Clomid

Clomid is a drug of the class known as Selective Estrogen Receptor Modulators (typically called a “SERM” in steroid jargon). Its original use was as a fertility aid given to women, and later to men also. If we really want to understand what Clomid does, we need to take a look at the actual type of drug it is: Selective Estrogen Receptor Modulator. This means that it selectively acts in tissues as either an estrogen agonist or antagonist, depending on the tissue. In breast tissue, and other areas like the pituitary, it acts by binding to the estrogen receptor and hence blocking estrogen from doing the same. This is where it is known as an estrogen antagonist. In other tissues, like the liver, it may act as an estrogen agonist, and actually mimic some of the positive effects of estrogen on these tissues.

Clomid is a drug of the class known as Selective Estrogen Receptor Modulators (typically called a “SERM” in steroid jargon). Its original use was as a fertility aid given to women, and later to men also. If we really want to understand what Clomid does, we need to take a look at the actual type of drug it is: Selective Estrogen Receptor Modulator. This means that it selectively acts in tissues as either an estrogen agonist or antagonist, depending on the tissue. In breast tissue, and other areas like the pituitary, it acts by binding to the estrogen receptor and hence blocking estrogen from doing the same. This is where it is known as an estrogen antagonist. In other tissues, like the liver, it may act as an estrogen agonist, and actually mimic some of the positive effects of estrogen on these tissues.

This is actually advantageous when it binds to estrogen receptors located in the breast tissue, as it prevents estrogen from binding there, which can ultimately cause gynocomastia (development of breast tissue in males). It’s not a particularly strong antagonist in breast tissue, however, and most people wouldn’t use it to prevent gyno except for under the most extreme circumstances (i.e. a very low dose cycle, or if there was nothing else on hand). I have used it on what could be considered lower dose cycles, and found it to be decent for maintaining testicle size as well as for preventing gyno to a small degree. When I was using moderate to high doses, even high doses of Clomid weren’t enough to do this. Clomid also opposes the negative feedback loop that the body relies on in terms of estrogen related inhibition of the HPTA  (Hypothalamic-Pituitary-Testicular-Axis). (1) It likely does this by acting as an estrogen antagonist in certain tissues. This effect in turn stimulates both LH (Leutenizing Hormone)and FSH (Follicle Stimulating Hormone), which then stimulates the release of testosterone. For this reason, we typically see Clomid used in PCT routines. Personally, I’m a fan of another SERM in this regard. For reference purposes, 150mgs of Clomid will elevate testosterone levels to approximately 150% of initial baseline value (1). You don’t have to use 150mgs, however; In my research, I’ve found that doses as low as 50mgs will show improvements and elevations in testosterone levels (2).

Clomid is actually a very safe drug, even when used for long periods of time in the clinical treatment of lowered testosterone levels (2). I’ve seen it used for up to four months in studies, with no adverse effects- and certainly this is much longer than most people would be running a PCT for. 

On a personal note, I found that I saw “floaters” when I ran very high doses of Clomid for too long. Research shows that optic neuropathy (the technical name for what I was experiencing) is not uncommon with Clomid usage. (3)(4)