Is 3,5-Diiodo-L-Thyronine (T2) the Secret Ingredient to Weight Loss Success?

Is 3,5-Diiodo-L-Thyronine (T2) the Secret Ingredient to Weight Loss Success?

Slimming pills, crash diets and an excessive amount of cardio are among just a few of the tactics you will see adopted by those looking to lose weight. Not only are there serious health risks associated with being overweight, but there are lots of us who to lose weight for aesthetic reasons.

There are a huge number of slimming pills and fat burners available on the market, all with varying degrees of credibility through science and anecdotal feedback. Stimulant-based products are generally well received with users pointing towards increased thermogenesis and appetite suppression as two key factors to aid their weight loss. Despite the benefits and genuine merits of some of these products, they can have their downside and certain users do report occasional side effects such as jitters and nausea. There are a number of ways to achieve weight loss through diet and exercise but there are also certain supplements that can be great for aiding this process. Whilst stimulant-based fat burners are undoubtedly more popular, products from the non-stimulant category can often be unfairly overlooked as users do not “feel” as much from them.

One non-stimulant ingredient that has received an abundance of positive anecdotal feedback is the ingredient 3,5-diiodo-L-thyronine (T2), found in iForce Dexaprine and TT-33 which works similarly to how thyroid hormone does . A recent study was conducted to find out what effects 3,5-diiodo-L-thyronine (T2) had on the RMR (Resting Metabolic Rate: the rate at which your body burns calories while you rest) and weight gain in rats on a high fat  content diet.

The study indicated that this compound did prevent weight gain in the rats on a high fat diet and stimulated the RMR of the rats.

A second study was conducted to explore these findings further in 2011. Antonelli et al at the University of Pisa, Italy, engineered an experiment that investigated long term administration of T2 on humans.

Two subjects, with normal thyroid function, volunteered to receive the T2 compound. Their body weight, body mass index, blood pressure, heart rate, electrocardiogram, thyroid and liver ultrasonography, glycemia, total cholesterol, triglycerides, free T3 (FT3), free T4 (FT4), T2, thyroid stimulating hormone (TSH) and RMR were assessed and recorded at baseline and at the end of treatment.


It was found that, in both participants, RMR increased considerably after treatment and after continuing the T2 usage for a further 3 weeks (at 300 mcg/day), body weight was reduced significantly (p<0.05) (about 4%), while the serum levels of FT3, FT4 and TSH, were unchanged.

It is also important to note that there were no cardiac side effects observed in either participant and that no significant change was observed in the same participants when receiving the placebo.

Our Comments  

This study supports the hypothesis that 3,5-diiodo-L-thyronine (T2) increases the RMR and reduces body weight  in humans without undesirable side effects.

Factors were controlled closely during this study, focusing on a small group of participants, controlling diet, and ensuring that post and pre study biological values were recorded, such as body weight, body mass index, blood pressure etc.

There are opportunities for future assessments on 3,5-diiodo-L-thyronine (T2) through expanding the number of participants in the sample and to expand the variants in these participants, for example age range and gender.

Using T2 seems an effective way to boost RMR function and aid weight loss; this is clear from the human study. However, whether these results would be similar on a larger sample is unclear. Without further testing, drawing concrete conclusions from these results is difficult.


Antonelli, A et al.. (2011). 3,5-diiodo-L-thyronine increases resting metabolic rate and reduces body weight without undesirable side effects. . PubMed. 25 (4), 655-660.