4 Primary Ways of Treating Hair Loss - Androgenic Alopecia (AGA)

  1. Using 5-AR (alpha-reductase) inhibitors “DHT blockers”
  2. Anagen Phase Stimulating Agents (anagen stimulants)
  3. Anti-androgenic agents (topical solutions) 
  4. Hair stem cell-related agents (injectable treatments)

Part 1

1. Inhibiting 5AR conversion from T to DHT ("DHT blocking")

DHT has been shown to progressively miniaturize the hair follicles on the scalp which is only one if its androgenic effects on human body.  Unfortunately this unfortunate effect of DHT only occurs by individual with genetic hair loss susceptibility.

Blocking DHT (dihydrotestosterone) always starts by inhibiting 5AR isoenzymes. Inhibiting the activity of type 1 and type II. 5 alpha reductase isoenzymes can be enough for the start. Men who suffer from any type of patterned hair loss (besides alopecia areata) start taking Finasteride (branded as Propecia, Proscar).

 Finasteride can inhhibit the 5-alpha reduction of Testosterone into DHT by approximately 70%. It is the only FDA approved oral drug for treating male pattern hair loss (AGA). 

Some Finasteride users may experience more than hair loss stabilization. Many of them also report positive hair thickening benefits over time. These are so called – well respondents to 5 AR inhibiting drugs.

Hair Follicle Androgen Receptor Sensitivity to Androgens and how Finasteride (Propecia) can help with hair loss


Inhibition of the 5 alpha reduction of Testosterone into several times more potent androgen – DHT results in less hair loss. Plasma DHT levels – lowered by Finasteride result in less frequent interaction of hair follicle´s androgen receptors with the DHT. 

For that reason, patients who use 5 AR inhibiting drugs like Finasteride tend to notice less hair loss. Importantly Finasteride limits the interaction of the most potent naturally-occurring androgen in your body DHT – with the hair follicles´ androgen receptor.

Types of 5 AR inhibitors effective for Hair Loss

Finasteride (Propecia,Proscar)
  • Inhibits 5-alpha reduction of T into DHT by 70% systemically and 50% topically
  • Only FDA approved oral medication for treating male pattern hair loss
  • Inhibits only type II. 5 AR isoenzyme activity
  • Requires prescription in most countries (excl. Turkey, Saudi Arabia)
  • Can come with potential side effects (statistically low percentage though)
Dutasteride (Avodart) 
  • 5-alpha reduction inhibition of T into DHT by 90-95% systemically 
  • Not FDA approved oral medication for treating male pattern hair loss
  • FDA approved medication for treating enlarged prostate in men
  • Suppresses type II. and type I. 5 AR isoenzymes activity 
  • Can come with potential side effects (statistically higher than Finasteride)
Topical Finasteride 0.25% Solution 
  • Suppression of 5-alpha reduction of T into DHT by 70% topically (study)
  • Very low (if any) effect on systemic DHT suppression
  • Not FDA approved oral medication for treating male pattern hair loss
  • Inhibits only type II. 5 AR isoenzyme activity
  • Can be compounded by a licensed pharmacy or bought online for research purposes
  • Requires a prescription sometimes by purchases from a pharmacy
  • Side effects can´t be entirely avoided either (statistically lower as opposed to oral Finasteride)
Topical Dutasteride
  • Very few clinical studies done on topical Dutasteride
  • Better efficacy as opposed to topical Finasteride can be expected but only via transdermal injection delivery or mesotherapy 
  • Low potential for systemic DHT suppression
  • Higher mollecular weight compared to topical finasteride restricting proper transdermal absorption
  • Not FDA approved for treating male pattern hair loss
  • Topical dutasteride application via mesotherapy is still relatively unknown among dermatologists and hair transplant doctors
Saw Palmetto (Serenoa repens)
  • Inhibits 5-alpha reduction of T into DHT by 32% systemically
  • Not FDA approved oral medication for treating male pattern hair loss
  • Less potent 5 AR inhibitor in comparison to Finasteride or Dutasteride
  • Side effects haven´t been observed but can occur

The pros and cons of using 5 AR inhibiting agents for long-term hair loss management (AGA)


Finasteride has been the most studied and most researched 5 AR inhibitor ever approved for hair loss by the FDA.

5 AR inhibitors tend to work well for majority of guys initially. However after some time their effectiveness may start to fade. How soon, will depend on the severity/aggressiveness of your AGA and changes in your androgen levels as you age.

Use of 5 AR inhibitors has been shown not only to slow down male pattern hair loss progression but also result in thicker scalp hair growth. Hair thickening effect after using 5 AR inhibitor depends on how good of a respondent you are. 


5 AR inhibitors may not be enough for men with more “severe” genetic hair loss condition. 

5 AR inhibitors don´t protect the hair follicles´ androgen receptors from androgens in general.

DHT leftovers, testosterone and other “weaker” androgens can still cause hair loss by individuals with genetic hair loss condition using Finasteride already.

5 AR inhibitors are not able to “block” the androgenic effects of natural androgens or steroidal androgens.

Potential side effects related to low sexual desire, low libido, decreased sexual arousal , weak erections by small percentage of users were observed by 5 AR inhibitor users. Statistically only 1-2% of men experience side effects from drugs like Finasteride (slightly higher side effect profile by Dutasteride).

Make sure you do your due diligence on PFS (post finasteride syndrome)– mixture of psychologically- and sexually-related side effects, depression, suicidal thoughts, anxiety.

PFS suggests that these side effects may also persist after patients discontinue the use of any 5 AR inhibiting agent like Finasteride or Dutasteride.

Why are 5 AR inhibitors effective for the start?


DHT is the most potent androgen causing hair loss. DHT does it to the highest degree in comparison to other androgens like testosterone. Especially because it has a much higher binding affinity onto the androgen receptor of the hair follicle. By focusing on 5 AR inhibition and thus DHT suppression, most of men start seeing clear improvements. Less hair loss, hair becomes thicker and better to style again.

DHT is more likely to transcribe its potential damaging effects onto the hair follicle than any naturally-occurring androgen.  By inhibiting it 70% with Finasteride or  90%+ with Dutasteride, the pressure can be put off the androgen receptor. It only works while 5 AR is being inhibited. 

The efficacy of 5 AR inhibiting medication depends on the frequency and dosage of the used drug. 

Biological half-life of 5 AR inhibitors (Finasteride vs. Dutasteride)

Finasterides´ elimination half-life is only 6-8 hours whereas Dutasteride has a much longer half-life – up to 6 weeks. Consult a hair transplant doctor, dermatologist or any licensed medical professional to find out the optimal dosage for you.

How well the 5 AR inhibitors will work for you, depends on how good of a respondent you are. Many guys keep using Finasteride for a successful long term hair loss management for many years. Meanwhile 1 or more hair transplants may be required for improved hair density and thickness. 

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