DHT is an androgen hormone and can be directly associated with facial hair. Along with testosterone, which dihydrotestosterone is synthesized from with the help of 5-alpha reductase, these two androgens are the most important hormones that a beard forms from 1)2)3)
Without DHT, there is no beard. Some bearded men feel that this is incorrect despite scientific evidence and opt to use DHT blockers because “DHT is responsible for hair loss.” What they don't realize is that in spite of using DHT blocking ingredients, such as some essential oils, the reason these men see beard growth is because DHT is not being hindered — at least not to any substantial extent. Even if a bearded man feels he is progressing with his facial hair while using a DHT blocker, it could potentially mean he would see even better progress without it.
Topical DHT blockers are not nearly as potent as oral (prescription) blockers and pose less risk of some beard hair thinning. Because there is still risk, however, it is always advised to stay away from potential DHT blockers.
A DHT blocker is something that inhibits the production of dihydrotestosterone by limiting 5-alpha reductase's (5AR) ability to convert testosterone to DHT. Topical DHT blockers that you apply directly to your skin, such as some essential oils, are not as effective as oral solutions like finasteride and dutasteride.
If you want the best beard growth possible, stay away from DHT-inhibiting oils and foods. Men that naturally have high androgen sensitivity likely will not need to worry as much as those that have more of a struggle to grow a beard, but it is still recommended that all men stay away from DHT blockers.
There is no way, at this moment, to know how much a potential DHT blocker affects one person to the next. Keep in mind that individuals vary, and simply seeing that something works, or does not, for one person, means little to the next. It is much easier to use a catch-all and call DHT blockers bad for facial hair. Because if they work as intended for an individual, they are.
Sam at Beardology.org has compiled a list of known DHT blockers4). These comprise of products containing high quantities of lauric, oleic and linoleic acid which are three fatty acids which have been proven through scientific studies to inhibit the production of DHT.
Some also contain other components that allow them to inhibit DHT production in a different way. For example, Coconut oil inhibits DHT topically because of it’s lauric acid content, but it also inhibits DHT when ingested because of it’s beta sitosterol content.
Keep in mind that this is not a complete list so just because something does not appear on here does not necessarily mean it does not inhibit DHT.
DHT INHIBITORS: