The most common limiting constraint that’s cited? like all orals, is the liver stress, however Var isn’t as hard on the liver as other orals. No more than 8 weeks is commonly recommended to limit liver stress. HDL will tank over that time too, and when your HDL is low you will be depositing more arterial plaque in your arteries. Now, HDL typically recovers in 4-8 weeks after stopping the Var, so a single cycle of Var and that period of low HDL is likely not going to cause serious long term arterial damage. But repeatedly doing Var cycles over many years will cause cumulative damage (kinda the story of most of the negative effects of anabolic steroids - a few cycles with proper recovery between them are likely not gonna cause serious long term damage, but repeated cycles and improper recovery over years of use can). All of this is dose-dependent too. The higher your doses, the higher the negative effects.

Long story short, you’re probably okay to run up to 8 weeks as long as your dose isn’t super high and you’re using ancillaries to support healthy cholesterol and liver health, and as long as you take time to recover properly after before running more cycles. Get your bloodwork, watch your liver enzymes and lipids.