Does Effexor cause breast enlargement? (3+ factors)

In this article, we will discuss whether Effexor causes breast enlargement, what research suggests, how Effexor causes breast enlargement, what factors contribute to Effexor-induced breast enlargement, and what to do if you are concerned about Effexor-induced breast enlargement.

Does Effexor cause breast enlargement?

Yes, Effexor may cause breast enlargement, but this is not a listed side effect of Effexor. However, some people reported enlarged breasts while using Effexor, as individual responses to this medication can vary.

Effexor is a serotonin-norepinephrine reuptake inhibitor and works by blocking the reuptake of serotonin and norepinephrine in the brain. It is mainly used to treat depression and anxiety disorders but also has some off-label uses, like obsessive-compulsive disorder. (1)

How does Effexor cause breast enlargement?

The exact mechanism by which Effexor may cause breast enlargement is not well understood. Effexor works by increasing the levels of serotonin and norepinephrine in the brain and doesn’t typically directly impact breast tissue.

However, some studies suggest that this breast enlargement rapidly reduces when the patient is taken off Effexor. Hormonal fluctuations and changes in water retention may also cause breast enlargement, but more research is required to establish a clear connection. (3)

What does research suggest?

Several studies have investigated the association between Effexor and breast enlargement. A study published in the “Journal of Affective Disorders” in 1996 found that among women taking Effexor, approximately 39% reported breast enlargement as a side effect. (2)

Effexor inhibits the reuptake of serotonin and norepinephrine; at lower doses, it acts as a selective serotonin reuptake inhibitor, and its chronic use can cause breast enlargement. Another case in clinical neuropharmacology in 2009 reported similar findings: A young patient experienced breast changes while on Effexor. (3,4)

However, the researchers acknowledged that more research is needed to determine whether Effexor was the sole contributor to this side effect.

What are the factors contributing to Effexor-induced breast enlargement?

Several factors can contribute to effexor-induced breast enlargement.

  • Individual factors: Individual factors, such as genetics, underlying health conditions, and individual variation in metabolism, may play a role in determining whether someone experiences breast enlargement while taking Effexor. It’s important to emphasize that people respond differently to this medication, and what may affect one individual may not affect another.


  • Hormonal balance: Balanced hormones are necessary for regulating the growth and development of the body. Disturbances in these hormones can result in a wide range of health issues, including the enlargement of breasts.


  • Dosage and duration: Dosage and duration affect how the body will respond to a certain medication. Taking Effexor in high doses and for an extended period can also increase the risk of breast enlargement associated with it. (4)

What other hormonal changes can occur due to Effexor?

Effexor affects the levels of serotonin and norepinephrine in the brain, but it can also have secondary effects on other hormones in the body. It’s important to note that individual responses to medications can vary, and not everyone will experience the same side effects. Here are some potential hormonal changes associated with the use of Effexor:

  • Cortisol: The adrenal glands produce the hormone cortisol in response to stress, and long-term use of antidepressants, such as Effexor, may have an impact on cortisol regulation. Changes in cortisol levels can impact the body’s stress response. (7)


  • Sex hormones: Antidepressants like Effexor may affect the levels of estrogen and testosterone. This can lead to changes in libido, sexual function, and menstrual cycles, particularly in women. (5)


  • Prolactin: Studies suggest that Effexor can increase prolactin levels. Prolactin is a hormone that plays a role in breastfeeding. (8)


  • Thyroid function: While the direct impact of Effexor on thyroid hormones is not well-established, it can affect thyroid functions like metabolism and energy regulation. (6)

If you are experiencing changes in mood, energy levels, or any other symptoms that may be related to the hormonal effects of Effexor, consult with your healthcare provider so they can address your concerns.

What to do if you are concerned about Effexor-induced breast enlargement?

If you are taking Effexor and are concerned about the possibility of breast enlargement, it’s crucial that you openly talk to your healthcare provider. They can provide personalized information based on your medical history and current symptoms and may suggest adjustments to your treatment plan.

If adjusting the dose does not resolve the issue, your doctor might consider an alternative antidepressant other than Sertraline, as it may also cause breast enlargement, to reduce the symptoms.

However, it is important to note that not everyone will experience this symptom, so never discontinue or adjust your medication without consulting your healthcare professional, as abrupt changes can have adverse effects on your mental health.


According to the research and my knowledge of the topic, the evidence of Effexor-induced breast enlargement is inconclusive. Individual responses vary, and factors beyond the medication may contribute to this change. It is crucial to consult with your healthcare provider to make informed decisions about your mental health treatment.

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Singh D, Saadabadi A. Venlafaxine. [Updated 2022 Oct 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:


Amsterdam JD, Garcia-España F, Goodman D, Hooper M, Hornig-Rohan M. Breast enlargement during chronic antidepressant therapy. J Affect Disord. 1997 Nov;46(2):151-6. doi: 10.1016/s0165-0327(97)00086-4. PMID: 9479619.


Karakurt F, Kargili A, Uz B, Kaya A, Kosar A, Ozkara A, Ozbek M. Venlafaxine-induced gynecomastia in a young patient: a case report. Clin Neuropharmacol. 2009 Jan-Feb;32(1):51-2. doi: 10.1097/WNF.0B013E3181679126. PMID: 18978497.


Altieri MA, da Silva AS, da Silva Moreira S, Zapaterini JR, Arena AC, Barbisan LF. Safety of lactational exposure to venlafaxine on the rat mammary gland development and carcinogenesis in F1 female offspring. Reprod Toxicol. 2023 Sep;120:108451. doi: 10.1016/j.reprotox.2023.108451. Epub 2023 Jul 31. PMID: 37532207.


Pavlidi, P., Kokras, N., & Dalla, C. (2021). Antidepressants’ effects on testosterone and estrogens: What do we know? European Journal of Pharmacology, 899, 173998.


Eker, S. S., Akkaya, C., Sarandol, A., Cangur, S., Sarandol, E., & Kirli, S. (2008). Effects of various antidepressants on serum thyroid hormone levels in patients with major depressive disorder. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 32(4), 955-961.


Araya AV, Rojas P, Fritsch R, Rojas R, Herrera L, Rojas G, Gatica H, Silva H, Fiedler JL. Early response to venlafaxine antidepressant correlates with lower ACTH levels prior to pharmacological treatment. Endocrine. 2006 Dec;30(3):289-98. doi: 10.1007/s12020-006-0007-2. PMID: 17526941.


Impacts of a six-month venlafaxine intake on serum prolactin levels in patients with major depressive disorder, Alper Evrensel, Adnan Cansever, Ufuk Hamurcu, Murat Oncu, Psychiatry and Clinical Psychopharmacology 2015; 25: Supplement S159-S160

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