This is a bit of a hard one to crack, on the one hand yes and there are a few factors that are quite well proven, on the other hand there’s limited evidence for a lot of the claims you’ll hear around beard growth oils.
To start with, beard hygiene like any hair covered area does in fact effect growth, conditioning will affect thickness and there’s reasonable evidence that certain essential oils can increase blood flow to the area, reduce harmful bacterial build up and of course condition the beard. Once we start getting to the hormone related claims things get a bit sketchier.
If you get something that uses high quality oils, it’s definitely going to improve the look of your beard in the same way that you’d expect a good conditioner to improve your hair. And yes, we will get to a recommendation later, and no big surprise, it’s not one of the $10 options as there’s generally a lot more chemicals and less of the good stuff in these cheap options which are ultimately better for styling rather than looking after your facial fuzz. The good news here is that a bottle of decent beard oil can be used pretty sparingly meaning that you’ll only go through about 2 or 3 a year even if you’ve got a longer beard, so it’s not actually more expensive as a little goes a long way with the better quality products.
So, if the question is do beard oils work? Then yes, but there are a lot of myths about them too.
The Quick Recommendation If You’re Looking
Generally, we recommend mengineoil.com and for 3 core reasons, first up, they only use high end oils in what is theoretically their most effective dosages. Second, they have a money back satisfaction guarantee, which we had one of our mystery shoppers check. And lastly, they were the only company to provide us with 3rd party testing certificates when we asked them to prove that they contained exactly what they said they did. Remember, this market is pretty unregulated so people can put the lowest quality oils in that are mostly water and just say they use the good stuff.
Explaining the breakdown of beard oils
Beard oils are normally made of base oils and essential oils. Base oils are what make up about 90% of oils because the essential oils will irritate the skin in too high of a dose. 
Essential oils are those that have other functions. Now, essential oils do have a lot of “woo woo” associated with them, but there’s some science here too for some of them at least. Mint oil containing menthol for example, which can stimulate blood flow to the hair follicles. Think the same way it can unblock your nose when you have the flu it’s working by increasing the blood flow in the area. 
It's also worth noting men’s skin is less sensitive than women’s and men also have different follicle sizes, ultimately meaning they need a higher dose than would be in a women’s scalp oil for example. 
You do also sometimes get some other ingredients like caffeine etc, but we’ll come back to that later.
So, What Beard Growth Oil Claims Hold Up
Now, that we’ve covered the core makeup well explain a bit more about how they can work.
Conditioning for Thickness
If your beard hair is well conditioned, it will be thicker, it will look fuller, rather than actually being fuller but how it looks is ultimately what we care about here. Argan is the best base oil for this, but if you have a 80% plus argan, which if there’s no other base oil (see mengineoil that we recommended before for example) you will need to use it sparingly or it can be a bit heavy on the beard. Jojoba is generally the lighter, less effective, cheaper version, but it’s generally a good second choice. Coconut is probably third and a lot of the other oils are just cheap alternatives, that don’t work nearly as well. 
Cleaning the skin and follicles
One of the things that slows hair growth is bacteria or muck building up in the follicles, certain oils can help deal with this, peppermint as we mentioned, or lavender are two common choices for this due to them having anti bacterial qualities. Pretty straightforward, this also can help for avoiding ingrown hairs too.
Menthol as we mentioned when we were first explaining what an essential oil is, and that they’re not complete mumbo jumbo, can improve circulation. Improving circulation can improve hair growth, this is also where the idea for things like skin needling comes from. Now, it’s not going to work for everyone, it’s about a 30% strike rate by the studies, but it’s a viable factor. [2,5]
Rosemary Oil and DHT
This one’s a little early in the research, and whilst rosemary oil has been trialled against minoxidil and has shown to be as effective (in 2 trials, not enough to say for sure), it hasn’t been tested on beards though, only on scalps. 
The Myths Around Beard Oil
Lack of Scientific Evidence
No topical product can change the genetic factors that determine the growth rate and thickness of facial hair.
The growth of facial hair is primarily influenced by genetics and hormones. Oils can assist the growth, but if you’re really not genetically disposed to it, then it’s not going to make all of the difference.
Marketing Gimmicks and Exaggerated Claims
Many manufacturers of beard growth oils use clever marketing tactics to create the illusion of effectiveness. They often use terms like "active ingredients," "stimulating serum," and "proven results" to make their products appear more legitimate. However, upon closer inspection, it becomes evident that these claims are exaggerated and not supported by scientific research.
The Role of Genetics and Hormones
The growth of facial hair is largely determined by genetics and hormones. Each individual has a predetermined number of hair follicles on their face, and these follicles dictate the maximum potential for beard growth. Testosterone a hormone responsible for the development of male characteristics plays a role in beard growth as well. This of course has to be factored in.
Choosing the Right Beard Oil
When selecting a beard oil for hair growth it is important to pay attention to the ingredients and opt for products that are free from toxic additives like parabens, sulfates, mineral oils, and silicones. Look for beard oils that contain high quality carrier oils and essential oils known for their moisturizing and nourishing properties.
While these oils may not directly promote beard growth in a magic bullet kind of way. They do however contribute to the overall health (which effects growth) thickness and appearance of the beard.
To Wrap Up
So, whilst beard growth oils are not a magical solution for achieving a thick and full beard. They can play a decent role in your overall beard care, which is essential for optimal growth.
And although the growth of facial hair is primarily determined by genetic factors and hormones proper beard care, including regular cleansing, moisturizing, and grooming, is essential for achieving optimal beard growth. But, you’re unlikely to take peach fuzz to an honest Abe with a bit of beard oil.
1 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6348851/
2 - thttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406845/
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6116811/
4 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5535876/
5 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10160692/
6 - https://pubmed.ncbi.nlm.nih.gov/25842469/