There are many interrelated causes of low testosterone and male sexual dysfunction.
These include:
Excess Cortisol
- Corticosteroid drugs such as prednisone.
- Stress increases cortisol production and can deplete DHEA (which is called pregnenolone steal)
[which can directly decrease testosterone precursors].
- Increased cortisol can suppress TSH, decrease conversion of T4 to T3, and increase conversion of T4 to
inactive reverse-T3 [low free-T3 causes hypothyroid symptoms, see below].
- Increased cortisol can increase production of Sex Hormone Binding Globulin (SHBG)
[which reduces free testosterone].
- Increased cortisol can increase blood glucose, which is converted to visceral fat [see below].
- Increased cortisol can reduce pituitary production of LH [see below].
Optimizing free-T3 can double free testosterone.
- Stress [see above].
- Hashimoto's Thyroiditis.
- Nutritional Deficiencies [Iodine, tyrosine, iron, zinc, etc - test don't guess!].
- Surgical destruction of thyroid gland.
Excess alcohol intake
- Can suppress hypothalamus/pituitary axis [see below].
- Promotes visceral fat deposits ("beer-belly") [see below].
Excess Visceral Fat Deposits (Obesity)
- Visceral fat contains the enzyme aromatase that converts testosterone to estrogen.
- This reduces free testosterone and adds unhealthy levels of estrogen.
Hypothalamic Dysfunction
- Low production of gonadotropin-releasing hormone, GnRH.
- GnRH is needed to stimulate the pituitary to make luteinizing hormone, LH [see below].
- Excess estrogen, progesterone, or testosterone can suppress GnRH via a negative feedback loop.
Pituitary Dysfunction
- Low production of luteinizing hormone, LH.
- LH is needed to stimulate testosterone production in the testes.
Overtraining
Excessive exercise associated with body-building or performance training can suppress sexual function,
partly as a result of increased stress [see above]. This phenomena is well known in women, where
loss of menstrual function is one component of the "female athletic triad".
Atherosclerosis of the arteries serving the genital area limits blood from flowing into the penis to
enlarge it.
Autonomic Nervous System Compromise
Proper coordination of both the sympathetic and parasympathetic nervous systems is necessary to produce
erection and ejaculation.
- Problems in the spine can prevent proper functioning or one or both of these parts of the nervous system.
- Metabolic problems such as diabetes can damage small nerves controlling erection and ejaculation.
Sleep Disorders
- Reduces GnRH [suppresses hypothalamic-pituitary function]
- Sleep apnea
- One week of sleep loss can reduce testosterone production by 15% [Leproult2011].
Inflammation
- Increased levels of inflammatory mediators such as IL-6 reduces testosterone levels [Maggio2008].
Drugs
- Statins [reduce production of cholesterol and all other steroid hormones including testosterone] [Neel2019].
- Fibrates [reduce absorption of cholesterol] [Neel2019].
- Corticosteroids such as prednisone [see Excess Cortisol above] [Neel2019].
- Opiates.
- Anti-anxiety medications such as benzodiazepines (e.g. Valium) [Neel2019].
- Anti-depression medications such as SSRIs (e.g. Prozac), dopamine antagonists, tricyclics,
monoamine oxidase inhibitors (MAOIs), and lithium [Neel2019].
- Blood pressure medications such as spironolactone, beta blockers [Neel2019].
- Antipsychotics [Neel2019].
- Cetrotide (cetrorelix) a gonadotropin-releasing hormone (GnRH)
antagonist used to block FSH and LH production.
- H-2 blockers, especially cimetidine/Tagamet [Neel2019].
- Anticonvulsants [Neel2019].
- Estrogens and progestins, including birth control pills [suppress GnRH production].
- Sulfonylureas [suppresses testosterone and thyroid]
- Anti-androgens to treat hair-loss, prostate cancer, or hirsutism
(e.g. finasteride/Proscar, dutasteride/Avodart, flutamide/Eulexin, nilutamide/Nilandron/Anandron).
- Ketoconazole and some other antifungal drugs.
- Nonsteroidal anti-inflammatory drugs ???
Envionmental Endocrine Disruptors
- Plastic products:
Avoid when possible, and especially do not cook in plastic containers.
- BPA [additive in polycarbonate (#7) plastics found in cans, bottles, and food utensils] [EWG2013].
- Phthalates [additive in plastic food containers and wrap, children's toys] [EWG2013].
- Water contaminants:
Use water filter or glass bottled water from safe sources.
- Food contaminants:
- Soy, and other phytoestrogens.
- Mercury [many fish] [EWG2013].
- Other:
- Fire retardants [may be in dust] [EWG2013].
- Dioxin [hard to avoid] [EWG2013].
- perfluorinated chemicals (e.g. PTFE = Teflon) [persistent in the environment] [EWG2013].
- Organophosphate pesticides [EWG2013].
- Glycol esters [solvents and cosmetics] Glycol esters [EWG2013].
Electromagnetic radiation
[Gye2012] have collected a summary of many studies of the effect of electromagnetic field (EMF)
on reproductive function in vivo and in vitro. While effects were demonstrated, the data presented was
insufficient to evaluate the effects of real-world exposures; further research (and study of the referenced
primary literature) is necessary to establish sufficient context.
However, Dr. Weyrich feels it is safe to say that sitting with a laptop on ones lap for prolonged periods
of time may not be a good idea; however, since the strength of EMF fields decays with the cube of the distance,
placing the laptop on one's desk would significantly reduce the exposure.
Light pollution
Light pollution disrupts circadian, lunar, solar, and other natural rhythms.
Modern society has been said to live in "endless summer" due to the increasing use of electric lights
and communication devices. This disrupts hormonal cycles.
In particular, the use of cell phones in bed disrupts hormonal rhythms and also tends
to be a "big turn-off."
Inadequate "Earthing
The Earth itself generates low frequency electromagnetic fields that have been
shown to affect fertility and other aspects of wellbeing.
This benefit is prevented when an individual's body is insulated from the ground.
Walking barefoot (in safe areas) and sleeping on a specially grounded mat may therefore
benefit sexual well-being of both men and women.
Other
- Elevated insulin may contribute to erectile dysfunction, or it may simply be an effect
of diabetes mellitus type II or syndrome X.
- According to [VIVO2019], "leptin appears to be a significant regulator of reproductive function.
These effects are probably due in part to the ability of leptin to enhance secretion of
gonadotropin-releasing hormone from the hypothalamus, and thus luteinizing and follicle-stimulating
hormones from the anterior pituitary."
- [Elsaied2019] have shown that "decreased adiponectin and testosterone are associated with
[erectile dysfunction] in [type 2 diabetes mellitus]," but did not correlate with with the scores of
international index of erectile function (IIEF), possibly due to a small number of patients studied.
- Various vitamin, mineral, protein, and fat imbalances or deficiencies can disrupt many components of the
endocrine system. Note that in some cases, even though there is adequate nutritional intake, absorption
may be prevented by factors including certain diseases (e.g. celiac sprue) or drug intake (e.g. antacids
or certain cholesterol lowering drugs).
- Smoking or other Nicotine Intake. Nicotine is a vasoconstrictor that can reduce blood flow in many
parts of the body, including the genitals.
- Marijuana and other recreational drugs.
- Depression, interpersonal relationship,and other psychological factors.
