A new lozenge containing the amino acid L-cysteine is an effective, nontoxic smoking-cessation product, according to researchers in Finland.
At least two US experts are not convinced, however.
The study was conducted by Dr. Kari Syrjanen who, along with five co-authors, works in Helsinki for Biohit Oyj, the company that funded the study and markets the lozenge as Acetium.
L-cysteine is an amino acid that eliminates acetaldehyde, a compound in cigarettes believed to play a role in tobacco addiction by enhancing the brain’s responses to nicotine.
The research team recruited close to 2,000 cigarette smokers online and randomly assigned about half to use the L-cysteine lozenge with every single cigarette they smoked for six months, and the other half to use a dummy lozenge.
All participants kept an electronic diary, recording the number of cigarettes smoked and how much they enjoyed smoking each one.
Altogether, 753 people followed the directions for the entire study, and another 944 followed the directions most of the time, according to the report in Anticancer Research.
Over six months, 331 people who finished the whole study quit smoking: 181 (18.2 percent) who took the L-cysteine lozenge and 150 (15 percent) who took the placebo.
Among those who adhered strictly to the directions, 170 (45.3 percent) who took the L-cysteine lozenge quit smoking compared with 134 (35.4 percent) who took the placebo.
Less smoking pleasure and “smoking sensations changed” were given as strong reasons for quitting. Six percent of participants in the study reported adverse events (although the researchers didn’t collect the details), and the rate was about the same in both groups.
Dr. Scott Sherman, co-director of the Section on Tobacco, Alcohol, and Drug Use at NYU Langone Medical Center in New York called the study “promising” but said the lozenge “is not ready for prime time.”
The results are “modest,” he said by email. The researchers didn’t compare the lozenge to other smoking-cessation treatments, he noted, and it’s not clear if it would have worked as well if participants weren’t required to complete the daily diary.
The lozenge isn’t available in the US, and other formulations of L-cysteine might not work as well as the one that was tested, Sherman noted. “If the manufacturer wanted to sell the product in the U.S. and claim that it helps with quitting smoking, it would need to be approved and regulated by the Food and Drug Administration,” he said.
Martha Tingen, director of the Tobacco Control Initiative at Augusta University in Georgia, also noted study limitations; including the fact that one-third of the people who originally enrolled didn't actually participate.
Also, she pointed out in an email, “The study was based solely on self report. There was no face-to-face and no one checked participants’ blood, saliva or expelled air to see if they actually decreased or quit smoking.”
Most successful smoking-cessation interventions also include behavior counseling, she added. “If you have somebody you’re accountable to, it makes you feel better.”
Sherman said if one of his relatives wanted to quit smoking, “I would tell them to use one of the seven medications demonstrated in (the US) to be effective - nicotine replacement (patch, gum, lozenge, inhaler and nasal spray), bupropion and varenicline - in conjunction with a call to Quitline (1-800-QUIT-NOW), as that remains the best way to quit smoking.”
His preference? “The combination of a nicotine patch plus either nicotine gum or lozenge, particularly since they are available over the counter.”
The authors and Biohit representatives did not reply to requests for comment.
