Propecia (Finasteride)

Finasteride (brand-name Propecia) is a daily oral medication that helps to slow down and somewhat reverse male-pattern baldness.The progression of hair loss is expressed in two ways: first, shortening of the hair-growth cycle, and second, diminishing of the hair-shaft size/diameter. In other words, hair loss is seen as a process of hairs shrinking from healthy terminal hairs that progressively miniaturize to fine, vellus hairs.The mechanism by which finasteride works is through blocking the conversion of testosterone to dihydrotestosterone (DHT) via an enzyme 5-alpha-reductase Type 2. With less DHT present, fewer hairs are susceptible to the hair-loss process; some hairs are growing again; and some hairs are growing thicker.Propecia takes several months of usage before visible signs of hair growth are present.

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Key Points

  • An ideal candidate
    • A male experiencing hair suddenly shedding or slowly diminishing in volume over time(miniaturization)
    • A male who would like hair-transplant surgery but would also like to slow down his current hair loss with medical therapy

  • What to do
    • This is a prescription-only medication and Dr. Lam can write your initial prescription for you. You must sign a consent form that describes the risks, benefits, and limitations of finasteride before receiving the prescription.
    • If you received a prescription from us, please keep in mind that after one year, when your prescription is due for renewal, you will have to see your family doctor. The reason for this request is that Dr. Lam does not check on your laboratory blood work and since the medication is cleared through both your kidneys and liver (as almost all medications do), it is worth to ensure that your blood levels remain normal.
  • What to expect
    • The change in hair appearance may show as early as 4 to 6 months and should continue to improve over the ensuing months. Your hair should slow down in shedding and you could see an improvement in hair count and hair volume. We will follow up with you to take photos and monitor your progress
    • In preparation for hair transplant, the strengthening of the hair is experienced as early as 4-6 weeks, which may decrease the extent of postoperative shock loss but not completely prevent it. Of note, you may notice some temporary increased shedding 4 to 8 weeks after starting finasteride since some of the hairs maybe being pushed into a growth, or anagen, phase. This shedding does not always occur though.


  • Does it work in every patient?
    Finasteride is highly effective and works in 99% of men who take it. Some patients have decided that it did not work for them and usually the reason for this is that they just failed to notice the difference (that is why we have standardized photography) or continued to lose more hair despite the benefits of finasteride. Although finasteride can slow down hair-loss progression and improve hair growth, in younger men with rapid hair lossthere still could be ongoing hair-loss progression.
  • Do I need minoxidil or other medical therapies if I am on finasteride?
    In short, yes, if possible. Minoxidil works synergistically (or additively) with finasteride. Someone who has been on finasteride for a long time then adds minoxidil should see an uptick in improvement. Conversely, someone who has been on both finasteride and minoxidiland who stops one or the other product will notice similar worsening. As many therapies (finasteride, minoxidil, laser, and PRP injections) that one can afford, can tolerate, and desires because all of these methods are additive in their benefits. Finasteride offers the strongest benefit for the patient but all therapies are very helpful when used in combination. Dr. Lam will help consult with you on the pros and cons of all the medications to help you decide which combination of medications may be ideal for you.
  • Tell me about the side-effect.
    The most common side-effect for finasteride is sexual side effect, typically a reduction in libido that could in some patients lead to erectile dysfunction. In rarer cases, there can be breast tenderness or change in mood, especially if someone has already been on anti-depressants. The initial studies have shown an incidence of less than 1% compared with placebo for sexual side effects but some uncontrolled post-marketing surveys have raised the alarm of permanent sexual side effects in a small group of men. Although there have been scattered reports, there have been no large-scale clinical reports about this trend, and Dr. Lam finds that this medication is not only highly effective but very safe as well. There has also been a documented incidence of what is called a nocebo effect, i.e., simply counseling someone about the potential for a side effect can lead to the occurrenceof the side effect.
  • If I experience side effects, what can I do?
    In initial Merck studies, they found that 57% of men who continued medications for a month or more had complete resolution of any of their side effects. Accordingly, it may be worth continuing the medication for a minimum of one month before coming to a conclusion about whether you should continue or not. Another option if side effects do arise is to consider taking one pill every other day rather than daily. In Dr. Lam’s experience, doing so has taken care of the majority of issues in those who experience them. The effectiveness of finasteride maybe somewhat reduced but it is still worth taking it at this reduced dosage.
  • What if I stop taking the medication?
    Unfortunately, all of the hair that is preserved during the time you are on finasteride will be lost over 4 to 6 months when the medication is stopped. To clarify, if you have been on the medication for 5 years and then stop, the amount of hair that was preserved during that time will be lost (not more hair than you would have lost). This can be very discouraging to hear but with such an effective medication available, Dr. Lam likes to help your psychology by saying: “Keep taking finasteride for as long as you care that you have hair or until a better medication comes around.” Of note, there are so many technological breakthroughs that are on their way like prostaglandin modulators (both topical and oral), DNA 3D printing of follicles, etc. However, if you don’t start taking finasteride and wait until these medications arrive on the market you may have irreversibly lost so much hair than finasteride or another medication will be less effective. Accordingly, you should start your medication as soon as you can and be as compliant as you can.
  • What are your thoughts on generic versus brand name?
    If there is a choice, Dr. Lam recommends the brand name. He believes that he has seen a higher efficacy and lower side-effect profile with brand name Propecia. (Dr. Lam does not own stock in Merck or have any financial affiliation with the company.) However, many men decide to use the generic finasteride 1 mg that is now available. In the past (and even until this day), many men take a 5-mg finasteride generic and cut it into 4 pills, taking a fourth of a pill a day (which is approximately 1.25 mg per day). Besides the inconvenience, it is important to note that crushed pills with powder residue should not be handled by a woman who can get pregnant since it can lead to a birth abnormality in a male fetus’ genitalia. No birth defects should occur if a man takes it though and gets a woman pregnant.
  • What does dutasteride (Avodart) do compared with finasteride (Propecia)?
    Dutasteride (Avodart) is a dual alpha-reductase inhibitor blocking both alpha-reductase type 1 and alpha-reductase type 2. Finasteride (Propecia) only blocks type 2. Accordingly, finasteride only blocks about 65% of circulating DHT; whereas dutasteride can block up to 99% of circulating DHT. Theoretically,dutasteride can be even more powerful in cases of male-pattern baldness but it is not FDA-approved for hair loss. Avodart is typically marketed for men with enlarged prostates (benign prostatic hyperplasia) to help with urination. Dr. Lam in general does not know about the long-term effects of taking Avodart, so he does not prescribe this medication for hair loss.
  • Can I take a higher dosage?
    You do not need a higher dose of finasteride above 1 mg. Studies have compared 1 mg versus 5 mg dosage and found the efficacy in male-pattern baldness to be the same. Increasing the dosage only raises the potential side-effect profile without additional improvement in hair growth.
  • What if I am taking Proscar already?
    If you are taking Proscar (which is a 5-mg form of finasteride) for prostate BPH condition, then you don’t need to take Propecia since that would be overkill. The 5 mg Proscar will provide the coverage you need for the hair as well.
  • Does it work for women too?
    Earlier studies have found no benefit in postmenopausal women. Some more recent studies have shown that finasteride may help postmenopausal women who experience hair loss. It is somewhat unclear as to how beneficial finasteride is in women. One thing is clear is that it is absolutely prohibited in women of childbearing age because it can lead to birth defects in children for women who take finasteride during their pregnancy. As a general rule, Dr. Lam does not prescribe finasteride for women.
  • I heard that finasteride only works well in the crown region but not in the front of the scalp like the hairline?
    This is false. The reason why the package insert only states the efficacy in the crown is that initial FDA trials only evaluated the crown, so the package insert has to reflect the parameters of those clinical trials. Nevertheless, subsequent to those trials, studies have shown that finasteride works very well in the front and the back of the scalp.


Medical Therapy for Hair Loss Lecture at the 7th Annual Hair Transplant 360 Workshop
Testosterone Therapy and Male Hair Loss Thoughts & Ideas by Dr. Sam Lam
New Proposal of Finasteride (Propecia) Mechanism of Action


View more Propecia (Finasteride) Before & After photos.

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