I am sorry if it mistaken (please comment or suggest an edit to fix) but by chronically I mean as long as the molecule is administered and effective and by permanently I mean after the molecule was administered and effected "permanently".

I understand that tamoxifen is a medication with the following main indications:

  • Prevention and treatment of breast cancer in humans
  • At least a preventive treatment in cases when gynecomastia can start (such as in teenagers with chest pain or people receiving estrogenic (or doubtfully estrogenic) molecules from whatever reason

For a few years, it was never clear to me from any article I tried to read if tamoxifen is only preventive medicine for gynecomastia (of any type) in any of its probably developmental phases or also a cure for at least some cases of lipomastia.

My question

Do Tamoxifen and other similar SERMs reduce chest fat chronically or permanently?

That is to ask; does taking it for enough time (or any described agonist) permanently change the amount of fat cells in the chest and can thus lower lipomastia or similar conditions (further explained below).

Possible derivative questions

  • What do research about male men with breast cancer indicates?

  • What do research about male men with lipomastia or similar situations indicate?

  • What do research about transsexual men (FTM) show?

    • That is to ask; do physicians prescribe this hormone (or any other hormone) for transsexual men as part of breast fat reduction therapy (likely priming a chest reduction surgery)?

1 Answer 1


A double-blind crossover study of placebo and the antiestrogen tamoxifen in ten men with gynecomastia of diverse etiology showed that:

The reduction of breast size was partial and may indicate the need for a longer course of therapy. A follow-up examination was performed in eight out of ten patients nine months to one year after discontinuing placebo and tamoxifen. There were no significant changes from the end of the initial study period except for one tamoxifen responder who developed a recurrence of breast tenderness after six months, and one nonresponder who demonstrated an increase in breast size and a new onset of tenderness after ten months. Therefore, antiestrogenic treatment with tamoxifen may represent a safe and effective mode of treatment for selected cases of cosmetically disturbing or painful gynecomastia.

Another study conducted to explore the effectiveness of tamoxifen in physiological gynecomastia depicted that:

It appears to confirm previous studies that tamoxifen is not only effective with a greater than 80% success rate but also safe. Furthermore, since only one case in our study recurred after stopping tamoxifen, it would indicate the permanent effect of tamoxifen on physiological gynecomastia. In conclusion, we have shown that physiological gynecomastia can be divided into two recognizable forms; fatty and lump gynaecomastia. The overall success rate of tamoxifen to reduce mass and tenderness is high at over 80% for both types, however, the lump form of gynecomastia appears to be completely responsive to this medication. Source

Supporting the promising therapeutic use of tamoxifen in gynecomastia, a new study concluded that:

Tamoxifen, at a daily dose of 20 mg, was administered over 2-4 months to 16 patients with gynecomastia. Of twelve patients with painful gynecomastia ten became pain-free. Gynaecomastia regressed partially or completely in 14 patients, in only 2 was it unchanged. There was no recurrence of gynecomastia after discontinuing tamoxifen

However, in case of management of Pubertal gynecomastia (it is defined as benign breast enlargement occurring during male puberty without evidence of endocrinopathy, underlying disease, or drug effect), better response to raloxifene than to tamoxifen was found in a study

A study reported that the real effect of clomiphene in reducing gynecomastia in 18 of 19 pubertal-adolescent patients is based on several grounds. It is rare to observe a measurable reduction in gynecomastia occurring spontaneously in a period as short as eight weeks, yet this phenomenon was noted in all 18 responders in this series. A recurrence within two months of stopping therapy in three responders implies a definite suppressive effect of the drug. It is noteworthy that no subject showed an increase in gynecomastia during clomiphene therapy. Spontaneous fluctuations in the size of untreated gynecomastia are occasionally seen, but the rapidity, extent, and consistency of the changes we observed with clomiphene treatment argue strongly against the operation of chance events.Link

However, another study concludes that Clomiphene citrate in a dose of 50 mg/day resulted in only small decreases in persistent pubertal gynecomastia and was not a satisfactory medical therapy for the condition.Link







  • Hello, I thank you for the answer --- if I understand correct, if the cause for lipomastia is genetic and not acute --- tamoxifene won't help (excessive fat cells in chest won't degenerate and die and cleaned off the body) so tamoxifen only helps in acute lipomastia but raloxifene might do cause it to happen.
    – user8225
    Jan 22, 2020 at 11:22
  • I further understand that mammary tissue (if exist) will always remain and cannot be destroyed and cleaned off from the body, by any SERM wahtsoever.
    – user8225
    Jan 22, 2020 at 11:23
  • Did I understand correct?... Thanks anyway !
    – user8225
    Jan 22, 2020 at 11:23
  • Genetic causes of gynecomastia are overall quite rare, however, the commonest genetic cause is a condition known as Klinefelter syndrome(KS), which affects about one in every 550 males. Effectiveness of tamoxifen has not been assessed in KS patients so we can conclusively state whether the drug will help or not in this case. Likewise, raloxifene has been found superior only in Pubertal gynecomastia.
    – CCR
    Jan 23, 2020 at 9:57
  • 1
    ok sure. will do.
    – CCR
    Feb 9, 2020 at 5:13

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