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When you cannot get hold of it

Supply problems in this class have been constant since 2022. What to do, and the one thing not to do.

The short version

The situation

Your pharmacy cannot fill your prescription, or your private supplier has run out.

The short answer

Speak to your pharmacist first. Shortages are usually local and temporary, other pharmacies may have stock, and your prescriber has options including a different licensed drug in the same class.

The catch

This is the exact moment people buy from somewhere they would normally avoid. The MHRA seized over 2,000 unlicensed pens plus raw manufacturing ingredients in a single operation in October 2025, and issued an alert about falsified Mounjaro pens in February 2026.

This is a reference, not medical advice. Anything about your own treatment is a conversation with whoever prescribes for you.

01What to do, in order

  1. Ask your pharmacist directly. They can see supply status, know what is actually available, and do not require an appointment.
  2. Ask whether another pharmacy locally has stock. Prescriptions can often be redirected.
  3. Contact your prescriber if it looks like more than a few days. There are several licensed drugs in this class and switching is a clinical decision they can make.
  4. If you are on it for type 2 diabetes rather than weight, treat a gap as more urgent, because your glucose control depends on it.

02What a gap actually does

For weight management, appetite returns as the drug clears. How fast depends on which one you are on: a weekly drug persists for a while, a daily one does not. Missing a period of treatment is not dangerous in itself, and any weight that returns is not permanent.

For type 2 diabetes it is different, because glucose control worsens. That is a reason to press harder and sooner, and to speak to your diabetes team rather than waiting.

If you have been off it for a while, do not simply restart where you left off. Tolerance to the gut effects fades, and restarting at a previous dose can be rough. That is a conversation with your prescriber.

03The thing not to do

Why this is the risky moment

Grey-market sellers exist because of exactly this situation. Someone established on a medicine, suddenly without it, is the most motivated customer there is.

The MHRA seized more than 2,000 unlicensed weight-loss pens in October 2025, along with raw chemical ingredients, in what it described as the largest such seizure recorded anywhere. The raw ingredients are the detail that matters: somebody was manufacturing, not reselling diverted genuine stock. In February 2026 the MHRA issued a separate alert about falsified Mounjaro pens.

There is no way to verify what is in an unlicensed pen, no batch to recall if a problem emerges, and no Yellow Card coverage. A gap in treatment is recoverable. An unverified injection is a different category of risk.

The rule is unchanged: a registered UK pharmacy against a valid prescription. You can check any pharmacy's registration on the General Pharmaceutical Council register in under a minute.

04Questions worth asking

Take these to your GP, practice nurse, pharmacist or specialist team. The answers are specific to you in a way nothing on this page can be.

  1. Is this a national shortage or just this branch?
  2. Is there another licensed drug in this class I could switch to while it is unavailable?
  3. If I have been off it for a few weeks, what should I restart on?
  4. Should I be doing anything differently in the meantime?

05Common questions

What do I do if my pharmacy has no Mounjaro?

Ask the pharmacist first, since shortages are often local and short-lived and another pharmacy may have stock. If it looks like more than a few days, contact your prescriber, because there are several licensed drugs in this class and switching is an option.

Is it dangerous to miss doses?

For weight management, appetite returns and weight may follow, which is unwelcome rather than dangerous. For type 2 diabetes, glucose control worsens and a gap is more urgent, so speak to your diabetes team.

Can I buy it online while there is a shortage?

Only from a registered UK pharmacy against a valid prescription. Anything else is unlicensed product of unverifiable contents, and shortages are precisely when the grey market gets busiest. The MHRA has issued alerts about falsified pens.

Can I restart at the dose I was on?

Ask your prescriber. Tolerance to the gut side effects fades during a break, so restarting where you left off can be considerably rougher than you remember.

06Sources

  1. MHRA enforcement and falsified medicines alertsMHRA
  2. Check a pharmacy's registrationGeneral Pharmaceutical Council
  3. Medicine supply notificationsDepartment of Health and Social Care
  4. Buying medicines onlineMHRA
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