Weight loss injection subscription or pay monthly: which costs less

What a tie-in plan is

A subscription plan for a weight loss medicine is a fixed-term contract, usually 3, 6 or 12 months, under which a pharmacy supplies one pen or one month of tablets at a set interval and takes payment by card or direct debit each cycle. Some plans take the full sum up front. Others bill monthly but charge an exit fee or the discount back if you leave early.

A pay-monthly arrangement is a series of separate orders. You place one, the prescriber approves it, you pay, and the pen arrives. Nothing obliges you to order again. The Dose Club does not advise 3, 6 or 12 month plans for these medicines, and this page sets out why.

The price case

Every price GLP Index recorded on 21 October 2026 was a pay-monthly price, and the cheapest of them undercut anything a tie-in has to offer. For Mounjaro 5 mg the cheapest ongoing price was £125.00 at Curate (GPhC 9012920) with code NEWMONJ. The median across 80 pharmacies was £179.00. For Wegovy 1 mg the cheapest ongoing price was £79.95 at Novavie (GPhC 9012156), against a median of £119.99.

A plan is priced by one pharmacy. If the pharmacy sits at the median, a 12 month Mounjaro 5 mg plan costs £2,148.00 against £1,500.00 for twelve pay-monthly pens at the cheapest pharmacy, a difference of £648.00. A plan discount has to close a gap of £54.00 a month before it saves you anything against the cheapest pay-monthly pen.

The second cost is lost flexibility. Prices move. A pharmacy that is cheapest this month may not be next month, and a new entrant may undercut everyone. On pay monthly you can follow the cheapest price. On a plan you cannot.

The continuity argument

Pharmacies sell plans on continuity: one prescriber, one record, no gap in supply. The argument fails because a pay-monthly pharmacy offers the same continuity for as long as you want it. You can order from the same pharmacy for 12 months, keep the same prescriber record and the same delivery pattern, and leave at any point. The plan adds a lock, not a service.

The switching pharmacy guide covers what happens to your dose and history when you do move.

Who the rules protect

The Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 apply across the UK to contracts made online or by phone. Regulation 30 gives a 14-day cancellation period. For a service contract it runs from the day the contract is entered into. For goods it runs from the day the goods come into your physical possession. A medicine plan mixes both: the prescribing service and the supply of pens.

Regulation 31 extends the period if the trader fails to tell you about the right to cancel. If the information arrives late but within 12 months, you get 14 days from the day you receive it. If it never arrives, the period ends 12 months after it would otherwise have ended.

Regulation 34 requires a refund within 14 days of the trader being told you are cancelling, or 14 days from receiving the goods back where goods have been sent. Regulation 36 lets a trader charge for the part of a service supplied before cancellation if you expressly asked for it to begin during the cooling off period. Regulation 28 removes the right to return sealed goods that are not suitable for return for health protection or hygiene reasons once unsealed. An opened pen falls into this category. The regulations also apply in Northern Ireland.

Steps before you sign any plan

1. Price the same medicine and dose on the pay-monthly table for your medicine. Note the cheapest ongoing price and the median.
2. Divide the plan's total by the number of months. If the result is above the cheapest ongoing price, the plan costs you money from month one.
3. Find the cancellation clause. Check whether the pharmacy takes the full sum up front, whether early exit returns unused months, and whether any discount is clawed back.
4. Check the pharmacy's GPhC number on the GPhC register.
5. If you still sign, send any cancellation in writing inside 14 days and keep the email. The 14 days run from the contract date for the service element.

Small print to read

Look for an auto-renewal clause that rolls a 3 month plan into another 3 months unless you cancel by a set date. Look for a price review clause that lets the pharmacy raise the monthly rate during the term. Look for a dose change clause: some plans price one dose, and a prescriber decision to move you up triggers a new, higher plan. Look for a delivery clause making express delivery compulsory. Look for a minimum notice period for cancellation after the cooling off period, which can be 30 days or a full billing cycle.

Mistakes that cost money

Paying 6 months up front to lock in a first order price. The first order price is a one-off at most pharmacies and the plan rate is the ongoing one. Treating the discount as a saving against the median rather than against the cheapest pay-monthly pharmacy. Missing the 14-day window because the first pen arrived on day 10 and the cancellation clock on the service started on day one. Forgetting to cancel a direct debit after the term ends.

Where the figures come from

Prices are from the GLP Index export of 21 October 2026. Cancellation rules are from regulations 28, 30, 31, 34 and 36 of the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 on legislation.gov.uk. The worked plan examples use the median ongoing price as the plan rate because plans are priced by one pharmacy, and GLP Index does not record plan prices separately.