Does testosterone cause Hair loss?
THE SHORT ANSWER:
No, hair loss aka. androgenic alopecia, is mostly genetic. For the most part, testosterone replacement therapy will not cause hair loss. This is somewhat of a complicated issue, so continue reading if you would like to know the details. Information regarding hair loss treatments and my thoughts on the best hair growth products are at the bottom of the article.
Testosterone and dht
When testosterone is produced it can either act on cells itself, or it can be converted into other hormones. In a man’s body testosterone is mainly converted into estrogen or DHT. Both of these hormones are very important for normal body functions. Some cells have an enzyme called 5-alpha-reductase (5-AR),which convert testosterone into DHT. There are basically two versions of this enzyme called 5-alpha-reductase 1 and 2 (this will be important later, when I discuss medications for hair loss).
Type 1 is found on sebaceous (oil producing) glands, sweat glands and the scalp. Type 2 is specific to hair follicles and the prostate. When it comes to hair loss it is the Type 2 5-alpha reductase that is most important.
Dht and its relationship to hair loss
There continues to be lots of controversy in this area, but for the most part research indicates that DHT is the most important hormone when it comes to alopecia. Some hair follicles are genetically, more sensitive to DHT than other follicles (1). You may notice that most bald men have a particular pattern to their hair loss. Typically hair towards the front and top of the scalp are more sensitive to DHT, than hair follicles at the sides. Those follicles for some reason are more genetically sensitive to the attachment of DHT to their receptor. Interestingly, genetics do not seem to completely explain male pattern baldness. Some studies have shown that in sets of identical twins, one twin may bald faster than the other (2). This may be explained by something called epigenetics, which has to do with how some genes are expressed.
how much dht causes hair loss?
As stated previously, testosterone converts to DHT. So you may be thinking, if I increase my testosterone, won’t my DHT levels increase? The answer is yes. The next question is: If DHT is related to hair loss, then won’t increased DHT cause increased hair loss? Luckily some researchers answered this exact question. In this study, researchers compared levels of DHT in individuals with hair loss and compared them with people without hair loss. They found that DHT levels were similar in both groups. The researchers concluded that, “increased serum concentrations of DHT were not correlated with the advance of alopecia.” They went on to say, “Based on the results of our study and others, the most important factors would appear to be the genetically-determined sensitivity of the follicles to DHT and their different reactions to androgen concentration.”
So research seems to indicate that by increasing our DHT levels, by increasing testosterone levels should not cause an increase in hair loss. This makes sense especially when we think about what is going on at the level of the hair follicle. The hair follicle itself contains the enzyme (5-alpha-reductase), that is responsible for converting testosterone to DHT. Research has shown that even individuals with very low levels of testosterone (250 ng/dL), have enough testosterone to saturate the DHT receptors on the hair follicles. So, it takes very little testosterone to cause hair loss. Increasing testosterone levels to the high end of normal, will not cause any further increase the the saturation of the hair follicle with DHT. (insert study)
hair loss treatments – medications
This is also a complicated area. I have attempted to distill the research down to the best treatments for hair loss or thinning hair. The point that I also want to get across is that any time we put a medication in our body, there are other effects aside from the desired effect we want. Patients need to understand this, and make an informed decision before they decide to use a medication. Too often the adverse effects are not understood or reviewed before a medication is started. It makes sense to think of each medication in terms of not only its benefit, but also the unintended side effects.
This is not a complete list, but rather a review of the most proven methods to help slow or stop hair loss. There are essentially two categories of medications DHT blockers and medications that stimulate hair growth. I also review newer medications that show some promise.
1. Oral Finasteride (Propecia) –
The Good: Finasteride works by inhibiting the enzyme 5-alpha reductase type 2 (i.e. specific to hair follicles). As a results Finasteride has been shown to decrease hair loss, increase hair growth and improve hair quality (3). Most guys who take it, will tell you that’s exactly what they experience. Finasteride has a short half-life (5-6 hrs), which means it needs to be taken daily, but overall it seems to be very effective.
Added Bonus: In addition to the effects on hair, a large study showed a 25% reduction in prostate cancer in men who took finasteride. The researchers also noted that there did not appear to be an increase in high grade prostate cancer or deaths (4).
The Bad: Over the past few years there has been growing concern regarding the side effects. It has even been given the name “Post-Finasteride Syndrome”. Finasteride is very effective in lowering DHT levels, by about 70% (5). There are reports of decreased sex drive, erectile dysfunction, decreased ejaculate volume and difficulty achieving orgasm. The incidence of side effects varies by the study, but the incidence is thought to be about 4-6% of men (6). Thankfully, these side effects are not permanent and should improve within a few months after stopping the medication. I believe that DHT levels should always be measured before a patient begins using this mediation.
The Unknown – Aside from the rare sexual issues, what are the long term effects of lowering DHT? Nobody really knows. It is thought to be safe, but we were also told Zantac was safe. Metabolites of DHT have found to be active neurohormones (hormones that work on nerve tissue). There have been reports of increased depression in men taking finasteride. I believe there are better hair loss solutions available:
2. Topical Finasteride –
The Good: If taking a finasteride pill decreases DHT significantly, then possibly applying finasteride on the scalp will target the medication where we want it and we can avoid side effects. The answer to this seems to be yes…topical finasteride appears to work just as well as oral finasteride according to studies. The next question is: Can topical finasteride be absorbed into the blood stream and cause the same problems as the oral form? Answer below:
The Bad: There appears to be conflicting data regarding systemic absorption of finasteride. This study, showed that a 0.25% solution of topical finasteride lowered serum DHT by 69-75%, similar to the oral form of the medication. However, this study showed a 24-48% reduction in serum DHT, depending upon the dose used. My opinion is that the topical form probably absorbs at different rates in different individuals. The topical finasteride likely has the similar side effect profile as oral finasteride, but likely to a lesser degree. If you have a history of low libido and/or erectile dysfunction, it is probably best to avoid using finasteride (at least until it improves), there are better alternatives. Also testing your DHT levels before starting the medication is probably a good idea.
3. Dutasteride (avodart) –
The Good: Dutasteride is a cousin of finasteride. It inhibits both type 1 and type 2, 5-alpha-reductase and appears to be a stronger medication with a longer half-life (lasts longer in the body). Because it is stronger dutasteride will lower serum DHT even more so than finasteride, with some research showing as much as 90% suppression of serum DHT. As a result dutasteride will be more effective at treating hair loss when compared to finasteride.
The Bad: Since dutasteride is overall stronger than finasteride, we can expect a higher side effect profile. This has not panned out in the research, but it continues to be studied. In addition, the half-life (time it takes for half the medication to be eliminated) for dutasteride is a very long 5 weeks. That means after 5 weeks only half of the medication has been eliminated. So if side effects occur, it could take a very long time for you to improve. Some physicians compensate for the strength of dutasteride by having patients take the lowest dose of the medication every other day. This reasoning seems to be sound. My opinion is that if you have a history of low libido and/or other sexual problems to avoid taking dutasteride orally. However, there may be an alternative, which is topical dutasteride.
4. Topical Dutasteride –
The Good: Given what we already know about topical finasteride and the effectiveness or oral dutasteride, the topical version should be very effective for hair loss. It should be at least, if not more, effective as topical finasteride. There also may be some other advantages. The absorption into the blood stream for dutasteride should be much less, since dutasteride is a larger molecule and will have a harder time being absorbed into the blood stream. This would make systemic absorption less likely. In addition, dutasteride is more lipophilic (fat loving), which should allow it to remain on the skin longer leading to less systemic absorption.
The Bad: There is not much research regarding topical dutasteride at this point. However, given everything we know it is a very promising alternative for hair loss.
5. Topical Minoxidil (Rogaine) –
The Good: Minoxidil has been around a long time. It was first researched as a blood pressure lowering medication, since it relaxes blood vessels and improves blood flow. Researchers noticed that not only did blood pressure improve, but subjects also saw an improvement in hair loss. Minoxidil works by a different mechanism compared to the medications we have already discussed and is applied topically to the scalp. It is not exactly understood how minioxidil works, but researchers think that it reverses the miniaturization of hair follicles and increases blood flow to the follicles.
The Bad: Minoxidil has a lot of research behind it, and is thought to be very safe. It does have to be applied twice per day and if it is discontinued hair loss will resume quickly. It is important that it be applied as directed and you should make every effort not to miss applications.
Can these medications be combined for better effects?
The answer is yes and they do seem to work better together. This study looked at the combined effects of topical minoxidil and finasteride, compared to minoxidil alone. They concluded: “Treatment with topical solution of 0.25% finasteride admixed with 3% minoxidil was significantly superior to 3% minoxidil solution for promoting hair growth in male androgenetic alopecia, and well tolerated.”
This makes sense, as blocking the DHT at the follicle and increasing the blood supply to the follicle, attack the problem from different angles and should provide superior results, compared to either one alone.
Topical dustasteride & minoxidil
As you might have guessed, the ultimate combination for hair loss is likely a combination of minoxidil and dutasteride. This combination is not currently approved by the FDA for the treatment of hair loss. Therefore it is not available at a regular pharmacy like Walgreens. The only way to obtain this combination would be through a compounding pharmacy. This is can be obtained from a physician or PA or is comfortable prescribing it.