Honestly I don't feel anyone here has given you an adequate answer.

THC binds to Estrogen and progesterone receptors in your body; albeit very low. Estrogen (above normal/in excess) in males is responsible for weaker bone mass which results in lower muscle mass since the amount of muscle you can maintain is directly proportionate to the amount of bone mass you have.

Estrogen is also responsible for decreased metabolism and making your body predisposed to storing food into fat cells rather than trying to utilize that energy (part of this is also contributed to lower metabolism).

In addition progesterone can aromatize into estrogen; which can be even worse. Ever heard of bitch tits.. well that usually happens due to hormones that aromatize in the male body. This sudden build up of 'female' hormone will create a lump in your chest/breast. This is breast tissue forming. The reason this happens is because just like females, males have the exact same glands in their breasts as women. Theoretically men can lactate and breast feed. Yep yep.

Marijunana has also been prove to shrink testicles (as much as I hate to admit it, mine have definitely gotten smaller since I've become a daily smoker). The testicles are the main part of the male body responsible for testosterone production. Naturally if you inhibit these then you lower your total free test. in your blood stream. This is very important in strength/mass gains.

This could be offset by something called HCG (Human chorionic gonadotropin) which is a hormone that is extracted from pregnant womens piss. However this is illegal without a script and I'll stop talking about this then. Basically it tricks the body into thinking your pituatary gland is releasing a hormone called luteinizing hormone (LH) which in turn signals leydig cells throughout your body to produce testosterone. *note* HCG is only beneficially in instances where your testes shrink and can only be prescribed by a doctor. Which I'm 99% sure won't happen as they typically don't prescribe it to men.

The reduction in testosterone production leads to loss of lean body mass as well as becoming predisposed to storing food as fat.

With all that said, The occassional joint will not harm you at all. Even smoking daily would not harm your strength and mass gains due to the amount of thc that binds to the estrogen and progesterone receptors in your body. Additionally if you're currently active and working out then you are off setting any negative sides marijuana has sine you're increasing testosterone production anyway naturally.

There are 3 things you need to have in check to gain mass/strength:

1. Diet. This is the key component. Diet diet diet. Muscle mass is about 70% diet and about 30% lifting weights.

2. Proper form. When working out lifting a light weight with proper form and proper eccentric/concentric timing is much more important than lifting as much weight as you can. I roll my eyes at idiots at the gym who go and load 400lbs on the bench press only to see them with their feet hovering off the ground and their back arched upward as far as they can. This is horrible form and just looks stupid to a trained person.

3. sleep/rest. Your body gains strength/muscle mass when you are sleeping and rest. This mostly has to do with D wave sleep and release of GH which in turn triggers the release of IGF-1 (insulin like growth factor -1). These hormones in combination of testosterone and several other smaller hormones that are responsible for muscle/body repair. Get about 8 hours of sleep a night (this is enough to compete about 5 cycles of sleep. 1 cycle, all the phases of sleep including rem, can be completed in about 90 minutes if memory serves me correctly). Try to catch a nap if possible too.. a 90 minute one is best naturally.

Good luck on your gains :thumbsup: