The Sex Serum of Dr Blake (1970)

35mm film, colour, 1.85:1
mono, English

An American science fiction/horror film directed by Charles Nizet. The film was first mentioned in the 20 May 1970 edition of Variety under the title The Secret Sex Serum of Dr. Blake in a short piece on sex films being sold at that year's Cannes festival and it played under that title in during August 1970. It was re-released in 1973 under the title Heartbeat and was long thought to be a lost though a copy is in fact held in the archives of Belgian distributor Belfilm.

Plot Summary

Chinese secret agents have learned that the USA has developed a “serum of youth” and want it to keep their leader Mao Tse Tung youthful. The serum is injected into Dr Blake who transforms into a vampire-like creature.


Directed by: Charles Nizet
Ray Molina Productions, TWI National
Produced by: Ray Molina
Written by: Charles Nizet
Studio: ATF Studios, Las Vegas, Nevada, USA

Ray Molina (Dr Blake)
Philip Ahn (Mao Tse Tung)
Ern Dugo
Forrest Duke
Stan Mason (Inspector Brady)
Mike Zapata
Mike Meyers
Ebby Rhodes
Mary Martinez
Ray Molina Jr

Alternative Titles

The Secret Sex Serum of Dr. Blake – re-release title
Voodoo Heatbeat – re-release title


Uncredited writers in Boxoffice were generally impressed, one noting that it was a “very funny horror film” 1Boxoffice 28 August 1972 p.121 while the other felt it was a “fairly well-made exploitation picture that could appeal to both the horror fans as well as “cult enthusiasts.” 2Boxoffice 12 June 1972 p.4496



  • Boxoffice 15 May 1972 p.9 – note (Zapata Descendant to Star in ‘Voodoo Heartbeat)
  • Boxoffice 5 June 1972 p.W-3 – note (Hollywood Happenings)
  • Boxoffice 12 June 1972 p.4496 – review
  • Boxoffice 28 August 1972 p.121 – review
  • Daily Variety for April 19, 1972 p.2 – note (R films top ratings list)
  • Variety 20 May 1970 p.5 – note (No Surprises As Sex, Politics Rule Cannes Agenda)
  • Variety for April 19, 1972 p.22 – note (Restricted' Rules Code)