge?
Ten doses of 50mg. Each dose is 0.3ml, which is 30 clicks on the pen dial. At the standard rhythm, one cartridge lasts about two and a half weeks.
How many units is 50mg from a 1000mg vial?
25 units on a U-100 insulin syringe, which is 0.25ml. The vial holds 1000mg in 5ml, so every 5 units contains 10mg of NAD+.
Which NAD+ kit is cheapest per dose?
The Injection Kit with two 1000mg vials, at about £7 per 50mg dose. The pen kits cost more per dose because they include the reusable auto-injector pen.
Can I start with the Trial Kit and buy refills later?
Yes. The Trial Kit includes the pen, so when it runs out you can continue with a Pen Refill Kit or a single cartridge without buying another pen.
Is a pen or a syringe better for beginners?
Most first-timers find the pen easier because the dial clicks to the dose and there is nothing to draw up. Vials suit people who are comfortable reading a syringe and want the lowest cost per dose.
Sources
- Massudi H et al. Age-associated changes in oxidative stress and NAD+ metabolism in human tissue. PLoS ONE, 2012.
- Grant R et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Frontiers in Aging Neuroscience, 2019.
- Covarrubias AJ et al. NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 2021.
