What Solfeggio frequencies actually are

Today the term refers to a fixed list of tones promoted for wellness. The most common set is 174, 285, 396, 417, 528, 639, 741, 852 and 963 Hz. They are often paired with claims like “liberating guilt” or “DNA repair.” These numbers are not a traditional musical scale. They are a modern sequence assembled around numerological ideas.

Important distinction: solfège is the medieval sight-singing method with syllables do re mi fa sol la ti. It teaches relative pitch and does not assign specific Hertz values.

Who came up with them

The core set linked to 396 through 852 Hz was proposed in the 1970s by Joseph Puleo, who said he derived the numbers using numerological reduction of verses in the biblical Book of Numbers. The idea was popularized in the 1999 book “Healing Codes for the Biological Apocalypse” by Leonard G. Horowitz and Joseph Puleo. Later promoters extended the list to nine tones by adding 174 and 285 Hz.

Are they ancient Gregorian chant tones

No. Medieval chant used modes and relative pitch. There was no universal reference frequency in the Middle Ages, or even consistently into the 19th and early 20th centuries. The modern A equals 440 Hz concert standard was formalized only in the 20th century. Assigning absolute numbers like “528 Hz” to medieval singing is anachronistic. For orientation, at modern equal temperament 528 Hz is a slightly sharp C5 and implies a concert pitch around A equals 444 Hz, which again shows these are modern choices rather than preserved medieval tunings.

Is there an objective scientific basis

For the specific claim that these exact frequencies have unique healing properties, evidence is weak. A few very small studies report short-term changes in stress markers or mood when comparing different tunings, but sample sizes are tiny, methods are limited, and results are mixed. Claims such as “528 Hz repairs DNA” do not rest on robust, replicated biomedical research.

For music and health in general, there is better evidence. Music therapy and listening to calming music can help with anxiety, pain and well-being in some settings. These effects do not depend on the Solfeggio list and are not unique to those specific Hertz values.

Bottom line

Solfeggio frequencies are a modern numerological construction, not ancient fixed pitches from Gregorian chant. There is no solid scientific evidence that the specific numbers 174–963 Hz have unique biological effects. If you enjoy them for relaxation or meditation, treat them like any calming music, not as proven frequency-based medicine.