Finasteride side effects, safety, risk, danger, adverse reactions
Some finasteride side effects that have been reported include decrease in libido, loss of sensation, impotence or ED, low sperm count, and a decrease in general vitality. Some report sleep problems or insomnia. These occur gradually and in a subtle manner, and many men do not realize it is occurring and forget how they felt before they started finasteride treatment for hair loss or prostate enlargement. Some men feel that life is not as exciting as it used to be and others may even experience low mood or depression. Another adverse reaction may be an increase in abdominal fat (increase in size of the belly).

Users report that its side effects — inability to orgasm, painful erections, chronic depression, insomnia, brain fog, and suicidal thoughts — can last long after patients stop taking the pill.

Curr Opin Endocrinol Diabetes Obesity 2015. Safety concerns regarding 5α reductase inhibitors for the treatment of androgenetic alopecia. To examine the clinical and basic studies regarding persistent adverse effects associated with 5α reductase inhibitor treatment for androgenetic alopecia. Recent postmarketing reports and a US Food and Drug Administration analysis have documented uncommon persistent sexual and nonsexual side-effects in a subset of younger men who have taken finasteride 1 mg for androgenic alopecia. While the mechanisms of the sexual side-effects in humans is incompletely understood, one study found lower cerebrospinal fluid concentrations of dihydrotestosterone, progesterone, dihydroprogesterone and allopregnanolone, and higher levels of testosterone, 5α-androstane-3α,17β-diol and pregnenolone. Another study found up-regulation of the androgen receptor in the human foreskin with a mean of 5 years after finasteride discontinuation. Studies of erectile dysfunction in finasteride-treated rats showed fewer autophagosomes in smooth muscle on transmission electron microscopy, increased apoptosis, decreased smooth muscle, increased collagen deposition and decreased endothelial nitric oxide synthase. Finally, 5α reductase inhibitors have also been found to alter semen parameters in healthy men. Multiple animal studies provide a biological basis for many of the persistent effects seen in humans such as erectile dysfunction, depression and decreased alcohol consumption. Prescribers of 5α reductase inhibitors should discuss the potential risks with their patients seeking treatment for androgenetic alopecia.

Erectile dysfunction, impotence, loss of libido or sex drive
Some people find that the libido reducing effects from short term use are reversed within several weeks after stopping the medication. Some individuals like to reverse it quicker with the use of certain libido boosting herbal products, for instance Passion Rx or other natural aphrodisiac herbs. In most men who develop persistent sexual side effects longer than 3 months despite the discontinuation of finasteride, the sexual dysfunction continues for many months or years.

Men with the most common form of baldness who take this drug are more likely to experience an increase in hair count, and say they believe their hair is thicker. But some also experience erectile dysfunction or impotence.

Horm Mol Biol Clin Investig. 2015. Finasteride, not tamsulosin, increases severity of erectile dysfunction and decreases testosterone levels in men with benign prostatic hyperplasia.

Am J Mens Health. 2014 . Persistent Sexual, Emotional, and Cognitive Impairment Post-Finasteride: A Survey of Men Reporting Symptoms. Finasteride is a synthetic 5-α reductase inhibitor, which prevents the conversion of testosterone to dihydrotestosterone and has been used for more than 20 years in the treatment of male pattern hair loss. Randomized, controlled trials have associated finasteride with both reversible and persistent adverse effects. In this pilot study, we sought to characterize sexual and nonsexual adverse effects that men reported experiencing at least 3 months after stopping the medication. Based on previous research on persistent side effects of finasteride, we constructed an Internet survey targeting six domains: physical symptoms, sexual libido, ejaculatory disorders, disorders of the penis and testes, cognitive symptoms, and psychological symptoms and was e-mailed to patients who reported experiencing symptoms of side effects of finasteride. Responses from 131 generally healthy men (mean age, 24 years) who had taken finasteride for male pattern hair loss was included in the analysis. The most notable finding was that adverse effects persisted in each of the domains, indicating the possible presence of a "post-finasteride syndrome."

Expert Opin Drug Saf. 2013. Effects of 5-alpha reductase inhibitors on erectile function, sexual desire and ejaculation. Treatment with 5-alpha reductase inhibitors (5ARI) is commonly utilized for the treatment of benign prostatic hyperplasia (BPH). The true prevalence of sexual side effects with 5ARI treatment is currently unknown. Clinical trials with 5ARI report decreased circulating dihydrotestosterone (DHT) associated with diminished sexual desire and/or orgasm. The presence of adverse sexual effects is associated with decreased self-esteem, quality of life and ability to maintain an intimate relationship.

Use of dutasteride (Avodart) and finasteride (Proscar and Propecia) were linked to erectile dysfunction, depression and loss of libido in a review of existing studies. In a small percentage of cases, symptoms persisted even after the medication is stopped. For those men, "it's a life sentence. No sex. No desire. Potential depression," said researcher Abdulmaged M. Traish, a professor of biochemistry and urology at Boston University School of Medicine.. Almost everyone who takes these drugs experiences some of these side effects but, some experience it more drastically than others. "We need androgen for erectile function, libido and ejaculation, and for just feeling good," Abdulmaged Traish said., noting that increasing numbers of patients report ongoing sexual problems after they stop taking the drugs. Published in the March 2011 issue of the Journal of Sexual Medicine.

Reading the article about finastride and it definitely reduces sensation in the genital organs. I noticed this and was glad to see that another user noticed it. It also reduces libido but fortunately mine is high enough that it is not uncontrollable. Avodart was worse and I had to stop taking.

Can I take Passion Rx whilst I am on finasteride for hair loss? Is it going to effect my hair loss treatment or is it going to be a okay cause I need something to help with finasteride induced low libido.
    If your doctor approves you can take them together. This libido formula should not have an effect on hair loss or growth.

Testimonials
I have had some side-effects e.g. erectile problems, libido issues, lethargy, constantly dozing off at any time of the day etc., after taking this prostate medication for one year.

Q. I am suffering side effect from finasteride and my blood test shows that I have low testosterone and low normal estradiol. I have ED and broken sleep patterns. And I read through some post that saying pregnenolone could help with these symptoms. Do you know if I have low estrodial/estrogen, is pregnenolone going to help with it?
   A. This hormone could help but it could also potentially cause hair loss in some users and in high doses cause sleep problems.

Depression side effect
Finasteride induced depression: a prospective study. BMC Clin Pharmacol. 2006.
The purpose of this study was to examine whether depressive symptoms or anxiety might be induced by finasteride administration. One hundred and twenty eight men with androgenetic alopecia, who were prescribed finasteride (1 mg/day) were enrolled in this study. Information on depressed mood and anxiety was obtained by Beck Depression Inventory, and Hospital Anxiety and Depression Scale. This preliminary study suggests that finasteride may cause depression; therefore this medication should be prescribed cautiously for patients with high risk of depression.

My husband started taking finasteride Propecia and I started to notice a change in him right away looking back now in hindsight., He was tired and fell asleep more often when putting kids to bed. Had no real gusto for life that he used to have. Are there natural pills to take to help with improving mood?
   See natural treatment options for treating depression.

I had been taking finasteride (1-2 mg/day) for several years but recently stopped when I began to suspect it was causing depression, panic attacks, and cognitive disorders (mental fog). It had only a marginal effect on hair regrowth. I have not had any sexual dysfunction related side effects, only depression, the mental fog, and a general discomfort in social settings (I developed an intense desire to be alone). I did not experience these sensations previously in my life. I am a male aged 41 and in good health. I do not take other prescription drugs.

Robin Williams, the comedian, was on finasteride. I wonder whether this contributed to his depression. Robin Williams may also have been prescribed Rapaflo, mirtazapine, and quetapine.

Testimonial regarding low mood and depression
I have a son who started losing his hair at age 14. We met with multiple doctors to rule out underlying medical reasons for the condition. Nothing identified except for just early balding. He started on finasteride in high school and is still using that. He has had some unexplained depression, suicidal thoughts and insomnia. We haven’t asked about libido and those related issues. I’m not sure how much good the drug is doing for my son and I’m very concerned about the possible side effects, especially if they are well documented.

JAMA Intern Med. 2017. Association of Suicidality and Depression With 5α-Reductase Inhibitors. There have been concerns raised by patients and regulatory agencies regarding serious psychiatric adverse effects associated with 5α-reductase inhibitors. In a large cohort of men ages 66 years or older, we did not demonstrate an increased risk of suicide associated with 5α-reductase inhibitor use. However, the risk of self-harm and depression were increased compared with unexposed men.

Low sperm count
Finasteride induced spermatogenic failure: A report of two cases.
Fertility Sterility 2007.
Two patients with azoospermia and severe oligospermia using finasteride 1 mg for hair loss. Patient A had documented azoospermia over 1 year and was initially booked for a testicular biopsy. Six months after discontinuation of finasteride 1 mg daily he showed improvement in sperm concentration to 5.5 x 10(6)/mL. Patient B had severe oligospermia with a sperm concentration of 4 x 10(6)/mL. Sperm concentration improved to 6.6 then 18.7 x 10(6)/mL at 3 and 6 months after stopping finasteride.

Muscle damage
Finasteride-induced myalgia and HyperCKemia.
J Clin Neuromuscul Dis. 2008.
We report a case of finasteride-associated myalgia and hyperCKemia and review similar cases reported in the literature. A 30-year-old man who had been taking finasteride 5 mg/d for 10 years to treat frontal baldness developed diffuse muscle aches associated with elevated creatine kinase level to 10,117 IU/L with neither weakness nor pigmenturia. His symptoms resolved and his creatine kinase level dropped down to 256 IU/L 3 weeks after finasteride discontinuation. Reversible myalgia associated with significant hyperCKemia is a possible adverse reaction of finasteride therapy.

I'm a 30 years old male who has been taken Propecia (finasteride for hair loss) during 5 years. I play indoor football, and in the last 3 years I have suffered several muscular injuries while playing a match, always alone (not oponent agressions or bad movements). I would like to ask if it does make sense that this has a relation with the ingest of the hair medication.
   It's difficult to say.

Benefit for prostate gland enlargement
I am currently taking finasteride Proscar 5 mg, do I need to reduce my dose if I am taking Prostate Power Rx?
   Perhaps you will need less of a dose but your doctor is the person who makes the final decision since he or she prescribed the finasteride and knows your condition best. You will only know for certain after you take them for a few weeks or months and then try to reduce your dose of the medication to see if the lesser dose is still effective.

Finasteride masks PSA test for prostate cancer
Proscar is used for prostate enlargement and contains 5 milligrams of finasteride while Propecia has 1 mg. Finasteride apparently artificially lowers a protein called prostate specific antigen (PSA). High levels of PSA in the blood can signal prostate cancer or other problems. Dr. Anthony D'Amico, the lead author of the study from Brigham and Women's Hospital in Boston, recommends that middle-aged men taking finasteride have their PSA levels multiplied by two in tests to account for the difference. Merck said in a statement that the study results were first presented in 2000 and are "consistent with information that has been included in the label for Propecia (finasteride 1 mg) since the product was first approved in 1997. In an earlier trial of a drug called Proscar, which contains a higher dose of finasteride, PSA levels were also lowered as well as the risk of prostate cancer. But men taking Proscar who developed cancer had a more aggressive disease. D'Amico and Dr. Claus Roehrborn, of the University of Texas Southwestern Medical Center in Dallas, studied the impact on PSA levels on 355 men ages 40 to 60 years old who took finasteride for one year. The research was funded by Merck and the findings are reported in the journal Lancet Oncology.

Effect of 1 mg/day finasteride on concentrations of serum prostate-specific antigen in men with androgenic alopecia: a randomised controlled trial.
Lancet Oncol. 2007G. Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Faber Cancer Institute, Boston, MA, USA.
Use of 5 mg/day finasteride for benign prostatic hyperplasia is known to affect serum concentrations of prostate-specific antigen PSA. When men taking this treatment undergo screening for prostate cancer, a compensatory adjustment of the PSA concentration (to multiply the value by two) is recommended. Whether this recommendation should apply to men taking 1 mg a day finasteride ( Propecia ) for the treatment of androgenic alopecia is unknown. We aimed to assess the effect of 1 mg/day finasteride on serum PSA in men aged 40-60 years with male-pattern hair loss. Within 48 weeks of randomisation, had a median decrease in serum PSA concentration of 40%. The existing recommendation for the adjustment of serum PSA concentration in prostate-cancer screening in men taking 5 mg a day finasteride should also apply to men taking the 1 mg/day preparation for male-pattern hair loss.

To prevent or reduce prostate cancer risk?
In 2009, the American Society of Clinical Oncology and American Urological Association said medical studies show the risk of prostate cancer drops by about 25 percent among men taking finasteride since it lowers the level of a hormone that can contribute to the growth of prostate cancer. Dr. Barnett Kramer, a disease prevention specialist at the U.S. National Institutes of Health and co-chairman of the panel that drafted the recommendations, said taking the drug to prevent the disease could cost more than $1,000 a year. Dr. Barnett Kramer said 71 men would need to take the drug for 7 years for one of those men to avoid getting prostate cancer.
   Comments by Dr Sahelian: Finasteride may reduce the risk of prostate cancer, but it causes sexual dysfunction including reduced libido and problems with maintaining erections. Reducing quality of life by taking it has to be balanced with the potential decrease in prostate cancer risk. The reduction of this risk is not yet fully proven.

Finasteride and women
When given in combination with oral contraceptives, finasteride can improve female-pattern hair loss in most women. At present, the main treatment for female-pattern hair loss is topical minoxidil, which is somewhat effective. Whether treatment with agents such as finasteride, which show activity against male hormones, might promote hair growth in women has been unclear. However a research group reports in Archives of Dermatology, March 2006, that women with female-pattern hair loss who were treated with finasteride in combination with an oral contraceptive did report benefits. Finasteride has been linked to birth defects and that was the reason the women were given birth control pills. After 12 months of finasteride therapy, and out of 37 women treated, hair growth improvements were rated as "great" in three patients, "moderate" in eight and "slight" in twelve women. Thirteen women had no improvement and one patient experienced a worsening of her female-pattern hair loss.

Avodart versus finasteride, which to choose?
Both Avodart and finasteride are available to treat an enlarged prostate. I am not sure which drug is better. Both can also treat male pattern hair loss.

The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride.
J Am Acad Dermatol. 2006.
Male pattern hair loss is a potentially reversible condition in which dihydrotestosterone is an important etiologic factor. Our aim was to evaluate the efficacy of the type 1 and 2 5alpha-reductase inhibitor dutasteride in men with male pattern hair loss. Four hundred sixteen men, 21 to 45 years old, were randomized to receive dutasteride 0.05, 0.1, 0.5 or 2.5 mg, finasteride 5 mg, or placebo daily for 24 weeks. Dutasteride increased target area hair count versus placebo in a dose-dependent fashion and dutasteride 2.5 mg was superior to finasteride at 12 and 24 weeks. Dutasteride increases scalp hair growth in men with male pattern hair loss. Type 1 and type 2 5alpha-reductase may be important in the pathogenesis and treatment of male pattern hair loss.

Acne benefit
Effect of finasteride 5 mg (Proscar) on acne and alopecia in female patients with normal serum levels of free testosterone.
Gynecol Endocrinol. 2007. Division of Gynaecological Endocrinology and Reproductive Medicine, Department Ob/Gyn, University of Berne. Berne. Switzerland.
In some women with acne or alopecia who have normal serum levels of free testosterone, no clinical improvement can be reached by the classical treatment with antiandrogens, isotretinoids or corticosteroids. Our hypothesis is that some of these women have an excessive activity of the enzyme 5alpha-reductase. We evaluated the subjective benefit of the treatment with finasteride (5 mg/day) in women with normal serum levels of free testosterone suffering from acne or alopecia. This was a retrospective study evaluating a questionnaire filled out by 12 patients, six of whom had acne and six of whom had alopecia. Nine of the 12 patients benefited from the finasteride treatment, their symptoms decreased significantly and they felt better psychologically than before the administration of finasteride. The other three patients did not benefit at all. Treatment was generally well tolerated, only a few adverse effects were noted. This supports our hypothesis of an excessive activity of 5alpha-reductase enzyme in peripheral tissue in these patients. The fact that three of the patients did not realize any change in their symptom severity implies that there must also be other pathways in the genesis of acne and alopecia in women with normal levels of free testosterone.

Use in priapism
Those with recurrent excessive engorgement of the penis for several hours, called priapism, may benefit from this medication.

Alcohol intake
Many men on finasteride have less of an urge to drink alcohol perhaps because this medication interferes with the making in the brain of neurosteroids.

Dogs, pets, animals
Theriogenology. 2018. Effects of benign prostatic hyperplasia and finasteride therapy on prostatic blood flow in dogs. BPH is characterized by an enlargement of the prostate with an increase in prostatic blood perfusion and vascularization. Finasteride treatment reduces simultaneously the volume, local vascularization and blood flow of the prostate.

Questions
Q. Do you think finasteride decreases sensation of the nerves in the body? Ever since I started taking it for hair growth, I think that skin, nipples, genital organ, just don't seem to be as sensitive. This medication is helping regrow hair, so I am happy about that, but I just don't feel as alive. I'm not sure but I think my vision is not as clear.
   A. This is an interesting observation and perhaps it does have something to do with neural sensation being decreased but since we have not seen research on this topic and we have not had other people mention this yet, perhaps it is a subtle finasteride side effects, we can't say for sure.

Q. I have read in some journal at one time that finasteride Proscar acts like a SSRI and can lead to increased serotonin especially in the GI tract. I have taken finasteride Proscar for about twenty years and have IBS and am wondering if there is a correlation.
   A. Finasteride blocks testosterone conversion to DHT. I can't imagine any close relation of this effect with blocking the uptake of serotonin. Finasteride use could lead to low mood, low vitality, and possible depression in some users. I have not seen any direct connection between finasteride and irritable bowel syndrome.

Q. Firstly, I very much enjoyed reading the information on your web page. I would very much appreciate an answer to the following question as I had been considering beginning taking a 50mg supplement of DHEA either every day or every other day. I have been taking 1mg finasteride medication for the past 4 years for male pattern baldness and have had pretty good results both in maintaining and regrowing new hair. However, I have noticed over the past 12 months that despite no real change in my diet or exercise plan that I have begun to slowly put weight on around the middle waist and have almost totally lost interest in sex. My erections are far less frequent and less long-lasting. I also get tired very easily. I have recently started taking finasteride only every other day to see if that makes a difference, but so far no visible sign! According to the "hype" DHEA would seem to be the perfect answer. More energy, increase in lean muscle, decrease in fat and increased libido. Having read you articles on DHEA, I am now worrying about DHEA side effects...not least the potential for my hair to fall out!! Do you think that keeping it to a low'ish dose every other day maybe when I take finasteride medication and then stopping after 3months...waiting a month and then doing another 3 month cycle should be ok?
   A. DHEA use can cause hair loss which counteracts the benefit of hair growth from finasteride. There are natural herbs that improve sexuality and libido, along with erectile function, and these are safer than DHEA hormone use and are not likely to influence hair loss.

Q. I've been taking finasteride for more than a year for enlarged prostate. During this time, I have had the normal loss of libido, erectile dysfunction and more recently a strong rigidness (not elastic as before) in the penis during erection that causes the penis to curve. It is a bit uncomfortable in this state and almost useless. My consideration is to quit taking finasteride but wanted to check to see if this is a known side effect to taking it.
   A. Loss of libido and impotence are common, but I am not sure whether curving of penis is related to finasteride medication use.

Q.  I came across your website when doing research to see if some of my recent symptoms could be caused by the finasteride use of my husband. He started taking the medication about 3 months ago for his hair loss. I am currently using birth control and have been for a long time now. We were aware of the possible birth defects in fetus' that can be caused by finasteride use, but I am wondering if it can cause other side effects as well. I have been having severe headaches since about maybe a month after he started taking the drug. I have also been noticing a heightened growth of hair in myself as well. I have missed my last period and am 2 days into missing this months by the way the birth control pills are set. i have taken a pregnancy test and it shows negative. I steer clear of the drawer that the medication is kept in, as well as never handling the bottle pills, or the pill cutter that he uses. Could the transfer of the medication through my husbands semen be causing these possible finasteride side effects? Any information you would be able to share with me would be most helpful in trying to resolve my unknown symptoms.
   A. This is a very interesting question but beyond my range of knowledge. I am not familiar with research regarding the transfer of finasteride through semen and it's potential effects in a woman. You may wish to contact Merck to see if they have gathered any such information.

Q. I've been on this drug for 7 weeks and I do not notice any sexual or physical side effects at all. However, I do notice one mental side effect -- tripping over words. Normally, when I spoke before taking finasteride medication, it was usually pretty fast, witty, and it came across very smoothly. I never thought about speaking. Now, I seem to be thinking much more and I'm tripping over words. Also, I don't seem to come up with dry humor as quickly. Interesting, I also started drinking a lot of soymilk since starting finasteride as well as using saw palmetto / pygeum, and soy protein powder. I also stopped regular milk intake. I'm at a crossroads here. It seems I have to choose between hair loss and speech.  If I stop finasteride, will the side effects go ahead completely? Also theoretically, if I was taking it for 15 years, would the side effects go away completely if stopped then?
   A. It is possible that a finasteride side effect could include memory or cognitive impairment due to disruption of optimal testosterone / DHT function in brain tissue. I suspect this would reverse completely if stopped after only a few weeks of use, but my best guess is that some finasteride side effects would persist if this product is taken for more than a decade or two.

I suffered from severe anxiety about 6 months after I started taking 5 mg Proscar for prostatitis. I thought going off thyroid hormone caused my anxiety, but now I realize that taking finasteride may have been the main factor in my having the extreme and prolonged anxiety. I read your article and thought you might be interested in evidence indicating that this medication might induce anxiety.
    Thyroid hormone is much more likely to cause anxiety than finasteride, but it is not easy to know what occurred in your case.

I am raging that my doctor who prescribed me finasteride, while mentioning the erectile disfunction possibility, failed to mention the possibility of depression (mind you, I find this morning that if I'd simply googled side effects I could have quite easily found out!). I was prescribed finasteride 6 months ago, 3 months ago I started to (for the first time in my life) suffer anxiety, my relationship with my girlfriend has been on the tether due to a range of issues none of which existed ever before in our 3 year relationship, and in the last 2 weeks I have, amoungst other things, felt like I've been walking around with a brick in my stomache (bad feeling / thought type feeling), have broken down in front of both my direct report manager and his manager on seperate occasions (I'm an engineer so this is quite embarrasing) and as of last night (and final straw) would randomly burst in to tears while having a great time with my friends. I do have a family history of depression although have been the one member who has been blessed enough to avoid it however as of my research this morning I'm stopping taking the drug and well. I'll send an appology email in a fortnight if my radical symptoms persist but if you know anyone who could use this information for any purpose I'd like you to pass it on because my quality of work has been completely destroyed over the last few months - work, relationship, social life, interest in life in general, and I would hate for anyone else to go through what I have been (am right now) going through. Like I said, if this doesn't go away though well, sucks to be me.