Thread: Clomid vs. Nolvadex
11-30-2004, 03:06 PM #1
Clomid vs. Nolvadex
I have been researching these two compounds for my upcoming cycle and from what I am reading, it appears that Nolvadex is the weapon of choice during the cycle, but that it is also the weapon of choice for PCT as well. The information I found indicated that both Clomid and Nolvadex are anti-estrogens and both block estrogen by blocking up estrogen receptors in tissue, leaving estrogen in the body inert. I read further that Clomid also suppresses natural test production, while Nolvadex encourages it by increasing effectiveness of LH (leutinizing hormone - it stimulates the pituatary gland to release test). I have also read that Nolva acts more as an estrogen in the liver which lowers colestoral levels. I have inlcuded the link below to where I got some of my info...the rest I got just looking up "Nolvadex" on Google. This is an area of concern for me...both in blocking unwanted side effects and PCT...does anyone have any comment or advice in this regard?
11-30-2004, 03:13 PM #2
11-30-2004, 03:23 PM #3
I have read them...I will go with the Clomid for PCT as recommended...but check the link I posted...it almost tells the opposite...and the links below also state that Clomid does not actively restart natural test...this is why I am confused about this...however, I will use Clomid PCT...
11-30-2004, 03:37 PM #4
You should read Pheednos pct thread. It's the pct bible.:
Now IMO, selective estrogen receptor modulators(SERMs) such as Clomiphine and Tamoxifen are selective to which tissues they bind too. Clomid being selective to the suprapituitary, while Tamox is selective to breast, bone, and liver ERs. I've come to this conclusion based on the comparison of studies on both SERMs. In every study showing benefit to HPTA from tamoxifin, the duration of the administration is 3-12months(This includes studies cited by William Llewellyn in his Nolva vs Clomid article). In studies showing levels of LH, FSH, and Testosterone checked after short durations of tamox, they were either insignificant, or their was an actual drop. I believe this is because tamox selectively works at the mammery(as well as bone and liver), thus taking longer for LH stimulation to occur.
With clomid, benefit to gonadotrophin concentrations, LH, FSH, and serum testosterone can be seen in short periods of 2-6wks. Because of the apparent selective nature of the two, and given our usual PCT duration, clomid is by far superior at LH stimulation than Nolva.
11-30-2004, 03:41 PM #5
That is what I wanted to see...some clear science that makes sense...thanks for all your help...sorry to cause so much trouble. I am definately using Clomid for PCT...
How many clomid tabs will I need for PCT? I do not even know what strength they come in...
11-30-2004, 03:48 PM #6Originally Posted by BigJames
Day 1: 300mg
Some people choose to run 100mg/day from Day 2-21, depending on the strength and duration of their cycle, which will bump the mg total needed to 2300mg. Base your purchase off of these numbers and you'll be safe
11-30-2004, 05:13 PM #7
Clomid and Nolvadex
I am not sure how Clomid and Nolvadex became so separated in the minds of bodybuilders. They certainly should not be. Clomid and Nolvadex are both anti-estrogens belonging to the same group of triphenylethylene compounds. They are structurally related and specifically classified as selective estrogen receptor modulators (SERMs) with mixed agonistic and antagonistic properties. This means that in certain tissues they can block the effects of estrogen, by altering the binding capacity of the receptor, while in others they can act as actual estrogens, activating the receptor. In men, both of these drugs act as anti-estrogens in their capacity to oppose the negative feedback of estrogens on the hypothalamus and stimulate the heightened release of GnRH (Gonadotropin Releasing Hormone). LH output by the pituitary will be increased as a result, which in turn can increase the level of testosterone by the testes. Both drugs do this, but for some reason bodybuilders persist in thinking that Clomid is the only drug good at stimulating testosterone. What you will find with a little investigation however is that not only is Nolvadex useful for the same purpose, it should actually be the preferred agent of the two.
Studies conducted in the late 1970's at the University of Ghent in Belgium make clear the advantages of using Nolvadex instead of Clomid for increasing testosterone levels (1). Here, researchers looked the effects of Nolvadex and Clomid on the endocrine profiles of normal men, as well as those suffering from low sperm counts (oligospermia). For our purposes, the results of these drugs on hormonally normal men are obviously the most relevant. What was found, just in the early parts of the study, was quite enlightening. Nolvadex, used for 10 days at a dosage of 20mg daily, increased serum testosterone levels to 142% of baseline, which was on par with the effect of 150mg of Clomid daily for the same duration (the testosterone increase was slightly, but not significantly, better for Clomid). We must remember though that this is the effect of three 50mg tablets of Clomid. With the price of both a 50mg Clomid and 20mg Nolvadex typically very similar, we are already seeing a cost vs. results discrepancy forming that strongly favors the Nolvadex side.
Pituitary Sensitivity to GnRH
But something more interesting is happening. Researchers were also conducting GnRH stimulation tests before and after various points of treatment with Nolvadex and Clomid, and the two drugs had markedly different results. These tests involved infusing patients with 100mcg of GnRH and measuring the output of pituitary LH in response. The focus of this test is to see how sensitive the pituitary is to Gonadotropin Releasing Hormone. The more sensitive the pituitary, the more LH will be released. The tests showed that after ten days of treatment with Nolvadex, pituitary sensitivity to GnRH increased slightly compared to pre-treated values. This is contrast to 10 days of treatment with 150mg Clomid, which was shown to consistently DECREASE pituitary sensitivity to GnRH (more LH was released before treatment). As the study with Nolvadex progresses to 6 weeks, pituitary sensitivity to GnRH was significantly higher than pre-treated or 10-day levels. At this point the same 20mg dosage was also raising testosterone and LH levels to an average of 183% and 172% of base values, respectively, which again is measurably higher than what was noted 10 days into therapy. Within 10 days of treatment Clomid is already exerting an effect that is causing the pituitary to become slightly desensitized to GnRH, while prolonged use of Nolvadex serves only to increase pituitary sensitivity to this hormone. That is not to say Clomid won't increase testosterone if taken for the same 6 week time period. Quite the opposite is true. But we are, however, noticing an advantage in Nolvadex.
The Estrogen Clomid
The above discrepancies are likely explained by differences in the estrogenic nature of the two compounds. The researchers' clearly support this theory when commenting in their paper, "The difference in response might be attributable to the weak intrinsic estrogenic effect of Clomid, which in this study manifested itself by an increase in transcortin and testosterone/estradiol-binding globulin [SHBG] levels; this increase was not observed after tamoxifen treatment". In reviewing other theories later in the paper, such as interference by increased androgen or estrogen levels, they persist in noting that increases in these hormones were similar with both drug treatments, and state that," …a role of the intrinsic estrogenic activity of Clomid which is practically absent in Tamoxifen seems the most probable explanation".
Although these two are related anti-estrogens, they appear to act very differently at different sites of action. Nolvadex seems to be strongly anti-estrogenic at both the hypothalamus and pituitary, which is in contrast to Clomid, which although a strong anti-estrogen at the hypothalamus, seems to exhibit weak estrogenic activity at the pituitary. To find further support for this we can look at an in-vitro animal study published in the American Journal of Physiology in February 1981 (2). This paper looks at the effects of Clomid and Nolvadex on the GnRH stimulated release of LH from cultured rat pituitary cells. In this paper, it was noted that incubating cells with Clomid had a direct estrogenic effect on cultured pituitary cell sensitivity, exerting a weaker but still significant effect compared to estradiol. Nolvadex on the other hand did not have any significant effect on LH response. Furthermore it mildly blocked the effects of estrogen when both were incubated in the same culture.
To summarize the above research succinctly, Nolvadex is the more purely anti-estrogenic of the two drugs, at least where the HPTA (Hypothalamic-Pituitary-Testicular Axis) is concerned. This fact enables Nolvadex to offer the male bodybuilder certain advantages over Clomid. This is especially true at times when we are looking to restore a balanced HPTA, and would not want to desensitize the pituitary to GnRH. This could perhaps slow recovery to some extent, as the pituitary would require higher amounts of hypothalamic GnRH in the presence of Clomid in order to get the same level of LH stimulation.
Nolvadex also seems preferred from long-term use, for those who find anti-estrogens effective enough at raising testosterone levels to warrant using as anabolics. Here Nolvadex would seem to provide a better and more stable increase in testosterone levels, and likely will offer a similar or greater effect than Clomid for considerably less money. The potential rise in SHBG levels with Clomid, supported by other research (3), is also cause for concern, as this might work to allow for comparably less free active testosterone compared to Nolvadex as well. Ultimately both drugs are effective anti-estrogens for the prevention of gyno and elevation of endogenous testosterone, however the above research provides enough evidence for me to choose Nolvadex every time.
bottom line is you need either one of them for postcycle therapy ideally both.like he said Nolvadex would seem to provide a better and more stable increase in testosterone levels, and likely will offer a similar or greater effect than Clomid for considerably less money.
oc Natl Acad Sci USA 76:4460-3,1079
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