Free testosterone

Only 3 Supplements You Need to Optimize Free Testosterone

In Food and Supplements, Free Testosterone and SHBG by Marcel3 Comments

Free testosterone is testosterone that is unbound to anything, making it bioavailable. Only 1-2% of your total testosterone is free. The way you increase your free testosterone is by lowering your sex hormone-binding globulin (SHBG). SHBG is a glycoprotein that binds to the two sex hormones: androgen and estrogen. Other steroid hormones such as progesterone, cortisol, and other corticosteroids are bound by transcortin. Testosterone and estradiol circulate in the bloodstream, bound mostly to SHBG and to a lesser extent serum albumin and corticosteroid-binding globulin (CBG) (AKA transcortin).

Biggest Impacts on Free Testosterone

The biggest impactors on free testosterone are lowering your estrogen and eating more carbs.

This study found that men eating high carb/low protein had consistently higher testosterone levels and consistently lower cortisol levels than men eating high protein/low carb.

This study looked at 2 groups. One ate 30% carbs, the other 60% carbs. The group which got the lower amount of carbs, had significantly lower free testosterone levels, and higher cortisol levels.

Only 3 Supplements to Optimize Free Testosterone

  1. Boron
  2. Magnesium
  3. Vitamin D


Boron is a less known mineral that is found to increase free testosterone and DHT by lowering SHBG. The media hasn’t caught up with this great mineral yet so its real cheap for now. Stack up on some boron before it becomes mainstream and prices go up.

This study shows supplementing with boron (10mg daily) decreased sex hormone binding globulin (SHBG), increased free testosterone, decreased estrogen (female hormone), and elevated DHT. What else can you ask for? Boron decreased SHBG and estrogen, it increased free testosterone and elevated DHT.

There’s not many studies on boron since its unknown. The studies it does have shows that it decreases estrogen in men and increases it in women.

This mineral is so cheap that I don’t mind the lack of research. Even if it doesn’t increase testosterone, its great for your bone strength. Pick yourself up a liquid form of boron (better absorption) or get yourself some dried prunes, they’re the fruit highest in boron content. 10 dried prunes equals about 3mg of boron.


Magnesium is a well known mineral mostly found in dark leafy greens, nuts and seeds, fish, and buckwheat. Its a great mineral that increases free testosterone.

This study concluded that supplementation with magnesium increases free and total testosterone levels in sedentary men and in athletes. The increases are higher in those who exercise than in sedentary individuals.

This study found that magnesium inhibits SHBG, therefore making more testosterone bioavailable.

This next study found out that in older men, higher serum magnesium levels correlate with higher testosterone levels and other anabolic hormones.

Get yourself some magnesium oil, rub it on your legs an hour before sleep, and sleep like a lion.

Vitamin D

You can get vitamin D from the sun, food, or from a supplementation. The last one is the easiest since most people aren’t out in the sun at least 2 hours a day, without a shirt. If you are the exception then skip this, your vitamin D levels are good.

This study is in men taking 3,332 IU of vitamin D for one year, after bringing up serum levels past an average of 50nmol/L increased testosterone from 10.7±3.9 nmol/l to 13.4±4.7 nmol/l. Bioactive and free testosterone also increased. The study suggests that vitamin D supplementation might increase testosterone levels.

This study found that a month of vitamin D supplementation at 1332 IU was able to increase insulin secretion by 34.3% in type 2 diabetic patients. This increased secretion was significantly correlated with serum vitamin D levels.

Then this study found that in subjects with Vitamin D deficiency and impaired fasting glucose, 10,000 IU daily for 4 weeks was associated with an increase in insulin sensitivity.

This next study found that men with sufficient D levels (> or =30 microg/l) had significantly higher levels of testosterone and FAI and significantly lower levels of SHBG when compared to D insufficient (20-29.9 microg/l) and D-deficient (<20 microg/l) men.

This study concluded vitamin D deficiency in Australian men may contribute significantly to the development of hip fracture through the effects of secondary hyperparathyroidism, resulting in increased bone loss.

This study found that vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa.

And this study found that vitamin D is necessary for reproductive functions of the male rat.

Vitamin D is one of the greatest vitamins for testosterone and other androgens. I use this vitamin D supplement and it lasts me years. Its a highly concentrated tincture, just one drop gives you 2,000 IUs of vitamin D.

And that’s about it. There’s not much out there on optimizing free testosterone. The biggest things would probably be lowering your estrogen and eating more carbs.


  1. Charles Sledge

    Nice site. Really in depth. Never heard a using boron for testosterone before will have to start using it. You should write a book. I’ve seen this type of stuff covered a lot but never in such detail like it is here.

  2. John Arnieri

    I’m looking for a great foundation Multivitamin what would you recommend ?

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