Finasteride, sold as Propecia and Proscar, is an antiandrogen that decreases dihydrotestosterone (DHT). It’s used to treat hair loss and benign prostatic hyperplasia (BPH, also called an enlarged prostate) in men. Overall, side effects are rare, although men at risk for prostate cancer or living with erectile dysfunction should discuss using finasteride with their doctor.
What Does Finasteride Do to the Body?
Finasteride reduces the amount of dihydrotestosterone, or DHT, in your body. Medically speaking, it inhibits the action of the enzyme 5α-reductase, which converts testosterone to DHT.
Once you’re past puberty, DHT’s job in the body is largely to maintain the seminal vesicles, prostate, and male sexual function. When DHT is out of whack, you get benign prostatic hyperplasia, or BPH. The prostate compresses the urinary tract from both sides, making it more difficult to start or stop urinating and making it hard to empty the bladder.
Finasteride in a 5 milligram daily dose can help balance DHT levels for men with enlarged prostates to help them go to the bathroom more easily.
DHT, like other androgens, can also affect hair. Hair follicles have a natural cycle where they regrow from a root before entering a resting phase. The follicle falls out, and a new root grows. Androgens can inhibit this cycle and interfere with the growth of the root, leading to thinner and more brittle hair. The medical name for this is androgenic alopecia.
Thus, reducing the amount of DHT in your body with a 1 milligram daily dose of finasteride makes it easier on your follicles. It causes hair to grow fuller and stronger and allows the natural hair cycle to continue.
Do I Need A Prescription for Finasteride?
Yes, but generally speaking, you can get a prescription for finasteride with a telehealth consult (including here at eDrugstore). Finasteride is viewed as “generally considered safe,” with major side effects being rare and none that are medically dangerous.
What are Finasteride’s Contraindications?
As of this writing, there are no drugs identified that might interact with the body in finasteride, and if you enjoy grapefruit for breakfast or a drink with dinner, that’s also shown no impact. That said, if you have a hormone disorder or believe you might have one, you should get tested before using finasteride to avoid any possible complications.
There is some evidence that herbal supplements like St. John’s wort may reduce the efficacy of finasteride, but research into this topic is ongoing. As a general rule, if you’re taking prescription medication, it’s best to avoid herbal supplements to limit possible interactions.
Does Finasteride Have Side Effects? How Common are They?
The most commonly reported symptoms include:
- Cold sweats
- Dizziness, faintness, or lightheadedness when standing from a seated position or lying down
Possible sexual side effects include:
- Decreased interest in sex
- Inability to have or keep an erection
- Loss in sexual ability, desire, drive, or performance
Overall reporting of sexual side effects indicates between 3% and 10% of those who use finasteride may experience these side effects to some degree.
Less common side effects include bloating, gynecomastia (growth of the breast tissue), skin irritation, weight gain, swelling in the facial area, pain or discharge from the nipples, tingling in the extremities, back pain, flu-and-cold-like symptoms, and decreased semen volume.
If you experience any of these side effects, contact a doctor immediately.
Can Finasteride Cause Erectile Dysfunction?
The connection between 5α-reductase inhibitors and ED is a complicated one. Everyone’s body is different, and every case of ED is unique to that person. So, for example, a case of ED that’s primarily a cardiovascular or psychological issue is unlikely to be as affected by taking finasteride, while a hormonal cause might be a different matter.
Can I Overdose on Finasteride?
While taking more of the recommended dose of any medication is not recommended, clinical tests have not found a dangerous dose. If you accidentally take more than one dose, simply wait for 24 to 48 hours before taking another one.
Can Women Take Finasteride?
There is a recommended use for women, for the management of hirsutism (excessive hair growth). That said, it’s rarely prescribed in that fashion. In some countries, it’s not recommend for women at all.
Which Is Better for BPH, Finasteride or Tadalafil?
Doctors may be slightly hesitant to use tadalafil this way because they don’t know precisely why it helps reduce the size of the prostate. Tadalafil works by inhibiting the enzyme PDE-5, and that prevents the dilation of blood vessels. Other drugs also do this, but so far, none seem to have any impact on BPH. Part of “first do no harm” for doctors is to understand what they’re asking a patient to put in their body. For that reason alone, doctors often see finasteride as the better choice.
In the absence of ED and considering the relatively low likelihood of sexual side effects, doctors who skew towards the more conservative end of the medical spectrum are likely to go with finasteride first. If the patient starts reporting sexual side effects, then they’ll switch to tadalafil/Cialis.
Another disadvantage of tadalafil is that it has more contraindications. Heart disease and hypertension patients generally shouldn’t take tadalafil, and it can’t be taken with alpha blockers. Finasteride, by contrast, doesn’t seem to have any negative interactions with other medication and is often prescribed to help relieve BPH in men who also take alpha blockers.
That said, finasteride may not be the best option for patients with prostate cancer or its risk factors. If you have a history of prostate cancer in the family, you might be better off with Cialis.
And some men don’t have to choose. Pairing finasteride and tadalafil together is showing promising results in studies, where the two work well together.
eDrugstore Has Your Back
To learn more about finasteride and hair restoration, follow our blog. To talk to one of our U.S.-licensed physicians and get a prescription for finasteride, call 1-800-467-5146. Your medication will be shipped at no charge right to your door.
To learn about the erectile dysfunction medications we carry, see our medication guide or call for a consultation. Virtual health visits and shipping are always free.
Dan is a long-time freelance writer focusing on technology, science, health, and medicine, with a lifelong interest in physics, biology, and medicine. His work has taken a particular focus on scientific studies “beyond the headlines,” reading the study to more closely examine the results.