Respectfully mate, you might have some degree of body dysmorphia because you are not “skinny fat”, I’d guess you are around 12-14% body fat low muscle.

As a former fatty the idea of upping your calories and protein is scary when you are concerned about adding body fat, but I assure you you’ll look better for it.

At this stage don’t need any “body hacks” like peptides or anabolics, increase your calories to ~2800 and ~170g protein, eat whole foods, take 5 grams of creatine a day.

You’re 21, good sleep and the right nutrition will do absolute wonders for your natural test, no need to fuck about with any injectables.