I've been taking it for 9 years with no problems. I take it just as Dizzyribs does for the best effect. I would check out other possible reasons for the problem you're experiencing.
Good Morning Saturday 6th June 2026
I’ve been taking a low dose of Levothyroxine for an underactive thyroid for less than a week now and I have noticed that I have an awful taste in my mouth. My husband tells me that my breath isn’t the sweetest! Has anyone else experienced this?
I've been taking it for 9 years with no problems. I take it just as Dizzyribs does for the best effect. I would check out other possible reasons for the problem you're experiencing.
TerriBull
I take quite a high dose of 150 mcg Regarding absorption it's quite important, as pointed out up thread, to take Thyroxine on not only an empty stomach, and to leave at least an hour after coffee, not sure about tea. Lately I've been taking mine when I take that first trip to the bathroom, probably about 3 am. My last meal would usually be around 7 pm. Last coffee not later than mid afternoon. First coffee 7am I didn't always pay heed to this when I first started taking them.
Exactly what I do, So much easier to get the timing right. I do suffer with a vvery dry mouth, but can't say if that is a side affect of the Levothyroxine. I have been taking 75mg for 10 years now.
I didn’t know all that stuff about how to take it. I’m on 75mg and take it with my breakfast - fruit and a cup of tea. My TSH is ok so it must be working. Maybe if I followed the rules I could be on a lower dose but would that matter? The reason I take it at breakfast is that it’s easy to remember and I take my other medication at the same time and my vit D. I guess it’s ok ?
Thank you all for replying. I’m taking it as instructed, and like some of you when I get up to go to the loo at about 6 o’clock. I don’t normally have breakfast but found it was causing nausea, so I’m now having some toast when I get up. I spoke to a pharmacist today and he told me that it’s not likely to be the Levothyroxine and doesn’t feel that my Underactive thyroid is causing it. I am due to go to the dentist next week and hopefully they can shed some light on it. The taste (and smell) came on suddenly and is now very strong and so I’m very conscious of it, so hope it can be resolved quickly. In the meantime I’m going to try drinking lots of ginger tea.
I take my thyroxine in the morning, but didn’t know about the 30 minute gap before breakfast. My levels seem to be ok, though, so I’ll just carry on doing what I do now.
Pittcity
I don't think it's the levothyroxine causing the bad breath, it's probably the hypothyroidism.
It's a autoimmune disease and makes me more prone to dry mouth, sore throats and coughs.
The tablets should improve the situation but you need to speak to your GP if it doesn't.
I have been on this medication for more than 30 years. My experience is the same as Pittycity's. Also no problems with bad breath.
Dontcallmelove
Thank you for replies so far. It’s not a known side effect, but some people have reported having a dry mouth, mine isn’t. The best description is metallic like, but not like blood metallic if that makes sense? I don’t have a sense of taste so it’s difficult to be more descriptive. Unfortunately I can’t get to a pharmacist and we only have a dispensary at our surgery with the dispensers knowing very little about individual medication.
Dispensing is not possible unless there is a supervising pharmacist. They may not be physically present, although all prescriptions must be checked by at least ACT level (pharmacy technician grade) who is knowledgeable. My dispensary has an online pharmacist who is often on screen for help, so do ask if you need to.
Google says: It is crucial to take it on an empty stomach, usually 30-60 minutes before breakfast.
AI says:
[it] can cause dry mouth (xerostomia) as a side effect, although ..not ..most common reaction. ....can lead to a dry, sticky feeling in the mouth, difficulty swallowing, and increased dental sensitivity.
and:
[it]can cause a metallic taste in the mouth, ...not ..common, side effect .. this taste distortion (dysgeusia) also frequently stems from underlying thyroid conditions or during the initial treatment phase. ...typically improves significantly within three to six months
A metallic taste can be caused by other medications, supplements, or dental issues. If you experience a persistent or bothersome metallic taste, ..discuss this with your healthcare provider to rule out other causes/ adjust your treatment.
So you are not alone - hope that helps
Thank you FranP, that is helpful. Over the past six months I have been prescribed a number of medications and have ended up with a lot of the side effects, including eye drops that make your eyelashes grow, although this is more common in people of Japanese origin, which I’m not! My GP refused to believe that I had symptoms of an underactive thyroid and initially wouldn’t send me for a blood test. Even when it came back positive for Hashimoto’s he didn’t prescribe anything for 3 months. I think that the thyroid problem has caused the awful taste and it may go after I’ve been on the Levothyroxine for a bit longer. I’m seeing the dentist on Tuesday so hopefully gum disease will be eliminated.
Just wanted to update, in case someone reads this in the future! Dentist confirmed no oral issues. Pharmacist says very unlikely to be the Levothyroxine especially as I’m a low dose. The taste (and smell!) have gone so I don’t feel I can go back to my gp about it but will do if it happens again.
Just a thought,but you haven't got a "nervy " tummy have you ?
My mother used to say that my breath smelt at times - sometimes it was my period which I've noticed on other people and sometimes my IBS .
Years ago ,I knew a lady who existed on one protein bar all day to keep slim and only ate in the evenings.
Her breath was foul - so foul that other people complained about it.
So sometimes I attribute unpleasant breath to diet and /or dieting .
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