Never took slin but know a few guys who have and they gained considerable amount of weight and even strength on it ,now ,when you come off slin is it just like gear? if you come off completely do you lose a lot if not all your gains ?
They can be as permanent or temporary as gains from anything else , it depends how you use it
If you use it right and don't add on a ton of sloppy weight then you can definitely add lean tissue with it the same as if you did a cycle of AAS.
It can cause a significant amount of water retention which lead to weight gain , but also strength and endurance as well as nutrient absorbtion.
If you use that increase in power to nutrition to force growth then it will be more permanent
I find gains are only as permanent as one digestive system, hormones, training etc. allow them to be. Muscle can be maintained to a degree with less then it took to get the muscle there. But all things fade and have an expiration date. Just enjoy it while it's there.
^^^it's already been said above ..but i'll try to condense it again:
►your physique is a results of a combination of factors:
-a given amount of calories
..& their macro ratio
-a given given amount of stimulus
..& the particulars of that stimulus (..one example: PL vs BB training)
-a given amount of rest
-a given amount of drugs
..& the characteristics/synergies of those drugs
^^^this is just a short-list of the most basic "influencers"
(..age ..drug duration ..drug tolerance ..endo/ecto/meso ..genetics ..predispositions ..health ..etc etc etc ..are "some" other things that play a part)
►any change in the equation that you employed to achieve a certain look/physique; affects & changes the results
..these "changes" may manifest faster for some than others ..but they are eventual when you subtract (..or add)