Sir Brain & Mr. Testicles

What You Need to Know:

#1: Sir Brain drives testosterone production; Mr. Testicles follows orders

#2: Personalized testing will indicate which medication will be most effective to boost testosterone levels


Testosterone begins to decline at age 30, at 1% per year. You're probably familiar with symptoms of low testosterone: decreased muscle mass, weight gain, reduced sex drive, erectile dysfunction, depression and increased risk of cardiovascular death. Essentially turning into your grandfather 👴🏻

However, the majority of American men with low testosterone are untreated.

Testosterone Replacement Therapy

Testosterone comes in a variety of formulations: orals, gels, patches, pellets and injectables, among others.

But, think twice before reaching for that syringe of testosterone.

Which strategy do you think will produce better results: Injecting yourself with foreign testosterone or stimulating your body to produce its own testosterone?

Correct, the latter.

And that's not all! Other risks of testosterone replacement therapy include:

Say no to

Moobs &


  • Liver toxicity

  • Excessive red blood cell production

  • Breast development

  • Testicular shrinkage

  • Infertility

  • Sleep apnea

Sorry man, but those moobs and mini-huevos aren't cute. Boost your testosterone the smarter and safer way. To better understand, listen to a conversation between Sir Brain and Mr. Testicles.

Sir Brain & Mr. Testicles

Sir Brain and Mr. Testicles use hormone levels to communicate with one another. This conversation is a feedback loop, a self-adjusting system of checks and balances which maintains testosterone levels within the ideal range. Sir Brain is the man in charge and drives testosterone production through release of lutenizing hormone [LH]. Based on blood levels of sex hormones, Sir Brain will increase or decrease release of lutenizing hormone [LH].

Sir Brain: Rise and shine Mister Testicles! Testosterone levels are low. Don't just hang there; get to work!

Mr. Testicles: (Gathering sack together) Good mornin' Sir Brain. But how much testosterone do I need to produce?

Sir Brain: Dumb Mr. Testicles. We do the same routine every morning. Just listen to my orders. I send the lutenizing hormone [LH] and you produce the testosterone. The more lutenizing hormone [LH] I send, the more testosterone you secrete. Easy.

Mr. Testicles: You're so smart Sir Brain. I'll wait for the lutenizing hormone [LH].

(Mr. Testicles combs hair while waiting for communication from Mr. Testicles... The lutenizing hormone [LH] arrives at the testes)

Mr. Testicles: Oh that tickles! Releasing the testosterone now.

(Based on concentrations of sex hormones in the blood, Sir Brain will adjust release of lutenizing hormone [LH] to maintain testosterone levels within the ideal range.)

Testosterone Feedback Loop

Sir Brain begins the cycle by releasing lutenizing hormone [LH], which travels through the blood and stimulates Mr. Testicles to produce testosterone [T]. Testosterone acts on testosterone receptors throughout the body, or can be converted into dihydrotestosterone [DHT] or estrogen [E1 & E2]. Sir Brain monitors levels of sex hormones by sampling the concentration of estrogen in the blood. If levels are low, Sir Brain will release more lutenizing hormone [LH]; if levels are too high, Sir Brain will release less lutenizing hormone [LH]. This is called a feedback loop.

Blood Testing

First, test your blood to see if your testosterone level is low or low normal.

If your testosterone is low, further blood work will measure levels of your other sex hormones, including lutenizing hormone [LH] and the estrogens [E1 & E2].

Based on the complete picture of all sex hormones, a targeted medication will be selected to boost your testosterone level.


Step 1: Measure testosterone level

Determine if you have low testosterone, by measuring:

With age, men produce less testosterone and more sex hormone binding globulin [SHBG]. The result is a smaller and smaller amount of free testosterone, which is the biologically active form. Image adapted from

With age, men produce less testosterone and more sex hormone binding globulin [SHBG]. The result is a smaller and smaller amount of free testosterone, which is the biologically active form. Image adapted from

Testosterone [T] Typically measured as total testosterone in the blood. The normal range of total testosterone is 300-1000 ng/mL. The level should be measured between 7-11AM when levels are highest. Salivary and capillary (finger prick) testing may provide more accurate measurements of tissue testosterone levels.

Sex Hormone Binding Globulin [SHBG] The majority of testosterone in the blood is bound to a carrier protein called SHBG. When bound to this protein, testosterone is unable to stimulate the testosterone receptor. Measuring SHBG allows for calculation of bioavailable testosterone, the amount of testosterone that is free to stimulate the testosterone receptors.


Step 2: measure other sex hormones

If you have low testosterone, measure levels of your other sex hormones:

Lutenizing Hormone [LH] Released from the brain, this hormone travels to the testes, where it stimulates production of testosterone. Shares structural similarity with human chorionic gonadotropin [hCG].

Dihydrotestosterone [DHT] Synthesized from testosterone via the enzyme 5-alpha reductase. Unlike testosterone, DHT cannot be converted into estrogen. DHT is responsible for development of secondary sexual characteristics, including: voice deepening, facial hair and pubic hair. Balding men may take the medication finasteride [Propecia], which blocks conversion of testosterone into DHT.

Estrone [E1] Natural form of estrogen produced in fat tissue.

Estradiol [E2] An estrogen produced from testosterone via the enzyme aromatase. Based on the concentration of estradiol in the blood, Sir Brain will increase or decrease release of lutenizing hormone [LH]. Estradiol [E2] is more potent than estrone [E1].    


STEP 3: medications

Based on the levels of your sex hormones, consider these medications:

hCG [Human Chorionic Gonadotropin]: Shares structural similarity with lutenizing hormone [LH] and therefore stimulates testes to produce testosterone. Naturally secreted by the placenta and isolated from the urine of pregnant women for medical use. Given as an intramuscular injection 2-3 times weekly. If a man's level of lutenizing hormone [LH] is already high, hCG will not be an effective medication. That's why it's important to measure your blood! Instead, consider one of these other medications:

Clomid [Clomiphene]: Sir Brain continually samples the level of sex hormones in the blood. If estradiol [E2] levels are low, the brain will increase release of lutenizing hormone [LH] to bolster testosterone production; however, if sex hormone levels get too high, the brain will decrease release of lutenizing hormone [LH] to bring testosterone levels back down to the normal range. Clomid blocks the brain's ability to detect sex hormone levels, thereby tricking Sir Brain into thinking that levels are lower than they really are, thereby preventing negative feedback. The result is an increase in lutenizing hormone [LH] which will travel to Mr. Testicles and induce production of more testosterone. Clomid is a well-tolerated oral medication with few side effects and doesn't cause a decrease in testicular size.

Arimidex [Anastrozole]: This oral medication blocks the enzyme aromatase, which converts testosterone to estrogen. Aromatase is found in fat tissue. One reason why an overweight man may have a low testosterone level is due to excessive conversion of testosterone to estrogen in fat tissue. Arimidex can block this inappropriate conversion and restore testosterone levels.

What about a natural supplement to boost testosterone?

Eurycoma longifolia [Tongkat Ali]: A medicinal plant native to Southeast Asia. Traditionally, men consume the liquid of boiled plant roots to boost energy and sex drive (Effendy). The root contains dozens of chemically active compounds, which increase testosterone by a variety of mechanisms such as: stimulating testes to produce testosterone, blocking conversion of testosterone into estrogen and decreasing sex hormone binding globulin [SHBG] thereby increasing the amount of free testosterone (George & Henkel). Can be purchased in capsule or powder form.

Note: I do NOT recommend manipulating testosterone levels--including consuming Eurycoma longifolia--without periodic blood testing under the supervision of a licensed physician.



"Sir Brain & Mr. Testicles" by Melody Huang, an NYC-based illustrator and designer. Contact her for more information:


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Effendy, Nadia Mohd, et. al. "Eurycoma longifolia: Medicinal Plant in the Prevention and Treatment of Male Osteoporosis due to Androgen Deficiency" Evid Based Complement Alternat Med. 2012; 2012: 125761.

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