Taking a lot of Supplements is not the answer!
I've been active on this site for a while and about every 1 to 2 weeks I see some teen kid ask about a testosterone or steroid. Or asking the question 'what will get me big fast'. Many beginners and teens, hell everyone looks at Muscle and Fitness, Flex and Men's Health magazines and see all those big, tough muscular guys advertising bodybuilding supplements to reduce fat, make you stronger and to make you bigger.
This is all-good and gives you great motivation but young teens like myself once did think that the supplements make you big. Little do we know that those professional bodybuilders do a hell of a lot of hard work in the gym and most properly take a few things that they do not advertise.
You must realize that to get big and look good you must do the hard work- you must pay your dues first! Then you will reap the rewards so to speak.
What I am trying to say is if you're under 19 and haven't been serious about lifting weights before, but you are now, start weight training first for about 2 - 3 months before buying supplements. Also get you're diet on track, but that's a different, yet important, topic.
If you have never lifted seriously before you will make gains, you will make gains in your size, fat loss and muscularity in the first 2- 3 months that even without supplements you will notice and so will all your peers. After the first 2 - 3 months you will steady out and struggle to put on the same gains as the first 3 months.
After paying your dues for the first 3 months, lifting heavy and safe doing all the compound exercises to put on the mass.
Then consider your supplementation.
Protein
You should start with the most used supplement Protein Powder. Buy some protein powder first and start using it. Take it 2 - 3 times a day. This will help rebuild the muscle and promote muscle growth, as well as help meet your daily protein requirements.
Creatine (Monohydrate or Ethyl Ester. I recommend Mono)
Then if you want, get some Creatine. Creatine is produced naturally in the body, although in minimal amounts so taking creatine will give you greater energy in your workouts and your muscles will grow. Creatine has been researched and has shown the best results. The number of compliments it has received has won the world over. It is the most popular supplement going. Creatine does have a couple of drawbacks. However, creatine maximizes water intake by the muscles, meaning you have to drink more water (1-2) gallons per day.
^^Those are the 2 main supplements I would recommend for a teen or beginner. Maybe Multi Vitamin or BCAA, but these 2 I talked about are very helpful.
I just think that kids workout to take supplements these days. But supplements aid your diet and workout.
There is one thing that is EXTRMELY that supplements will always be inferior to something and that is your diet. Probably 70% of teens don't diet and eat poorly. Although this is a differnet topic, it is a lot more important than supplementation. Without a strict diet for your goals, minimal or slow results will occur.
So.. I hope teens my age read this and realize that taking all these supplements aren't what make you big.
Main factors for everyone IMO.
-Diet
-Work Ethic
-Dedication
-Discipline
-Proper Supplementation
Hope this works/helps.
__________________
Ipsa scientia potestas est.
Proof that hard work grants success:
Postulate 1: Knowledge is Power
Postulate 2: Time is money
Postulate 3: Success is measure by wealth
In physics,
Power = Work / Time
Substitution dictates:
Knowledge = Work / Money
Solve for Money which = Success:
Money = Success = Work / Knowledge
Thus, success is determined by the amount of work you put in so long as you maintain a certain level of knowledge :) | 
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