Me, the person writting this guide, is not a doctor nor a physician. I'm just very experienced with chest binding (around 7 years old daily binding, tested multiple brands) and want to share my personal advices and warnings. Remember that everyone's body is different, not just in terms on chest sizes but also in physical health, sensory preferences and other forms of difficulties related to chest binding.

Do not use this guide as medical advice or for moral judgement. Thank you.

Be warned, I explicit talk about breast anatomy and may use terms as "masculinizing". While I don't believe a flat chest is inherently masculine, it is percieved as such by society, therefore someone with a flat chest will be more likely to be percieved as masculine than someone with visible breast.

This text is based on my own experience, what I've read from people who wear binders regularly of all sorts of body type and life styles, and also on scientific researches. Most of them has a similar conclusion : while there are real risks linked to the misusage of chest binders, they're mostly safe to use and actively elevate chest-related gender dysphoria. Here's a systemic review if you want a summarised version of a bunch of studies about chest binding.

A chest binder is a piece of underwear that covers one's breast tissue, and compresses it to give it a flatter appearance, by restributing and holding it in place. Unlike sports bras, chest binders were meant for the specific purpose of giving a more masculine appearance to one's chest. Currently speaking, chest binders are the most effective and safest way to flatten one's chest without going through breast reduction and double mastectomy surgeries, while avoiding the dangers of missuing bandages, medical tape and strong sticky tape.

Chest binders were at first design to help cis men with gynomastia (breast growth in males not induced by MTF medical transition), they're used a lot by transmasculine individuals, such as transmen, non binary transmasculine people, but also by women who wishes to present themselves in a more masculine way, or cosplayers. Some trans women and detransitionners may also use them during "boy mode" moments.

The most bare-bone chest binder has two fabric panels, with straps to keep it from slipping down.
The front panel is going to keep your chest in place and flatten the space between your breast by using a rigid fabric, while the back panel is stretch and helps spreading the compression all around your chest without completly squeezing it. Some chest binders are different and have their own specs, such ass:

● Long vs short : the long binder goes down to the hips (either offering a full body binding or just stops under the chest), and the short stops underneath your breast.
● Hooked and zipper : Contrary to popular believes, these options are not inherently less safe than the average binder. This rumour comes from a single, old chest binder company which hooked and zipper binders weren't safe.
● Sport : these binders compresses less for those who moves a lot while still binding your chest.
● Strapless : I don't recommand using these binders if you don't have a tiny chest.

Some chest binders are sensory friendly, meaning that their choice of fabric, the way the seams are done and how the compression is handled has been changed to fit those who's sensory needs are different and/or specific. Few brands offer tailor-made chest binders with your specific mesurements, be warned, they can get very expensive !

Wearing a chest binder is pretty safe, but it has some rules if you want to bind for a long time and keep your chest binder neat :

● Chest binders soaks your sweat and grim so much, which loosens the fabrics and makes it stink. Wash it regularly (once a day if you sweat a lot, once every three days if you don't).
● Choose the right size. I get it, gender dysphoria sucks and you want the flattest chest possible, but let me tell you, wearing a chest binder that is too small is going to hurt you. Sizing up is okay.
● Always buy reviewed bands. If your budget is tight, please seek out a second-hand option, but don't buy those 15 dollars shein/amazon chest binders, they're at best ineffective, at worst will hurt you.
● Make frequent pauses and don't wear them to sleep. Your chest needs to expend fully when you sleep. Wearing a chest binder during a short nap is fine, but a full night of sleep is not okay. Pauses are good to help you breath deeply, to let your ribs expend propely, and rest your back.
● Regarding DIY : Only sew your own chest binder if you are experienced in sewing !
● Do not layer chest binders. Using both trans tape and chest binders is safe, but do not layer binders.
● Seek out reviews. Not all chest binders are the same, and while some will fit you greately, some won't. If you have a bigger chest, consider that your morphology will impact how your chest binder will fit you.
● And lastely, please, understand and internalize that cis men don't have completly flat chest, and if you still see a bump, it is okay. Do not harm yourself to elivate gender dysphoria.

As of today, there are no scientific proofs that chest binders causes breast or lung cancer, besides, these cancers don't appear from chest compression (not any kind of compressions). However, chest binders can create some health issues or at least worsen the already present ones. Please consult the list underneath to see how and what to do if you have these health issues.

● Overheating : The most frequent negative consequence of chest binding is overheating. Binders can get quite thick, and if you wear a binder under hot weather, you increase the risks of a heat-stroke and dehydration. Fortunately, it's the easier issue to fix and prevent, you gotta drink more and take more frequent pauses.
● Asthma : Asthma is a spectrum, meaning that one's asthma can be managed much easier than someone else's, therefore I can't say definitvely if you should or should not wear chest binders. I'm asthmatic myself, and I can tell you that you can wear chest binders if they're proprely sized and you take frequent pauses. If you have frequent asthma attacks, it's better to wear a binder you can easily take off (zipper and/or hooks binder, with a preference for zipper for convenience). I heavily encourage you to take more frequent pauses too, as chest binders makes it harder to breath, even if you're healthy.
● Skin irritations and fungi : Chest binders soaks your sweat, and can rub a lot against your skin. If your skin is sensitive and prone to these issues, you may wash your binder more often and clean (or at least wipe) your skin before and after wearing them.
● Sensory special needs : If it's due to the type of fabric or seams, check out the brand's information on which fabric they use, or ask someone online if they may know it. If it's related to the compressing effect, please wear a lighter binder or size up.
● Rib and Back pains : if you're prone to back or rib pains, size up your binder or wear a light/sport one.
● Any other health issues related to pressure and/or attacks : Wear a binder you can easily and quickly take off, to prevent the worsening of your symptomes or crises/attacks.

Wearing a chest binder won't make you asmthatic, give you cancer, or immediately difigure your breast tissue and ribs. However, wearing a chest binder incorrectly has shown to :

● Change the shape of your rib cage (it may become concave) permanently
● Shorten your breath mid and long term
● Increase chest and rib pain mid and long term
● Mess with your breast tissue permanently
● Reduce the chance to get top surgery
But if you wear your chest binder proprely, even daily, you won't be likely to have any of these consequences permanently or long term especially if you plan on wearing chest binders for many year or get top surgery, this is why you should follow the general rules.

If you can't get a chest binder because you live in an unsupportive enviromnent, money, or just can't wear them due to health issues, there are some alternatives, but they have their drawbacks.
● Transtape : Transtape is a brand but I will use this term to mean the practice of using medical tape to flatten your chest. This technique is most effective on small chest, as it is easier to move your breast tissue if there's less volume. While it is possible to bind using transtape if you have a large chest, it is much harder, uses way more tape and the results are less satisfying than with a chest binder. Pros are : light compression that makes it easier to breath, better accessibility (if you can get the small sizes of tape), cheaper by purchage, waterproof, more discreet. Cons : skin irritation, hard to remove, more expensive if you bind regularly with tape, not suitable for bigger chests, allergy risks.
● Layering sports bras : All you need is to layer two sports bras that are a bit too small, and it will mimic a light binding effect. Pros : cheaper, more accessible, not explicitly trans-related, you can try them before buying them. Cons : not very compressive, you need two of them.
● Boned chest binders/corcet : A recent creation, boned-chest binders works by creating the appearance of a large ribcage. Pros : Lighter compression, tutorials are easy to find online. Cons : You have to learn how to saw and some materials are a bit hard to find, can't buy them as far as I know.
● Other tape, bandages, and else : Do not use them.

This section will only include binders that I have tested, meaning that it won't represent the whole brand. Also, I won't include brands that no longer exist or binders I don't actively wear or haven't tested recently. None of these binder sponsored me, they're my honest opinion. All photos used are available publicly on their websites.
Remember that my body is not the same as yours, my sensibilities are not the same as yours, therefore I might like a binder and you won't and vise versa. Here's what I can tell you about me and my body : I have a medium chest, I'm chubby, have asthma, light sensory needs and move quite a lot.