Although I have been vaping over a week now I still get asthma attacks, occasionally as bad as when I was smoking. I have tried a couple different juices and brands but does anyone have any suggestions of suppliers that sell juice with the least amount of irritating contents?
Try ecopure from intellicig. It's slightly more $ but you can mix it with their mixer and double the quantity. There isn't a cleaner e-juice. It's made in the UK.
You might also want to either blow out the primer (if you use carts) an extra time, try the CE-2 to 4 no filler carts or switch to 501s or atomizers. Cartridges don't work. You could be allergic to the fluff in the filler - avoid dark colored e-juice and lower your nic. The nic will constrict your airways more the higher the level.
Technically, you are taking your chances to vape with asthma the same as with analogs. Your lungs need to breathe 100% air all the time but you can minimize the effects for a while. Til you feel ready to stop vaping, keep your asthma medication more handy. One of the myths about vaping is that is lessens asthmatic reactions. There's no cure for asthma and the best treatment is breathing warm, dry air through a mask. You should follow up with the doctor that treats your asthma before taking anyone's advice. If you have allergic asthma, you could be allergic to the FOOD flavorings and need testing to determine that.
You are always safer with non-tobacco flavored mild mint, which is the closest flav to - BUT IS STILL NOT - a medicine when vaped. None of this stuff is proven safe period but with asthma you need to first make sure you aren't allergic to ANY of the flavs. iow, you are only safer with zero nic/no flavor e-juice. Anything else, you run a far higher risk of having a life/death severe attack - If I were you, I'd only vape outside of an ER cause you have no time to waste if your rescue inhalor fails to clear up a food allergy in your lungs.
Seriously. Only your asthma doctor can help you feel safe-r vaping. People without asthma are having reactions to this stuff. Just you can get a much clearer answer from intellicig about what is in the ecoPure. Look for Purevapor also. I think they carry it also. I've tried it and it's thick but as clear as water as I've seen any e-juice. Take a bottle of it to your asthma doctor. they might be able to do a skin test to make sure you're not allergic to it. afik, measuring your allergies is the only way to determine (and avoid) having both asthmatic and allergic breathing reactions. Together, they can kill you so til you get around to it, talk to your pharmacist about fast acting (like in seconds) allergy meds or vape outside an ER and check with your doctor. You don't want to play with this stuff.
You might want to just use your e-cig to lightly blow air on and (you don't want to hear this but...) get a patch until you are certain you have no food allergies to any flav by any vendor.
If you become a statistic to avoid your md or more personalized tests, we're never going to know your opinion of the safest e-juice.

Be extremely careful, ok and ask on other forums.
You can even probably reach your doctor on call and ask. That is my best advice. Pick up the phone and consider it an ER question - your doctor will understand and you'll have a better, safer weekend. Tell him/her what juice you have now and that you asked about your asthma and vaping on-line - we're not doctors but we do care and every case of asthma is different. You need personalized advise. These are just some examples of what might be advised to you, and some things that
might save your life, if you can't control the vaping until you do what your doctor says you must.
I'm trying to be supportive though it sounds like a lecture. Only asking you push yourself to call your doctor on call and if you don't have a doctor you can be seen one at any hospital 24/7/365 for free. I'm only pushing you to do that much. k? It's not supposed to feel irritating to vape. Your body is telling you something. Listen to it. It's about your life's breath.
Of course, I'm assuming you decided to vape over smoke analogs to improve your health??
If you get to freaked out to call your doctor, pm me or a forum moderator or ask for help from a family member or friend. I'll call him/her for you. You might just need a different or stronger asthma med and get it worked out within an hour. I really don't know but that's a very real possibility. You're not going to know until a licensed doctor tells you. Pharmacies open in just over an hour.
Hope you get it worked out with any of these suggestions. You can't rely on anyone being on-line when you need them. Start with family and friends to get in touch with your doctor, asap. IT'S NOT SUPPOSED TO FEEL IRRITATING - EVER!