Nolvadex a Cancerogen?

The American Cancer Society lists tamoxifen as a known carcinogen, stating that it increases the risk of some types of uterine cancer while lowering the risk of breast cancer recurrence.[37] The ACS states that its use should not be avoided in cases where the risk of breast cancer recurrence without the drug is higher than the risk of developing uterine cancer with the drug.


not sure what female users do for pct but this might be a little valuable knowledge. Also, I’m not sure where, but I’ve read it also decreases IGF and GH in men. Any validity this?

According to the National Cancer Institute, Tamoxifen side effects for men include the risk of stroke, blood clots and cataracts. Men experience symptoms such as headache, skin rash, nausea and impotence.Tamoxifen may also cause infertility in patients taking the drug. Because there is the potential for harm to a fetus, it is recommended that patients do not attempt to conceive while on the drug. According to, patients taking Tamoxifen should avoid sun exposure, drink alcohol sparingly, eat well and get enough rest to avoid fatigue.

Read more: Tamoxifen Side Effects in Men |"

I freaked out when I first read about that particular statistic regarding tamoxifen use. I did however, delve into the matter in depth. Although tamoxifen does result in a statistically significant increase in the number of cancers recorded, (including the liver) this comes with the following provisos.

  1. Increases in cancer rates were generally recorded in long term chemotherapy situations, so the users in the study were female, and had been on the drug for 2-5 years of daily use. This is far above the usage levels of most bodybuilders, since most people don’t take nolva constantly for years on end and most men weigh more than women, making their effective mg/kg dosage to be even less.

  2. The actual numerical increase in cancers was still extremely small. In the case of liver cancer (the one that men would likely be at risk of), I think the risk jumped from 1 or 2 in 10000 to 4-5 in 10000. A marked increase, but still a very very small percentage.

This would lead to the conclusion that moderate use of tamoxifen for PCT and gyno prevention is relatively safe.

for PCT yes, but along extended cycles not just as PCT but a serm to combat elevated estrogen raises the chances a bit doesn’t it? I do 1-3 cycles a year :X

slim chances but enough to spook you just a lil

How bout this. Dont use nolvadex on cycle when there are better drugs available.

[quote]BONEZ217 wrote:
How bout this. Dont use nolvadex on cycle when there are better drugs available. [/quote]

I think I’ve told you like 3 times so far Nolva is all I got, and being a knucklehead I really really wanna run my cycle.

That’s why I asked, and will ask once more, are AI soulutions from research companies worth a shit or is it just flavored toilet water

Anyway, I think some people might find this Nolva info. usefull just as I have discovered today and won’t be running it while on, given I’m on 4-6 months out of the year.

btw u answered my Q in the other thread. my bad

looks like ill be doing test taper from now on haaaaaa

Yes, it – and I expect Clomid – have a very low and non-zero risk in this regard with chronic use. For this reason they shouldn’t be used continuously for years on end unless there is very good reason to do so.

Fortunately we no longer need rely on them for gyno protection.

Personally I consider the PCT use to be an entirely reasonable and extremely low risk.

In terms of hepatotoxicity: In the studies I have read, it’s true that the hepatoxic effects of tamoxifen have shown to increase incidents of fatty liver, but only after 12 weeks of continuous administration at the very earliest in otherwise unhealthy patients (breast cancer patients). All hepatocellular carcinomas correlated with tamoxifen use have been seen in patients using such drugs, always in combination with other drugs/therapies, for years.

I have never seen a study on healthy individuals (other than rats), a study that used short periods of time that found true hepatic distress, or a study that was other than correlational in this regard.

It is also worth noting that comiphene DOES NOT have the same level of hepatotoxicity, nor has been shown to be carcinogenic to the liver (nor other tissue, with a POSSIBLE exception of the uterus).

In regards to other cancer (uterine example): AAS users are largely male. While at least one MD has speculated that the prostate may be similarly effected by SERMS as the uterus has been suggested to be, no evidence yet presented supports this speculation.

With the problems present in these studies (not accounting for possible drug interactions, possible immune affectation due to the patients condition, extended duration, correlational nature, lack of controls), we can ONLY say that these studies do not have enough apparent external validity to draw conclusions in regard to AAS users use of SERMS for PCT.

In other words, we can only say that if you are a woman who is ill with breast cancer, and who is using multiple drugs and therapies for long periods of time, SERMS MAY elevate the risk of certain cancers.

In light of other possible issues of SERM use, such as ocular toxicity, up-regulation of progesterone receptors, and these issues already discussed, it’s best to play it safe, but not using these drugs for PCT has its own adverse health effects that one might have to deal with immediately.


My reason for suspecting Clomid is not because of observed problems, but because the fundamental mechanism, which involves attack on DNA, should work the same for the two structures.

Clomiphene isn’t ordinarily used medically for the long-term periods that tamoxifen is. This alone, and fewer animal studies, could account for not having recorded the same things.

For that reason I don’t recommend constant use of Clomid, years on end. I don’t see a reason to fear standard PCT use, at all – lightning strikes are a far greater threat I think.