Solfeggio Frequencies Explained: The List and the Science

Solfeggio frequencies are nine pure tones from 174 to 963 Hz, each tied to a healing claim that only one small study in people has tested.

Solfeggio frequencies, explained in one line: they're nine pure tones, from 174 Hz to 963 Hz, each said to do something for your mind or body. The names come from a medieval hymn. The numbers come from a book published in 1999.

The tones are real, and you can hear one below. The healing claims rest on three small studies: one of nine people, one of rats and one of cells in a dish.

What are solfeggio frequencies?

Each one is a single note. Play 528 Hz and you hear one clear, steady pitch, close to a high C on the piano.

People often lump them in with binaural beats, which are two slightly different tones, one in each ear, that your brain hears as a slow pulse. A solfeggio tone is one note, and it sounds the same in headphones or on a speaker.

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The solfeggio frequencies list

Here are all nine, with the syllable each is matched to and what sound-healing sites say it does. The last column counts the studies in people we could find.

Frequency	Syllable	What it's said to do	Trials in people
174 Hz	none	Ease pain and stress	None found
285 Hz	none	Restore tissue	None found
396 Hz	Ut	Release fear and guilt	None found
417 Hz	Re	Help you through change	None found
528 Hz	Mi	Lower stress, "repair DNA"	One small study
639 Hz	Fa	Improve relationships	None found
741 Hz	Sol	Clear the mind, "detox"	None found
852 Hz	La	Wake up your intuition	None found
963 Hz	none	Raise awareness, "activate the pineal gland"	None found

The six in the middle are the original set. The other three were added later to extend the pattern, which is why they have no syllable.

Solfeggio frequencies explained: where the numbers come from

The word is old. Around 1025, a monk named Guido of Arezzo was teaching choirs to sight-read. He used a hymn to St. John where each line starts one note higher than the last, and he named the notes after the first syllable of each line: Ut, Re, Mi, Fa, Sol, La. That's the do-re-mi music students still sing.

Guido's syllables never had a fixed pitch. "Mi" is a step in whatever scale you're singing. The hertz itself is named after Heinrich Hertz, a physicist born more than 800 years after Guido.

The frequencies arrived much later. In 1999, Joseph Puleo and Leonard Horowitz published them in a book called Healing Codes for the Biological Apocalypse. Puleo said he was guided to the Book of Numbers, chapter 7, and reduced the verse numbers there to single digits. Six three-digit numbers came out, and he read them as hertz.

The arithmetic is tidy. Add up the digits of any solfeggio frequency and keep going until one digit is left, and you always land on 3, 6 or 9. 528 becomes 15, then 6. That pattern is a big part of why the set feels designed.

The numbers don't sit on a piano, though. In standard tuning, C is 523.25 Hz, so 528 is a little sharp. You'll often read that 528 is a perfect C in 432 Hz tuning. The math says otherwise: in that tuning C falls near 514 Hz.

What do solfeggio frequencies do?

Each one gives you a steady pitch to listen to. Three studies get quoted as proof they do more, and all three tested 528 Hz.

The nine volunteers

In 2018, a team in Tokyo played five minutes of soft piano music to nine adults, once tuned to 528 Hz and once at standard tuning. After the 528 Hz version their cortisol, a stress hormone, dropped. After the standard version it didn't change much.

The rats at 100 decibels

In 2019, researchers in Tehran played a 528 Hz tone to rats at 100 dB and reported less anxious behavior and more testosterone in their brains. That's far louder than you'd ever play a tone at home.

The cells in a dish

The "repairs DNA" claim traces to a 2017 lab paper in which human brain cells, damaged with alcohol, survived more often when a 528 Hz tone played. The paper counted dead cells. It didn't measure DNA at all.

For the other eight tones, we found no studies in people.

Solfeggio frequencies benefits: what the research supports

Music does help you relax. A 2020 review of 104 trials with over 9,000 people found that music lowered stress, in how people said they felt and in the body, heart rate most of all.

None of that depends on a particular frequency. So a 528 Hz tone can help you unwind, and so could 512 Hz or your favorite slow song. Pick the one you enjoy hearing.

A single pure tone is also an easy thing to rest your attention on while you breathe slowly, meditate or wind down for sleep. Here's 528 Hz from Lissa, a pure sine tone at exactly 528 Hz, so you can judge it by ear.

How to listen to solfeggio frequencies

Pick a tone by ear. Try a low one like 174 Hz and a high one like 963 Hz, and keep the one you'd happily hear for ten minutes.
Set the volume low. The tone should sit at about the level of quiet conversation.
Listen for 10 to 20 minutes while you breathe slowly, read or wind down for bed.
Use headphones or a speaker, whichever is comfortable. A single tone works the same on both.

If a high tone starts to feel shrill, switch to a lower one or stop.

Are solfeggio frequencies safe?

Yes, at a comfortable volume. A solfeggio tone is ordinary sound, and the only thing that can hurt you is the level you play it at and how long you play it for.

The studies above show why that matters: the rat study ran at 100 dB, loud enough to risk your hearing over time. Keep the volume low, take breaks on long sessions, and never turn a tone up to make it work better.

Questions people ask

What does each solfeggio frequency do?

Each tone is linked to a theme, like 396 Hz for letting go of fear or 528 Hz for stress. Of the nine, we found a study in people for 528 Hz only, and it was small.

What are the 9 solfeggio frequencies?

174, 285, 396, 417, 528, 639, 741, 852 and 963 Hz. The six from 396 to 852 are the original set. 174, 285 and 963 were added later.

Is it good to listen to solfeggio frequencies?

It can be, as a calm sound to breathe or relax to. Pick a tone you enjoy and keep the volume low.

How long should you listen to solfeggio frequencies?

There's no proven dose. 10 to 20 minutes is a comfortable session for relaxing or winding down, and you can stop sooner if the tone gets tiring.

Are solfeggio frequencies the same as binaural beats?

No. A solfeggio frequency is one note that sounds the same anywhere. A binaural beat is two tones, one per ear, and needs headphones.

Are solfeggio frequencies ancient?

The syllables are about 1,000 years old. The frequencies were published in 1999, and Guido's scale never had fixed pitches.

For the full history, from Pythagoras to Kepler, and every study in detail, read The Solfeggio Frequencies.