I have compiled this extensive table of drugs and supplements that affect peripheral deiodination of thyroid hormone.
NOTES:
D1 and D2 are the enzymes that generate T3 from T4.
D2 is responsible for the majority of peripheral thyroid conversion and is the primary enzyme in the central nervous system and skeletal muscle.
D1 is found in liver, thyroid, kidney and heart.
D3 is primarily responsible for T4 deactivation.
D2 increases in hypothyroidism whereas D1 and D3 decrease in hypothyroidism and increase in hyperthyroidism.
| D1 | D2 | D3 | ||
| Lithium | ↓ | ↑ | ↓ | D2 is controversial, may apply to parts of the brain; Li interferes with iodine transport in thyroid; see “Lithium” for more info |
| Carbamazepine | ↑ | |||
| Cytokines (chronic inflammation) | ↓ | ↓ | ↑ | |
| Estrogen | ↑ | ↑ | ||
| Progesterone | ↑ | ↑ | ||
| Testosterone | ↑ | |||
| Bile acids | ↑ | |||
| Stress | ↑ | ↑ | ||
| Insulin | ↑ | |||
| Vitamin D | ↓ | ↑ | Dio1 decrease has been shown in liver only | |
| Selenium | ↑ | co-factor; I’ve had good results with this brand | ||
| Chronic pain | ↑ | |||
| Somatostatin | ↓ | |||
| Growth hormone | ↑ | |||
| Iodine | ↓ | |||
| Fluoxetine (Prozac) | ↑ | |||
| T4 | ↓ | |||
| Riboflavin | ↑ | co-factor, role unclear | ||
| Cortisol | ↓ | ↑ | also decreases TSH | |
| Calorie restriction or carbohydrate restriction | ↑ | ↑ | ||
| Opioids | ↓ | |||
| Retinoic acid | ↑ | may decrease TSH; needs to be pure retinol, not beta-carotene (like this brand) | ||
| Environmental toxins | ↓ | ↓ | ||
| Xenobitoics | ↓ | ↓ | ||
| Norepinephrine | ↑ | also stimulates TRH; can be increased with L-tyrosine | ||
| Sleep deprivation | ↑ | |||
| Iron deficiency | ↑ | |||
| T3 | ↑ | use micro-doses to avoid TSH suppression(see “Ken Blanchard Protocol“) | ||
| High fat diet | ↑ | |||
| Propranolol | ↓ | |||
| Zinc | ↑ | |||
| Vitamin B12 | ↑ | |||
| Vitamin C | ↑ | due to effect on lipid preoccupation | ||
| Vitamin E | ↑ | due to effect on lipid preoccupation | ||
| Flavonoids | ↓ | especially luteolin |
This is really good, thanks for doing this. This goes on my ‘fridge!