My daughter is 18 years old and overweight. She has decided to join a gym. Would taking any supplements advisable since she has started working out?
Please not. While there might be an argument if she starts serious competitive weight lifting, I guess that the question would've been asked differently then. If she is overweight, she has to relearn how to eat properly and develop a healthy relationship with food.
If there are no medical reasons, don't waste your money. Learn how to eat everything you need instead. A proper diet has a good mix of protein, fats and carbohydrates. She needs the right kind of fats and carbohydrates though. Maybe try reading what the who has to say about it: http://www.who.int/mediacentre/factsheets/fs394/en/
I'd only give that article a 7/10 but what they propose is a million times better than the average nutrition. If you want to learn about how to eat right, please inform yourself. But this isn't the question. Btw, I recommend counting those calories (or joining a commercial program I'm not gonna advertise, but counting them is free). Most if not all people that have never done it have no idea how much they are actually eating. It really has two purposes: it helps you be at a good caloric deficit, neither too low nor too high, and it educates you.
Now back to supplements: if she eats right, why would she need to supplement her nutrition? If she eats e.g. vitamins, she doesn't need to take them in pills. Same goes for those 'healthy fats'. No pills can substitute for a bad diet. This is the wrong message: I don't need vegetables because I take some vitamin pill, let's have some chocolate instead. Eat vegetables. Oh and of course enjoy what you are eating. Nobody enjoys taking pills.
Protein powder, well, is she trying to gain as much muscle as possible? Is she a vegan? I could see an argument if she was. However, those shakes have a lot of calories. Have some fish now and then. Eat lentils. Beans are great. Personally I don't like turkey, so have some chicken. sausages burgers or deep fried chicken not so much, they are mostly fat. If you eat right and are not trying to be a bodybuilder, protein shakes are just a lot of calories that leave you hungry.
A word about creatine: it basically makes you perform better, let's simplify and say it makes you stronger, requiring you to lift more weight and train at a higher intensity to have a training effect. Chances are your joints will thank you later. If she has any orthopaedic issue, well, good luck. So unless she is an advanced, maybe even competitive lifter ... For a 18 year old girl just starting out at the gym, why should she even consider it? So she can (insert some exercise) with more weight in combination with the bad form she has as a beginner? Is she really into bench pressing, heavy squats, that type of stuff?
Do two things:
Make this question to a licensed professional who can see your daughter in real life (doctor, nutritionist, even a personal trainer). Free and general advice have either great or terrible effects, depending on so many factors. A doctor might cost the same as the supplements and have better results than any advice here.
Exercise with your daughter, or make sure she has a regular exercise partner. Peer pressure has a great effect on most people, as it will not only motivate her to follow the exercise routine but also follow an appropriate diet, which is better than supplements (as mentioned by others).
Creatine monohydrate, 5 grams per day, is beneficial in multiple respects and across different fitness goals, especially resistance training and high-intensity interval training (HIIT).
Protein supplements such as whey protein powder can be beneficial across different fitness goals, too, especially any kind of resistance training.
For further reading, please see "Stop Wasting Money - Nutrition Supplements that Actually Work".
I'm going to go against the grain a bit here and say DO get a protein powder for weight loss as long as you understand how it's going to work:
Muscle burns more calories than fat... what this means is a muscular person eats more and burns more calories while a person with a lot of body fat tends to pile it on. Muscle is easy to build but hard to maintain, so sustainability is key (think low impact).
What the protein powder would do here is help build the muscle that will then burn the calories, make sense?
Creatine is a step up from protein powder and is generally for more serious body builders / athletes. I'd work my way up to that one in lieu of increasing my workout time (ex. switching from low to high impact > bigger reps > more muscle tear > more healing > more muscle bulk)
Also, I've never heard of anybody taking Creatine for cardio (which would get you the most weight loss), so there's that.
The only thing a beginner need deadly in the gym is water. Let her find suitable amount of water being consumed per gym visit, and appropriate consumption schedule. For example, I get my best felt if I get all the water a bit later after the workout, some of my friends can't stand workouts without sipping water in process, etc.
So, just water. And her patience, of course, as you start seeing reasonable results after 6 months of gym, not faster.