Free shipping on orders over $100!
(USA Orders Only) Shop Now >

Addressing low free testosterone levels

My total testosterone levels are pretty high at 775ng/dl but my free testosterone is very low at only 8 pg/ml. What can I do to increase free testosterone levels?

First, if you engage in intense training and fail to take a few days off to rest before getting your blood drawn, you may have low blood levels of free testosterone due to androgen receptor uptake. I would not be as concerned with low free testosterone levels if you fall into this category and also have a high motivation, and drive,  and don’t have any issues with building muscle and strength. However, if your sex drive is low, you’re moody, and don’t have a strong feeling of genuine confidence then keep reading for advice on increasing free testosterone levels.     

One possible explanation for your low free testosterone levels may be too much consumption of fiber. The daily recommendation of around thirty grams of fiber daily is not likely an issue but if you are on a plant-based diet, for example, your fiber intake may be several times higher which can be problematic for optimal free testosterone levels. According to supplement expert and frequent ASC Show guest Jerry Brainum, a high-fiber diet raises levels of sex hormone-binding globulin (SHBG) and excessive levels of SHBG prevent free testosterone from being utilized by androgen receptors. While SHBG functions to transport testosterone in the bloodstream to be utilized at various receptor sites too much SHBG inhibits the utilization of free testosterone. 

To calculate the ideal levels of SHBG take a page from Dr. Mark Gordon and add the bottom of the range to the top of the range and divide by two. For example, the normal range of SHBG is 10 to 57 nmol/L, so divide 67 by two and the optimal range is around 33.5 or below. If SHBG is too low it will inhibit the transport of testosterone so just like ideal estrogen markers, you don’t want to be too low or too high. 

Your total testosterone levels are excellent so I doubt your dietary fat intake is insufficient but just in case make sure to avoid reducing dietary fat intake below 20% of total calories. Personally I prefer my dietary fat intake to be around 30% of overall caloric intake. When my dietary fat intake is too low I experience a negative impact on training performance, sex drive, and mood. If you consume too much fat (over 40% of total caloric intake) you may develop insulin resistance and experience a rise in fasting glucose levels despite limited carbohydrate intake. Too much fat weakens insulin receptors which can cause an increase in blood glucose levels. More than the consumption of carbohydrates being the cause of excess glucose levels is too much intake of refined carbohydrates on top of too much intake of dietary fats, especially poor quality fats such as transfats. 

Make sure to choose fat sources that have the most positive impact on optimal testosterone production such as olive oil. According to Brainum, fat, especially saturated fat found in coconut oil and cacao is involved with cholesterol synthesis in the liver and cholesterol is the building block for all sex hormones including testosterone. Olive oil and coconut oil have been shown to help convert cholesterol into testosterone in the testes as well. 

Brainum also conveys that polyunsaturated fats such as what is in vegetable oils, flaxseeds, and hempseed have no impact on testosterone (don’t lower or raise) while trans fats definitely lower testosterone levels so avoid those completely as other health complications are also indicated with transfat intake. Also, just because polyunsaturated fats such as flaxseeds and hempseed don’t directly support testosterone production, it doesn’t mean they should be avoided as both have numerous benefits. Hempseeds are high in protein, and testosterone production supporting minerals zinc and magnesium. Flaxseeds help mitigate excess inflammation and also improve the ratio of good to bad estrogens (2 hydroxy estrone to 4 and 16 hydroxy estrone). 

Next, make sure your intake of the minerals magnesium, selenium, boron, and zinc is adequate. Depleted levels of these minerals can lower free testosterone levels. Hempseeds and pumpkin seeds are excellent sources of magnesium and zinc and apples, potatoes, and legumes are high-quality sources for boron. Just a few Brazil nuts provide over 100mcg of selenium. I add a few to my morning shake. In addition, all of the herbs in my natural testosterone booster ASTB support both total and free testosterone levels. 

I have been using ASTB and it’s amazing! My T levels went from 321 ng/dl to 619 ng/dl and free from 11 to 19,7. I feel great and free! 

–Jimmy Solano 

Recently tested testosterone levels were outstanding: 912 ng/dl total and 29.2 pg/ml free (which the lab flagged as high!  I am 57.  Kudos.

–Mark F 

DHEA supplementation at 50mg has been shown to increase free testosterone in middle-aged trainees after high-intensity interval training. Testosterone levels can go down after an intense interval training session especially when you get older and DHEA may help mitigate this. This is likely due to reducing excess cortisol levels. Stress is the killer of testosterone. My guess is systemic enzymes also support testosterone levels when taken post-workout by mitigating excess inflammation and subsequently excess cortisol.

Finally, keep in mind your free testosterone levels should account for around 2% of your total testosterone levels. If you have a total testosterone level of  800 ng/dl your free testosterone levels should be at least 16 pg/ml. Again, if you engage in intense training make sure to take a few days off before having free testosterone levels measured for a more accurate reading. 

For more information on testosterone and all things nutrition, training, and supplements, make sure to subscribe to Jerry Brainum’s exceptional newsletter at


Everything You Need to Know About Testosterone and How to Optimize Levels

Subscribe to Aggressive Strength Magazine and Get My Latest Report, Everything You Need to Know About Testosterone and How to Optimize Levels