Question: Hey, I'm 14 years old and I want to know if I can build muscle without supplements, protein bars and shakes, or a hardgainer diet. Note that I currently have a daily intake of 50-70 grams of protein. I also drink 10 glasses of water every day.
Answer: Brigham, thanks for the question. It's an important one to ask before you even consider spending any of your hard-earned dough on supplements...
...So I'll get right to answering it – Yes, you most definitely can build muscle, and plenty of it, without any supplements. There are plenty of guys out there who take no supplements at all, yet they managed to upgrade their physiques from frail to freak-of-nature status.
The fact of the matter is that many (if not most) supplements on the market are garbage; and thus, only act as an alternative to flushing your money down the toilet.
I'm not saying that all supplements suck, because there are some great products that do help you build muscle. However, even the best supplements only give you a slight edge; and that's assuming you're doing everything else correctly to begin with (i.e. diet, sleep, training). See weight lifting supplements for more on this topic.
You also asked if you need to be on a "hardgainer diet" to gain muscle, but it's not clear to me what exactly you were referring to with this term.
If you were referring to the name of a specific diet system (e.g. Atkins Diet, Anabolic Diet, etc.), then the answer is no. There are a bazillion different diets systems out there that you could possibly use to gain muscle. On the other hand, if you were simply using "hardgainer diet" as a general term for a high protein/high-calorie diet, then yes, that is a requirement for building muscle...
...Although most gym-goers don't follow this practice, you gotta put some real effort into your diet if you want to gain more than just a minimal amount of mass. While training is essential, your diet can make or break your muscle building results.
As for how to go about making a basic diet plan, read this how-to bodybuilding diet article, and follow its guidelines for the "bulking" diet.
In terms of protein, unless you only weigh 50-70 lbs, then 50-70 grams per day is not enough. As you'll discover when you read the bodybuilding diet guide (previous link), you should increase your protein intake so that you're eating 1.0-1.5 grams of protein per pound of bodyweight, each day...
...This is where a simple whey protein supplement can be helpful/convenient, because getting all your protein from whole foods can be a little challenging.
But again, whey (or any other supp) is NOT a necessity. Although it may be a bit difficult to get all your protein requirements from regular whole food, it's far from impossible. As I mentioned in my article on article on whey protein myths, I did just that for about a year when I began lifting at age 15, because my parents wouldn't let me buy whey protein powder (they *thought* it was dangerous).
If you have trouble eating enough protein, and protein supplements are out of the question, don't fret. I have a few quick suggestions for cost-effective, easy-to-prepare and easy-to-consume foods that are high in protein: milk, eggs and canned tuna. They may not be the most delicious foods, but they get the job done quick, and without breaking the bank. For a much longer list of high protein foods, see muscle building foods.
It's great that you're getting into weight lifting at your age. Just be patient and don't be overzealous in your training by adding weight at the expense of proper form. I realize you didn't ask about training in your question, but I am making this point because you're 14 and more likely to push it past the limit. It may seem highly unlikely that you'll get injured, but just trust me on this – I ignored this advice when I was around your age and had to learn the hard way that I wasn't invincible.
But if you make proper technique a habit and remain committed to your diet and training regimen, you'll be an animal by the time you're in you late teens – with or without supps.