@mtsumeb Your main photos of people training do not feature any of your designs - if your aspirational figures do not want to wear your designs, why should I?
Your logo looks like you knocked it out on MS paint or Microsoft Word, sorry! The garish colours and badly sized images of carrots and hearts...needs an overhaul.
The quotes arent particularly insightful, motivational or funny.
Who are you targeting? Currently looks like it's aimed for teenagers with the colours and style, therefore the price point is wrong.
Needs accurate sizes, length is important when it comes to gym wear so either have pictures of people wearing your items or state the sizes.
I'd be intrigued to find a guy who would wear this feminine design to the gym.
http://www.thefitnessfit.com/collections/mens-shirts/products/short-sleeve-mens-t-shirt-3
My piece of advice: would you wear any of these to the gym? If the answer is no, redesign.
What's your return policy? Do I pay return shipping, do you?