The internet lives in mysticism and myth — especially when it comes to adding magical mojo to your guitars — but there’s one bit of medicinal shamanism for any non-sealed guitar fingerboard that you should know about right now; and that well-kept secret is a special bore oil formulation called “Fret Doctor.”

I am a wild and obsessive supporter of this miracle oil when it comes to preserving and bringing out the real personality of a rosewood or ebony fretboard.

Here is some background on the history of Fret Doctor:

Guitar players are sometimes troubled with the problem of micro cracking of their fretboards, which can lead to other problems. Guitar fretboards and inlays are often made from the very same hardwoods that are used in woodwinds like the fife: Rosewood, Grenadilla or Blackwood, Boxwood, Cocobolo, and Ebony, just to name a few. Like woodwinds, fretboards are sensitive to the problem of dimensional instability.

The fret beds expand as the wood shrinks, stressing the adhesive holding the frets of the instrument, often developing the problem guitarists call “buzz.” The wood shrinks on the short axis, causing what is commonly referred to as “fret sprout.” The fret isn’t growing… the wood is shrinking!

The best way to prevent these problems is to maintain the moisture level in the wood at where it was when the instrument was constructed. Just like with woodwinds, mineral oil, silicones, and various other substances don’t really penetrate the wood. The wood remains dry inside.

I have a lot of guitars, and when I decided to make the Fret Doctor leap, I was amazed to learn how well the bore oil worked on all my rosewood fingerboards.  The rosewood color deepened and richened and the wood became fuller and smoother.  It was as if I had a whole new guitar!  Who knew my fretboards were dying of thirst?

Here’s how Bore Oil looks and works on a rosewood fingerboard:

I put the bore oil on my fingerboards and let it sit for an hour and then I wiped it off.  There’s no danger in over-saturating the wood.  The fingerboards take in as much bore oil as they need and then they stop drinking.  It’s a perfect event to watch because, fret section by fret section on the same guitar, the need for the oil varies by quite a bit.

Fret Doctor makes the most obvious and lasting effect on rosewood fingerboards.  On my ebony boards, I could see they were thirsty and lapping up the oil, but the color didn’t change much, and the consistency of wood did not harden, but it’s good to know many of those dark boards are now quenched, too.

Fret Doctor doesn’t work on maple fretboards since they are usually sealed with urethane or some other lacquer or varnish product, so sorry, Messrs. Johnson, Gilmour, Clapton and Smith! Fret Doctor works best on natural, unsealed, wood.

I had no idea I would be so thoroughly convinced that Fret Doctor is worth every cent.  You see the benefit, and the magnificent difference, the second the first drop of the bore oil lands on your fingerboard; and I confess to having a slight bit of guilt for waiting so long to do the right thing by my fingerboard friends who play so thoroughly with me every single day.


I dropped Ed Boyle — the real doctor in “Fret Doctor” — a line to tell him how much I love and appreciate his special oil, and Ed was kind enough to reply with even more detail, and I have his permission to share the information with you, with a couple of small redactions to preserve anonymity:

Thank you, David:

The Internet is truly amazing. In about 11 years, with absolutely no advertising, FretDoctor is now in use all around the world, promoted by very happy users. I thank you for your mention on your blog. This product is very expensive to make and has no real advertising budget, nor does it need one. About 40% of my orders are international in nature. In that time, I have had but 1 complaint. That was from a musician who had such a thick coat of Linseed oil on his board that a bullet could not penetrate it.

I have seen the product solve many difficult problems. For example: A man from [redacted] contacted me, telling me that he wanted to “polish ” his frets. He consulted a friend, who told him to use Brasso, an abrasive polishing compound, loaded with fine particulate matter. He applied it and got it all over the fretboard of a 1955 Les Paul Junior. When it dried, the abrasive powder was in all the pores of the wood. When he contacted me, I could feel the desperation in his words.

After an attempt to obtain Formby Buildup Remover which is not available in [redacted], I told him to go to a hardware store and obtain many cans of naphtha type lighter fluid and multiple boxes of coffee filters. He was to flood the board with the naphtha, immediately soaking it up with a filter. I told him to repeat the process 100 times. I told him that when it dried, the board would look like hell because of the missing oils. He applied Fret Doctor and the board looked as good as new, leaving him a very happy camper.

The tropical hardwood that needs oil the most is Ebony. Other woods may crack at some time in the future. Ebony will. Apparently, yours was in pretty good condition.

This is what I do.

Ed is right on about the ebony warning.  It looks like a solid wood, but its inherent brittleness can fool you.  Don’t forget to apply Fret Doctor to your ebony bridges and pick guards and tuning buttons and such.  My Sadowsky Jimmy Bruno shines now with all that ebony quenched and nourished.  My Clapton acoustic bridge went from a dull and chalky grey to a shiny and deep black ebony because of Fret Doctor.


I then asked Ed in email for more information concerning the process and expense of creating Fret Doctor and here is his kind reply — republished, of course, for you with his permission:

Most of the products on the market are essentially mineral oil with a scent, normally lemon, added. Mineral oil, aka: “Paraffin oil,” is a fraction from the distillation processing of petroleum. It coats the surface of wood and can make it look pretty. Real Lemon oil is steam distilled from Lemon peel, has an acidic pH of around 4.0. Get some in a cut, and you will learn that fact. It is a pretty good cleaner but I wouldn’t leave it on too long. Fret Doctor actually penetrates the wood. That is the difference.

FretDoctor is a mixture of entirely vegetable base substances, mostly plant oils, but also containing plant sourced emulsifiers and preservatives. Since I don’t make the stuff, I don’t know the formula. The oils come from all over the world and are quite expensive, especially when compared with mineral oil which is available in the drug store for a buck or two.

There was a time when most wooden woodwind instruments were made from Ebony. Any clarinetist or oboist who has a top of the line instrument can tell you about the propensity to crack. This is why, over the years, Grenadilla aka: African Blackwood, has been used as a substitute. I sell Grenadilla instruments and wouldn’t even want to stock Ebony products for this reason.


I finally asked Ed about purchasing Fret Doctor from his website and its general unavailability in the “big box” guitar stores online and on the street, and Ed agreed to let me share share this with you:

Because of the manufacturing expense, I can’t provide a 50% – 60% discount because it simply isn’t there. I have dealers in Stockholm, London, Singapore, Hong Kong, Kentucky, Missouri and elsewhere who will accept the lesser profit, primarily because they love the product.

If FD were to be placed on the shelves of a typical store, between bottles of other products, it would never sell. People assume they are all the same and buy cheap. If I raised the price and provided a bigger discount, it would be even more expensive. This is the problem with distributors. So, I do it myself, with guitarists around the world as an unpaid sales force. Considering their credibility when compared to music stores, that is probably the most effective approach.

Fret Doctor is an amazing product and Ed Boyle has dedicated his life to helping us get our guitars and other musical instruments in better shape.  Fret Doctor is now a routine part of every cleaning and strings change for me — and now, I hope, for you too!


Here’s a fitting, final, word from Ed on how meaning and perception can color how one treats and cares for their wooden treasures:

When I began, I learned that the word, “darken,” has multiple meanings. Darken can mean what FD does best: return the faded board to the way it looked when it was new. The color and grain come back.

Darken can also mean blacken. I know people who use black leather dye on a beautiful Brazilian board. Some use black shoe polish. Apparently, they want their board to look like a “1950s guitar.” In fact, many 1950s guitars had normal appearing Rosewood boards and the luthier or later owner(s) applied Linseed to them over the years. Overtime, Linseed oil oxidizes to a black color. Visit a museum and look at the old furniture. It is all near black.

So, someone who wants his guitar to look like a 50s guitar would look today, after all that oxidation, should use dye. If you want it to look like it did in 1950, leave it alone, which is my recommendation.


    1. Fret Doctor does pretty much work instantly in changing how the wood looks and feels. Then it does its due diligence and seeps in as much as it needs to so the wood is protected.

  1. This reminds me of the rosewood oil we used on the wooden equipment in our special room – it had to be applied each year to stop the wood drying out and to keep it healthy. We had a lot of wood – it used to take budgie days to do the complete task and was always difficult to schedule as most of it had to be dried outside . The smell was heavenly when it was completed though – SMILE !

    1. I’m so glad you took care of your wooden equipment. SMILE! Not many people know wood needs to be oiled and humidified and kept at a proper temperature at all times.

      Musical instruments are especially temperamental to weather and humidity and temperature changes. My first Martin guitar was kept, out of its case, near a huge window and steam heater for three years. The cracks in the finish were almost immediate. I didn’t know any better, and nobody bothered to tell me not do that. Some lessons are learned the hard way.

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