Is Minoxidil OK to Use After Leaving the Cap Off for a Day?'

Name: Rashid

Question: I just realised I left the cap off my minoxidil for a whole day after applying it yesterday morning (I only use it once a day). Now it doesn't smell the same so I'm worried it's gone off even though it looks the same. Can I still use it?

Answer: Hi, Rashid. As you're not a Belgravia client, we don't know which specific hair loss solution you are referring to. However, we're assuming you are using a liquid solution of high strength minoxidil.

If this is the case, whether or not it is still fine to use largely depends on where the bottle was left.

As a general rule, this hair loss treatment should be kept at room temperature, away from excessive heat or humidity. Cool or room temperature environments should, therefore, be fine.

If it was in a warm environment, it is likely a bit of the alcohol contained within the formulation evaporated, but this should not be enough to cause it to go off. The smell of the hair loss product should not have changed, though if the alcohol content was slightly altered through evaporation, there is a chance it may smell less strongly of alcohol, though only by a negligible amount.

The key sign you should look for is whether any crystals have formed inside the bottle - usually at the bottom. If they have, this suggests the minoxidil has evaporated and the solution is no longer effective.

These crystals may not form straight away so, we recommend ensuring you keep the cap on when not in use - as usual - and continue to apply your minoxidil as normal, but monitor the liquid for the next few days.

Should you see any crystals form, you should dispose of the solution safely -do not simply put it in the bin. To do so you should take it to your local pharmacist or the provider you purchased the treatment from, and ask them to dispose of it responsibly for you.

They should have access to a medication take-back programme or other safe drug disposal service; these are pharmacy initiatives which aim to reduce the risk of medication potentially contaminating children, animals or the environment. There is not usually a charge for such a service.