since anyone can return anything on amazon for any reason, how do you make sure the helmet you get from amazon is safe to use? (retailers like REI claims they destroy safety equipments so that at least sounds safer)

Look at protection ratings, not what is available on Amazon.

All bike helmets sold in America must meet the CPSC standards. If you buy it from Amazon it should be fine. If it what you receive appears to be a used/returned/damaged helmet, simply return it.

Bicycle Helmets Business Guidance | CPSC.gov

I'd like to think that a helmet damaged enough to be unusable would be rather obvious. It isn't a CPU.

All bike helmets sold in America should be CSPC certified according to the law but the stuff on Amazon doesn't conform to the rules and doesn't make for a safe helmet. They have the moral scruples of a fetid potato. They have more money than the GDP of most countries yet cannot treat employees like humans. They don't care about selling you a safe helmet.

Go to your local shop try on some helmets and find one you like.

I am going to add a proviso: Cycling helmets can provide protection if you should have a fall, but they are not "bulletproof" . I have been using a cycling helmet for a half century. I don't regard it as a protective device, but only as a last chance if I don't ride as carefully as possible. Over those last 50 years there were a couple of times when I might have whacked my head on something during a fall, but nothing that might have been life changing. Helmets help, but nothing can substitute for riding carefully
This is from someone who did bike races for 20 years

Good advice.

OP and other BF posters should note that questions like his on "what should I buy" will often be answered by shills for LBS and the products sold by them and spend umptyeen electrons on bad mouthing the competition that is eating their lunch. Some will even tell him that he should also suspect any helmet that might be past an imaginary and arbitrary "safe for use by date."

There isn't anything inherently unsafe in buying a helmet from Amazon. Use common sense. Sold and shipped by Amazon is your best bet. Sold by XYZ for $15 and shipped from China, maybe not. You can also buy functional helmets at Walmart, Target etc. If you ride for more than an hour or so, things like fit, ventilation and weight become more important and you might want to devote more effort to your search.

That gets us into a whole different discussion (aka "The Helmet Thread"). But since you opened the door - my helmet has hit the ground fairly hard on several occasions - two in particular. Helmets were bashed, but I did not get a concussion. In one of these cases, I went over the bars at 27 mph.
Helmets FTW, as far as I'm concerned.

If you are in the USA, you should at least make certain it has a sticker inside that says it complies with CPSC standards. Though that's not fool proof if you don't know that the seller and manufacturer are trustworthy.

If the helmet fits well, then it's up to you and whether it worries you. Even the best helmets aren't going to protect you from every possible type of blow to the head. So all you can do is mitigate the risk.

I'd at least recommend a helmet that provides MIP's protection. They can be had for less than $100. But even if you don't want to spend that much there are plenty of cheap helmets that provide good enough protection. Even the Bell helmets that you can get a Walmart or Academy sports. At least then you can try them on and see how they fit.

I would be very careful about buying a helmet on amazon. From what I have seen, you probably can tell once you receive it, but it requires some amount of scrutiny.

I guess I'm a shill for my lbs, because they have cheap helmets that I know are actually made by the manufacturer the box says they are made by. There are literally tons of counterfeit products shipped by amazon every day. Just ask shimano.

I'd be wary of helmets from Amazon, clearly not all of them are up to par, who knows what other brands there are also trying to slip by with something that doesn't meet requirements: https://www.bicycleretailer.com/prod...amzimo-helmets

A helmet is something you wear a fair bit, and an extremely cheap one is more likely to be uncomfortable. I'd recommend shopping somewhere you can actually try the helmet on first, you are much more likely to wear the helmet if it is comfortable.

that's what i was thinking before too but heard that regardless of who's the seller, the products are all in the same bin...

I've been assuming we're talking about the half dozen known brand helmets. If you are looking at Ali-type "helmets" I'd pass, regardless of the seller.

Yes I was looking at the well known brands with MIPS

What is not being said, or understood, is that Amazon doesn't actually sell anything. This is especially true for bicycle accessories.They facilitate the advertising, purchase, and delivery process for the very same retailers (and lots of others) that you know: Jenson USA, Modern Bike, Bicycle Outfitters, etc.) you could order a helmet directly from a retailer OR you could order if from the Amazon entity. If you look, you can see, and sometimes choose, which actual retailer you want to get the product from via a (possibly) local Amazon warehouse. You could potentially get a previously purchased and returned product in either scenario. As others have said, a used helmet, even slightly, should be easy to spot.

I can usually tell when/if the product I have gotten from Amazon was previously purchased. That really chaps my hide when it was sold as new. In some cases it is just not worth the hassle to return and re-order. If it was a helmet, of course, I would be evaluating the situation with safety in mind. For the last year or so, I have saved as much as 50% on some things that I buy on Amazon by actively choosing to buy products that have been returned after just one use ('like new'), refurbished and sometimes flat out, used. If I can save 50% off the price of a room fan or iPad, I'll definitely buy used. Shame went out of my game when I retired and went on a fixed income. Bed linen or underwear, I'll buy those new, thank you. I still have some dignity left. FWIW.

Giro Register MIPS. Don't argue, don't think about it. Just buy the damn helmet. Here, I'll make it easy for you.

The essence of all the pitches and shilling for arbitrary helmet replacement sales! The basis of almost all helmet promotion found on BF and elsewhere from "enthusiastic" helmet promoters.

Try milk in your Cheerios instead.

Anyone who knows me (and you should) knows I am far from an "enthusiastic helmet promoter". I bought my first helmet in 2005 under duress, because a tandem club ride my wife and I wanted to participate in insisted on them. But since I had the damn thing I put a mirror on it and I have to admit it, a helmet is a handy place to mount a mirror. I still have that helmet and only replaced it last year when DW lost hers (also from 2005 and worn everyday since) and we wanted a matching set. She researched and settled on the Giro Register (MIPS!) and I trust her research ability. The o.p. wanted a helmet. Mine is not to reason why. The Giro is a solid choice.

That's how I read your post: As an endorsement of a known brand (which the OP says he wants) that has MIPS and is available at a reasonable price from Amazon (which is also what the OP wants).

Leave it to the perennial, "angry old man" to read it as some sort of preachy post about wearing a helmet. I have always wondered what in the world hurt him so badly.

I don't have much trust in Amazon when it comes to policing third party vendors. Amazon just doesn't care that you might be buying crappy products. Yes it is the front end for some known vendors; why not buy directly from them? I'm confident that the bike mail order places (or your local bike shop) can use the money more than Jeff Bezos.

I didn't know that Modern Bike sells through Amazon. I buy lots of stuff directly from them. They are my go-to source for the specific things that are not necessarily carried by my LBS.

You didn't mention that lots of brands also sell directly through Amazon. For example, Giro, mentioned by others in this thread, has an Amazon storefront

Don't flatter yourself, I don't know you or care about your past posting history. My response was to the helmet buying "advice" that you actually posted on this thread.

I really hope that's not the case because if you're being truthful then you are even more of a curmudgeon than I thought.