There are many threads on the boards about eating clean and juicing to improve acne. That is definitely taking a step in the right direction, but it's only taking a couple steps.
Everybody's unique makeup makes their acne unique as well. But there is no doubt acne is related to your health. If you are not taking care of your body, your hormones will be fluctuating. Yes, some people can do whatever they want and not have acne. That doesn't pertain to people who frequent this board, however. Genetics play a part in the hormonal aspects that affect acne.
You need to take care of your whole body. Juicing is great and has been effective for some. However, juicing is only putting in a small number of nutrients back into your body. Eating clean is great too and definitely is a win-win no matter what your acne situation. However, most people do not get in all the nutrients they need daily nor are they properly maintaining their body with regular exercise.
I use a health shake that packs dense nutrition into a single serving, more than most people get in one day. Ever since I started using it I noticed improvements in my digestive system, my mood, my energy. But I was also noticing improvements in my hair, my nails growing faster, my adult acne and redness improved greatly.
I've used this drink now for a couple years now, which I started to get me going fitness wise, and because I'm lactose intolerant and cannot use any of the products out there with dairy in them. In the last two years I've stopped eating red meat, stopped drinking Diet Coke, began exercising much more regularly, and dropped 22 pounds. Again, I've had the hair, nails, and skin benefits as well, but never thought to post them (I've been a member here for years) until now.
This wouldn't be a fast fix, but I do wholeheartedly agree with the other posters that acne is caused by nutrition issues with your system. What you eat affects your hormones. I also believe regular exercise is a piece of that nutrition factor as well.
As an example, many people who suffer from PCOS have acne due to the fluctuations of insulin caused by the consumption of too many carbs. Nutrition is huge for PCOS, but yet it's very difficult for many people to get their nutrition in check. My daughter suffers from PCOS so this is a road we have gone down.
I won't post what health shake I use here because I don't want to spam this board, but if you're interested, I'm happy to provide more information about it. Just send me a message. As reflected in my signature, I try to use more natural products. Our society wants to take a pill or slather on some gel to fix everything. Put in the work to reap the benefits.