References
When it comes to our health, accuracy is everything.
With this in mind we have developed Quitzas algorithms directly upon respected and peer reviewed research papers. In the interests of safety and transparency, we have cited our sources for each metric Quitza provides below.

Blood Pressure Reduction
Mahmud, A, Feely, J. Effect of Smoking on Arterial Stiffness and Pulse Pressure Amplification. Hypertension. p183-7.
Carbon Monoxide Retention
US Surgeon General’s Report, 1988, p. 202
Circulation Improvement
US Surgeon General’s Report, 1990, pp.193, 194,196, 285, 323
Nicotine Retention
Research Report Series: Tobacco Addiction, National Institute on Drug Abuse, p34
Heart Attack Risk Reduction
Risk of Heart Failure and Death After Prolonged Smoking Cessation: Role of Amount and Duration of Prior Smoking Amiya A. Ahmed et al, p 54, 89
Heart Disease Risk Recudtion
Tobacco Control: Reversal of Risk After Quitting Smoking. IARC Handbooks of Cancer Prevention, Vol 11. 2007. p 11
Stroke Risk Reduction
Tobacco Control: Reversal of Risk After Quitting Smoking. IARC Handbooks of Cancer Prevention, Vol 11. 2007. p 341
Throat Cancer Risk Reduction
A Report of the Surgeon General: How Tobacco Smoke Causes Disease - The Biology and Behavioral Basis for Smoking-Attributable Disease Fact Sheet, 2010
Lung Cancer Risk Reduction
A Report of the Surgeon General: How Tobacco Smoke Causes Disease - The Biology and Behavioral Basis for Smoking-Attributable Disease Fact Sheet, 2010
Energy Levels Increase
US Surgeon General’s Report, 1990, pp. 285-287, 304
Average Life Duration Increase
Time for a smoke? One cigarette reduces your life by 11 minutes. BMJ: British Medical Journal. Vol 320. 2000, p53
Amount Of Smoking Related Deaths
Tobacco Fact Sheet 339, World Health Organization, 2015