The Claim

Propylthiouracil inhibits both outer ring deiodination of reverse T3 and inner ring deiodination of T3 sulfate in human liver microsomes with similar potency, with a Ki of 0.10–0.16 μmol/L.

Source: Deiodination of thyroid hormone by human liver.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
20score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

Propylthiouracil reduces the breakdown of reverse T3 and T3 sulfate in human liver tissue samples at similar concentrations, with an inhibition constant between 0.10 and 0.16 micromoles per liter.

See the scientific wording

Propylthiouracil inhibits both outer ring deiodination of reverse T3 and inner ring deiodination of T3 sulfate in human liver microsomes with similar potency, with a Ki of 0.10–0.16 μmol/L.

Why this might work

A single enzyme in the liver removes iodine atoms from two different thyroid hormone molecules — reverse T3 and T3 sulfate — using the same active site. Propylthiouracil blocks this enzyme by binding to it in a way that prevents the enzyme from using its essential helper molecule, causing both hormone breakdown processes to stop at the same rate.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Deiodination of thyroid hormone by human liver.

    The study found that the drug propylthiouracil stops two different thyroid hormone breakdown processes in the liver at the same strength, meaning it likely targets the same enzyme for both. This matches exactly what the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.