The impact of steroid use on thyroid production

The impact of steroid use on thyroid production

Something that we rarely discuss in the bodybuilding community is the impact AAS use has on thyroid function. Is it positive? Is it detrimental?

In this article, I will be looking at some of the data regarding the interaction between AAS and endogenous thyroid hormones, and explain why using low doses of exogenous thyroid hormones during an AAS cycle may be a good idea…

The impact of AAS on thyroid hormone production

AAS have a complex relationship with the regulation of thyroid hormones in the body, and their effects can be quite varied. When the body is exposed to AAS, several physiological changes occur that can impact the secretion and conversion of thyroid hormones.

One of the ways in which AAS can impact thyroid hormones is by suppressing the secretion of thyroid-stimulating hormone (TSH) from the pituitary gland. TSH is the primary stimulus for the production and release of thyroid hormones, triiodothyronine (T3) and thyroxine (T4), from the thyroid gland. When TSH secretion is suppressed, the thyroid gland produces less T3 and T4, leading to decreased levels of these hormones in the blood and potentially causing hypothyroidism.

Another way in which AAS can impact thyroid hormones is by altering the conversion of T4 to T3. T4 is the main form of thyroid hormone produced by the thyroid gland, but it is not as biologically active as T3. The conversion of T4 to T3 is an important step in the regulation of metabolism, as T3 is the active form of thyroid hormone that stimulates metabolic processes. AAS can interfere with this conversion, leading to decreased levels of active T3 in the blood and a decreased metabolic rate.

It’s also worth noting that the effects of anabolic steroids on thyroid hormones can vary depending on the dose, duration, one’s genetic response to AAS and the type of AAS used. A clear example of this is Stanozolol (Winstrol), which has been shown to have a greater impact on thyroid hormones than others.

These negative effects can result in hypothyroidism and decreased metabolic rate, among other symptoms. In other words, AAS may slow down one’s metabolism and make it harder for the user to lose fat.

My proposed solution

Knowing that it is possible for AAS to worsen thyroid function, it would make sense for AAS users to incorporate T3 in their cutting cycles.

Many bodybuilders take high doses of T3 during their cutting cycles to lose more fat, but that comes with serious health risks. Using a low dose of T3 may be enough to offset the negative impact of AAS on endogenous thyroid production WITHOUT causing additional side-effects like increased heart rate and blood pressure.

If you are an advanced bodybuilder, you are probably already using high doses of T3 with your cutting cycles, so you don’t need to worry about taking any additional steps.

If you are not willing/ready to take high doses of T3 but you still want to optimize your thyroid function during cutting cycles with AAS, you should consider taking 12.5 to 25mcg of T3 per day.

Note that you will suppress your endogenous thyroid production by shutting down TSH, regardless of what T3 dose you use. No “PCT” is required for your thyroid hormones as it only takes a couple of weeks for them to bounce back, just try not to stuff yourself with food for a couple of weeks after T3 cessation.


In conclusion, AAS can have a negative effect on thyroid production, so using thyroid hormones during cutting cycles would be highly beneficial for those bodybuilders who are looking to get the most out of their PED use.


William Davis

William has been studying and experimenting with bodybuilding pharmacology for over 6 years. After being an independent researcher for all these years, he has decided to share his knowledge with the bodybuilding community through his science-based articles. His approach to enhanced bodybuilding can be summed up in the saying “less is more”, as he believes that prioritizing harm mitigation and looking for ways to maximize the positives is the key to longevity in bodybuilding.

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