
Finasteride has been prescribed to millions of men worldwide to treat hair loss and benign prostatic hyperplasia. It's a medication that can have a significant impact on a man's life, but it's not without risks.
Some of the most concerning side effects of finasteride include infertility and erectile dysfunction. According to the article, 1 in 5 men who take finasteride experience persistent erectile dysfunction. This is a serious issue that can have long-term effects on a man's quality of life.
The risk of infertility is also a major concern. Studies have shown that finasteride can decrease testosterone levels, which can affect sperm count and fertility. In fact, one study found that finasteride reduced sperm count by 40% in some men. This is a serious side effect that can have a lasting impact on a man's reproductive health.
Men who are considering taking finasteride need to be aware of these risks and weigh them against the potential benefits.
Risks and Side Effects

Taking finasteride can impair ocular function and cause dry eye disease, with significant reductions in tear flow and tear film break up time.
Finasteride-treated rats showed a 49% reduction in tear flow and a 29% reduction in tear film break up time, while finasteride-treated male rats experienced a 40% reduction in tear flow and a 63% reduction in tear film break up time.
Finasteride can also induce severe inflammation of the lacrimal gland, with significant increases in lymphocyte infiltration and histopathologic changes in the gland.
The risk of developing Post-Finasteride Syndrome (PFS) is a concern, with 18,200 people experiencing adverse effects related to finasteride and 89 reported suicides worldwide to date.
PFS can be characterized by psychological symptoms that can lead to suicide, and it's not just limited to finasteride use - dutasteride and other DHT blockers can also cause PFS.
Dutasteride and Insulin Resistance
Dutasteride has been linked to decreased insulin sensitivity in peripheral organs, including skeletal muscle and adipose tissue.

Studies have shown that men treated with dutasteride exhibit impaired insulin sensitivity, which may be mediated by impaired glucose disposal in muscle.
Men receiving dutasteride have increased fasting plasma C-peptide and homeostatic model assessment of insulin resistance and increased plasma insulin levels.
Dutasteride treatment can lead to increased blood glucose, glycosylated hemoglobin A, total cholesterol, and low-density lipoprotein cholesterol levels.
Long-term dutasteride therapy can induce imbalance in metabolic function, as suggested by increased activities of liver alanine aminotransferase and aspartate aminotransferase.
A study found that dutasteride resulted in a modest increased risk of type 2 diabetes compared to tamsulosin, with an adjusted hazard ratio of 1.34.
However, another study found that men treated with 5α-RIs, including dutasteride, had a lower cumulative rate of type 2 diabetes compared to those not treated with 5α-RIs.
Dutasteride Impairs Ocular Function
Dutasteride, like finasteride, can significantly impair ocular function and cause the development of dry eye disease. In fact, studies have shown that dutasteride administration downregulates androgen receptors in the lacrimal gland, leading to a reduction in tear production and evaporative dry eye conditions.
Finasteride administration significantly downregulated androgen receptors in the lacrimal gland, which is similar to dutasteride's effect. This reduction in androgen receptors leads to a decrease in tear flow and tear film break up time.
Tear flow was reduced by 49% in female rats and 40% in male rats after finasteride treatment. Dutasteride likely has a similar effect on tear flow.
In rats treated with finasteride, the tear film break up time (TBUT) was reduced by 29% in females and 63% in males. This is a concerning side effect, as it can lead to dry eye disease.
Finasteride treated rats showed significant reductions in TBUT and tear flow, similar to dutasteride's effects. These reductions are likely due to the lack of 5α-DHT in the lacrimal glands.
The effects of dutasteride on ocular function are concerning, especially when considering the potential for dry eye disease.
What?
Finasteride is not an immediate fix, it typically starts working about 3 months after taking the medication.
Most men can take finasteride safely for either BPH or pattern hair loss, but both the 5-milligram and 1-milligram doses come with a small risk of unpleasant and sometimes serious side effects.
Finasteride can also be useful for hair loss in women, but this would be an off-label use as this medication is not yet FDA-approved for this purpose.
A study of male Japanese finasteride users found that the drug improved hair growth in 87.1 percent of men up to 70 years of age.
Common Risk Factors for Hair Loss
Hair loss can be caused by a combination of factors, including family history, hormones, stress, illness, and certain medical conditions. It's a common issue that can affect anyone.
A family history of hair loss can increase your risk of experiencing it yourself. If your parents or grandparents have experienced hair loss, you may be more likely to do so as well.
Hormonal imbalances, particularly high levels of androgens, can also contribute to hair loss. This is why some people experience hair loss during puberty or menopause.
Stress can cause hair loss, especially if it's prolonged or severe. I've seen friends experience hair loss after going through a tough time in their lives.
Certain medical conditions, such as thyroid disease, lupus, and diabetes, can increase your risk of hair loss. If you have any of these conditions, it's essential to work with your doctor to manage them effectively.
Here are some of the common risk factors for hair loss:
- Family history (heredity)
- Hormonal imbalances (e.g. high levels of androgens)
- Stress
- Certain medical conditions (e.g. thyroid disease, lupus, diabetes)
- Certain medications (e.g. chemotherapy drugs, blood thinners)
Some hair loss can also be caused by certain cosmetic procedures, such as shampooing too often, using hot curlers, or getting perms. Be gentle with your hair to minimize the risk of damage.
A low-protein diet or severely calorie-restricted diet can also contribute to hair loss. Eating a balanced diet that includes plenty of protein can help keep your hair healthy.
Post-Syndrome
Post-Finasteride Syndrome (PFS) can occur after taking finasteride, but it's not exclusive to this medication. It can also happen to people who take dutasteride or use other DHT blockers.
The psychological symptoms associated with PFS are serious and can lead to suicide. Currently, there have been 89 reported suicides worldwide related to finasteride.
People with PFS may have changes in their genetic expression that contribute to erectile dysfunction. These changes are thought to be a partial cause of the risk of developing PFS.
The risk of developing PFS may be partially genetic, but it's not the only factor at play.
Dutasteride
Dutasteride has been linked to increased risk of type 2 diabetes in men, particularly those taking 0.5 mg/d for lower urinary tract symptoms (LUTS) secondary to BPH. This was observed in a study of 230 men who were followed-up for 36 to 42 months.
The risk of developing type 2 diabetes was higher for men taking dutasteride compared to those taking tamsulosin, with an adjusted hazard ratio (HR) of 1.34. Dutasteride also increased blood glucose, glycosylated hemoglobin A, total cholesterol, and low-density lipoprotein cholesterol levels.
Additionally, dutasteride has been shown to impair insulin sensitivity in peripheral organs, including skeletal muscle and/or adipose tissue. This impairment may be due to impaired glucose disposal, mainly in muscle where 5α-R types 1 is expressed.
What Is It and How Does It Work?
Finasteride is a prescription drug that works by reducing the enzyme 5-alpha-reductase, which creates DHT, a hormone that contributes to male pattern baldness.
DHT causes hair follicles to shrink, leading to fewer hairs being produced. Each hair follicle can produce anywhere from one to five hairs.
The follicles on the top and crown of the head tend to contain DHT-sensitive follicles, making it common for male pattern baldness to start with a receding hairline or thinning hair at the crown.
Reducing the 5-alpha-reductase enzyme means the drug is essentially eliminating the cause of hair loss in the first place.
It takes some time before the effects of finasteride become noticeable, typically around six months, but it could take up to one year.
Stopping the medication will result in increased production of the 5-alpha-reductase enzyme again, leading to additional DHT production and hair loss.
Finasteride is most effective in the early stages of male pattern baldness, when a large number of hairs remain, and is generally accepted as the most effective non-surgical treatment for male pattern hair loss.
It's most successful when used in the early stages, and men who tend to respond most impressively to finasteride are typically in their 20s and 30s.
However, older men can still experience significant slowing or even a degree of reversal of their hair loss.
Finasteride works by blocking an enzyme that converts testosterone into DHT, which binds to hair follicles on the scalp, causing them to shrink and eventually stop producing hair.
DHT is the main hormone responsible for androgenetic alopecia, a type of hair loss that affects many men.
Finasteride is a competitive and specific inhibitor of type II 5 alpha-reductase, which is found in hair follicles and contributes to the miniaturization of hair follicles.
By inhibiting this process, finasteride can lead to the reversal of the balding process.
In clinical trials, finasteride has shown to stop the progression of hair loss in 86% of participants and increase hair growth in 65% of participants.
It's most effective in those with mild to moderate hair loss, and the effects will barely be noticeable if the person has lost too much hair.
Pharmacokinetic Profile of
The pharmacokinetic profile of dutasteride is quite interesting. It has a half-life of approximately 3-4 weeks, which means it stays in the body for a relatively long time.
After oral administration, dutasteride is absorbed into the bloodstream, with peak plasma concentrations reached in about 2-3 days. This slow absorption rate contributes to its long half-life.
Dutasteride is extensively metabolized in the liver, with less than 2% of the dose excreted unchanged in the urine. This extensive metabolism reduces the risk of accumulation and toxicity.
The bioavailability of dutasteride is around 80-90%, indicating that a significant portion of the administered dose is available to the body. This high bioavailability contributes to its effectiveness in treating benign prostatic hyperplasia (BPH).
Propecia and Hair Loss
Propecia, the brand name for finasteride, is a pill that interferes with the production of a form of testosterone that's linked to baldness. It's been shown to be effective in slowing down hair loss and even regrowing some of the hair that's already been lost.
Finasteride is most effective in men with mild to moderate hair loss, and it's been proven to be more effective in year five of use than in year one. In fact, clinical trials have shown that the progression of hair loss stopped in 86% of participants, and 65% experienced a substantial increase in hair growth.
The medication works by blocking an enzyme called 5-alpha reductase, which converts testosterone into dihydrotestosterone (DHT). DHT is the main hormone responsible for androgenetic alopecia, also known as male or female pattern baldness.
Here's a breakdown of how finasteride works:
- Blocks 5-alpha reductase enzyme
- Reduces production of DHT
- Slows down hair loss and promotes regrowth
It's worth noting that finasteride is not approved for use in women, and it's a Category X drug for pregnancy risk, meaning it can cause birth defects.
Propecia Development
Finasteride, the active ingredient in Propecia, was originally developed to treat enlarged prostate glands. Merck created a medication called Proscar in 5mg doses for this purpose.
The medication, Proscar, was already approved by the FDA, and during clinical trials, participants reported a fortunate side effect: additional hair growth.
This led Merck to repurpose the drug and create the first hair loss medication in a pill form, which became Propecia in 1997.
Propecia was approved by the FDA in 1997 for treating male pattern baldness, and it remains a popular treatment for androgenic alopecia today.
The 1mg dose of finasteride was specifically developed for Propecia, making it a unique treatment for hair loss.
Here's a brief timeline of Propecia's development:
- 1990s: Merck develops Proscar (5mg finasteride) for enlarged prostate glands.
- 1997: Clinical trials reveal hair growth as a side effect.
- 1997: Propecia is approved by the FDA for treating male pattern baldness.
Women's Hair Loss
Finasteride is not approved by the FDA for use in women, and it's a category X drug, known to cause birth defects.
Propecia, the brand name for finasteride, is not prescribed for female patients due to its potential risks.
If your hair loss is determined to be female pattern baldness, your physician can recommend over-the-counter minoxidil or other prescribed medication.
Studies have been conducted on women, with one study observing 256 patients diagnosed with female pattern hair loss who took 5mg of finasteride.
For your interest: Were Not Here to Take Part?
Women who are pregnant or attempting to become pregnant should not take finasteride under any circumstances, as it's considered a Category X drug for pregnancy risk.
External genitalia abnormalities in a male fetus were reported in a study performed on animals, highlighting the serious risks associated with finasteride in pregnant women.
Treatment and Options
The most commonly used drugs for hair loss, alongside finasteride, are minoxidil (Rogaine) and finasteride (Propecia, Proscar). Minoxidil is a topical solution applied to the scalp to stimulate hair follicles.
Finasteride works by blocking an enzyme that converts testosterone into dihydrotestosterone (DHT), which causes hair follicles to shrink. It's generally accepted as the most effective non-surgical treatment for male pattern hair loss.
It's safe for most men to use finasteride, and most cases go without incident. However, it's recommended to check with an expert first, especially if you're not one of the men who tend to respond most impressively to finasteride.
Can Hair Loss Be Cured? Treatment Options
Hair loss can be a frustrating and distressing condition, but the good news is that it can be treated and even prevented in some cases. There are several treatment options available, and the most effective one for you will depend on the underlying cause of your hair loss.
Minoxidil, also known as Rogaine, is a topical solution that can be applied to the scalp to stimulate hair follicles. It's available in 2% and 5% solutions and is applied once daily.
Finasteride, on the other hand, is a pill that interferes with the production of a form of testosterone that contributes to baldness. It's not indicated for use in females, and women who are pregnant or may become pregnant should not handle crushed or broken finasteride tablets.
Hair growth has three stages: anagen, catagen, and telogen. During the anagen phase, hair grows, while during the catagen phase, it transitions to the telogen phase, where it rests before falling out. This process is a natural part of hair growth, but excessive hair loss can be a sign of a underlying condition.
An adult has about 100,000 to 150,000 hairs and loses up to 100 hairs a day. The scalp hair grows approximately 0.35 mm per day.
Dihydrotestosterone (DHT) is the main hormone responsible for androgenetic alopecia, also known as male or female pattern baldness. Finasteride belongs to type II '5-alpha-reductase inhibitors, which block the production of DHT.
Here are some key statistics about hair loss and finasteride:
- 86% of participants in clinical trials experienced a halt in hair loss progression
- 65% experienced a "substantial" increase in hair growth
- Finasteride is most effective in those with mild to moderate hair loss
- It's more effective in year five of use than in year one
It's essential to note that finasteride is not approved by the FDA for use in women, and women who are pregnant or may become pregnant should not take it. However, there are other medications available that can help with hair loss in women.
How to Take It
To take treatment for your condition, you'll need to follow the dosing instructions provided by your doctor.
You should take your medication at the same time every day to maintain consistent levels of the medication in your system.
The recommended dosage is usually 10-20 milligrams per day, but this may vary depending on your individual needs.
You may need to take your medication with food to prevent stomach upset, so be sure to follow your doctor's advice on this.
It's also essential to keep track of your medication schedule, so consider setting reminders or using a pill box to stay on track.
Warnings and Precautions
Finasteride should never be taken by women or children, as it can cause birth defects if a woman is exposed to it during pregnancy. This is a serious concern that should be taken into account by anyone who is considering taking the medication.
Before taking finasteride, it's essential to inform your doctor or pharmacist about any allergies you may have. This is crucial for ensuring your safety while taking the medication.
If you have liver disease or abnormal liver enzyme tests, finasteride may not be safe for you. This is because the medication can affect liver function, making it a potential concern for people with pre-existing liver issues.
Prostate cancer is another condition that may make finasteride a less desirable option. If you've been diagnosed with prostate cancer, you should discuss your treatment options with your doctor before taking finasteride.
Finasteride can also interact with other medical conditions, such as a bladder muscle disorder or stricture of the urethra. If you have either of these conditions, you should consult with your doctor before taking the medication.
Additionally, if you're unable to urinate or have had an allergic reaction to a similar medication called dutasteride (Avodart), you should be cautious about taking finasteride. These conditions can indicate a higher risk of adverse reactions to the medication.
Here are some conditions that may make finasteride a less safe option:
- liver disease, or abnormal liver enzyme tests;
- prostate cancer;
- a bladder muscle disorder;
- stricture of your urethra;
- if you are unable to urinate;
- if you have ever had an allergic reaction to a similar medicine called dutasteride (Avodart).
Frequently Asked Questions
Why do men not take finasteride?
Men may avoid taking finasteride due to potential side effects such as decreased libido, erectile dysfunction, and psychological depression. If you're considering finasteride, it's essential to weigh the benefits against these possible risks.
Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7308241/
- https://hairscience.org/news/are-finasteride-side-effects-permanent/
- https://www.esquire.com/uk/style/grooming/a33497206/finasteride-hair-loss-drug-does-it-work/
- https://www.hairphysician.com/finasteride-propecia/
- https://www.menspharmacy.co.uk/blog/finasteride/finasteride-are-the-risks-worth-it/
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