Frequency claims
What is behind Solfeggio frequency claims?
Explore the history, modern claims and limits of the available evidence.
The key idea
The fixed Solfeggio frequency list is modern. It is not medieval and it is not physics.
Follow the process
- 111th century: Guido d’Arezzo, Ut-Re-Mi-Fa-Sol-La
- 2Relative pitch for sight-singing
- 31990s: Puleo and Horowitz
- 4Fixed tones from numerology
Historical solfège.
Benedictine monk Guido d’Arezzo used syllables from the hymn Ut queant laxis to teach relative pitch. There were no fixed frequencies in Hertz.
The modern list.
396, 417, 528, 639, 741 and 852 Hz were introduced in the 1990s by Joseph Puleo through numerology applied to the Book of Numbers, then popularized by Leonard Horowitz.
The “528 Hz repairs DNA” claim.
DNA repair is carried out by enzymes inside cells. Audible sound at listening volume cannot drive those pathways. Claims that 741 Hz detoxifies cells or 963 Hz activates the pineal gland have no biological basis.
What research does show.
A nine-person study found 528 Hz music lowered salivary cortisol and raised oxytocin. A 2026 trial with 162 students found higher BDNF and CREB, markers linked to brain health, after 528 Hz music, with no difference in test performance.
Sound can affect stress responses. A number on a track title does not determine what it does.