Jeff was amazed by how things played out. He was expecting the effects to change going forward but it seemed to be worldwide and retroactive. Repressing the ill effects made a complete socio-cultural shift to predominately smokers and a few science deniers who insisted it was unhealthy despite billions of people's first hand testimony and life saving interventions to the contrary. He was curious if he could keep loading up the positive side effects to the point that people avoid it again.
Jeff was irritated that he was shorter now having undone his most recent growth spurt and the beginnings of his sideburns. Looking through his profile, he was 2 pack a day smoker, and started at 12. Doing some math he was about a third of a year younger so without scientific intervention, people will still age and die naturally, albeit slower. He decided to fix the somewhat minor, but negative side effect of prolonging puberty first.
When he looked at his profile he saw that his actual chronological age had been reduced by 4 months not his biochemical age or whatever its called... Weirdly enough his birthday was the same so people just, lose time, disturbingly enough. That wasn't quite his intent... He wanted smoking to no longer cause the body to prematurely gain wrinkles, go gray, or sound like a gravel truck but instead made it so 5 minutes of smoking removed 3 minutes of aging and removed the side effects like cancer and reduced immune system that really kept people away.
He snubbed out his cigarette in his ash tray and unconsciously lit up again, a deeply ingrained habit in this timeline. He didn't want it to regress teens. He actually wanted it to impact teens even more but backwards until they reach 21. This way adults can't regress below 21, and kids will race toward 21 and age much slower once they reach it.
Some quick calculations told him that his 3 minutes of age modification per cigarette effected an hour worth of time per pack smoked. If he wanted it to be more impactful he would just need to make it effect kids more. Aging a week per pack would take 52 packs to age a year... It seemed like a lot but he had already forgotten he goes through 2 packs a day himself. Jeff smirked and updated the effect making smoking on those under 21 168x as potent and having the effect of aging naturally rather than regressing.
Clicking go. The world shifted again. This time when he looked up smoking it was treated like alcohol in that parents could allow it in their house but it wasn't allowed in public without parental supervision and he couldn't purchase it until he's 21. Old time home remedies for kids now included 3 cigarettes before a meal until the issue is resolved, this treatment claimed to cure acne, a cracking voice, low appetite, or fever.
Jeff looked up "kids smoking" on YouTube hoping there was a scientific summary of what society found out about it. It was actually insanely interesting. Jeff didn't mean to but reversing the aging effect meant that for those under 21, their body is temporarily thrown into overdrive. Scientists described experiments measuring individuals beard growth, without smoking and with smoking, finding that every 3 cigarettes is like fast forwarding 8 hours over 15 or so minutes. There was a timelapse video of some guy in a room for 8 hours, and another of him smoking three cigarettes, one after the other, still sped up but much less so. then it flashed to images taken immediately after the experiment and showed the "effect time had on him" being roughly the same.
There was societal confusion around the hard reverse upon reaching 21 and "Scientists are no closer to an answer now than when tobacco was discovered centuries ago." They listed everything they proved it wasn't related to, it wasn't a chemical in the plant, and it had nothing to do with how the body responded to certain individual chemicals, but as a whole, it just worked. It was touted as a gift from God.
Jeff further concluded the world for those over 21 is much the same. He did forget to make it do something or some things most would consider good... but that over time would become extreme...
Jeff came up with a few ideas.
1. An immediate moderate aphrodisiac followed by slight but permanent libido increase.
2. Slow but steady enhancement of secondary sex traits.
a) Males would become hairy regardless of genetics, much faster beard growth to the point that being clean shaven only lasts an hour or two till shadow is obvious and heavy, more muscular, deeper voice, bald if they would go bald eventually, taller if not fully developed.
b) Females become curvier, bustier, less hairy, more attracted to the traits the males gain, thicker head hair.
3. Slow but constant muscle gain eventually leading to becoming musclebound if left unchecked.
Jeff reached for his cigarettes before realizing he didn't smoke in this reality. The smell permeated everything and seemed stronger than before. Because he could remember the other reality it was able to act like a trigger, he reasoned. Thankfully it should be gone soon, and relegated as a temporary therapy. He stood up to check his height, and touched his sideburns to check that he was back to normal and he was. Thankfully he had also removed all effects from second hand smoke so living in a two smoker house won't have any impact on him at all.
Jeff just couldn't figure out which traits he wanted added nor where to draw the lines in the sand. For example, 1 pound of muscle per cigarette? Per pack? Per carton? Or maybe it should go off of time. If you smoke at least X per week, month, or year gain Y lbs...
He didn't want to immediately ruin lives, but he also didn't want society to be built around how much tobacco it could harvest and inhale. Though he loved having his grandpa back, this shouldn't be a fountain of eternal youth and the refinement, condensation, and administration of tobacco smoke to maximize youth seems like that exactly.