Supplements

[Puddingym]

Does magnesium threonate have a negative effect on your thyroid medication? Are there any other supplements that affect thyroid meds. Thanks in advance.

[greygoose]

You mean affect absorption in the gut? Well, potentially all of them. Especially any kind if magnesium. Which is why it should be taken four hours away from thyroid hormone, just like iron, calcium and vit D. All others should be at least two hours away.

[Puddingym in reply to greygoose]

thanks for your reply. I take the magnesium at night before bed. Would that still cause my thyroid levels to drop? Is it a supplement I should stop taking ? Lastly, I have a thyroid test tomorrow at 9am, I am on both T4 and T3 should I take both doses in the morning? I also have a chance to get my reverse T3 tested, should I bother? Thanks so much.

[helvella Administrator Thyroid UK in reply to Puddingym]

Iron, magnesium, aluminium, calcium can all bind to levothyroxine. (These are all metallic elements which tend to be taken in relatively large quantities - at least compared to doses of levothyroxine!)

The closer together you take these substances to a dose of levothyroxine, the more likely there is to be some binding. And the more that is likely to be bound. And the precise chemical form will make a difference.

It has been shown that iron can "catch up" with levothyroxine, or vice versa, such that it isn't sufficient just for the iron or the levothyroxine to have emptied from the stomach itself. That is why, when pushed, four hours is suggested as a gap. But no-one can say three hours and fifty minutes is a problem but four hours isn't! Nor is there much clarity about iron before levothyroxine versus levothyroxine before iron. Research showed there is an issue. Research showed that even quite significant time gaps, such as two hours, do not completely avoid the issue in all people.

Once levothyroxine is bound to any of them, it makes some of the levothyroxine unavailable to be absorbed. But we can never predict its exact effect.

It isn't a matter of not taking any of them - if you need them, take them.

It is a matter of ensuring that there is a suitable gap.

Like so much of managing thyroid issues, there is enough research to indicate an issue exists. But insufficient to translate that issue into detailed, comprehensive guidance. And remember that many levothyroxine tablets actually contain magnesium stearate! And calcium phosphate used to be a reasonably common ingredient.

[Puddingym in reply to helvella]

Thank you so much for that.

[JGBH in reply to helvella]

Thank you so much for such an enlightening explanation. I take so many supplements that is is a bit of a minefield… not having enough hours in a day.

Incidentally, would it be logical in assuming such metallic supplements have a binding effect with Liothyronine as well?

[helvella Administrator Thyroid UK in reply to JGBH]

That would be, as you actually say!, an assumption.

I am NOT willing to say that is the case. But it is certainly something that is possible.

[JGBH in reply to helvella]

Thank you for replying. It is so difficult to obtain ´accurate ´ information regarding drugs interactions… Too many drugs … Should you come across any information regarding Liothyronine and interactions with other drugs, I would welcome your output, as usual. I will keep on trying to find out too..

[helvella Administrator Thyroid UK in reply to JGBH]

One of the better sites to look at is this:

DRUGBANK ONLINE

DrugBank Online is a comprehensive, free-to-access, online database containing information on drugs and drug targets. As both a bioinformatics and a cheminformatics resource, we combine detailed drug (i.e. chemical, pharmacological and pharmaceutical) data with comprehensive drug target (i.e. sequence, structure, and pathway) information. DrugBank Online is widely used by the drug industry, medicinal chemists, pharmacists, physicians, students and the general public. Because of its broad scope, comprehensive referencing, and detailed data descriptions, DrugBank is enabling major advancements across the data-driven medicine industry.

This link is to their Liothyronine page:

go.drugbank.com/drugs/DB00279

However, I've had problems registering and logging in. Am sure I managed to but no longer working!

[JGBH in reply to helvella]

Thank you so much for this information. Really appreciate it. Many people might find it helpful.

[greygoose in reply to Puddingym]

Brilliant response from helvella on the subject of supplements.

As to rT3, don't bother. It's very expensive and doesn't give you any useful information. It will tell you if your rT3 in high, but won't tell you why - and there are many, many possible causes. And only one of them has anything to do with your thyroid, and that is when the FT4 is too high.

And, in any case, it's not the rT3 itself that is a problem - it is the result of poor conversion, not the cause. It is inert and only stays in the system for a couple of hours before being converted into T2. So, not worth bothering about.

[Puddingym in reply to greygoose]

Great reply, thank you.

[greygoose in reply to Puddingym]

You're welcome.