This thread is a perfect example of what is NOT A SCAM.
The vendor's name has been changed for illustration purposes because, again, this is NOT A SCAM.
1. Yellow NAD+ is not unusual, and is often considered normal. There is an almost unlimited amount of discussion on the internet about NAD+ color and what it may/may not mean. The fact that a vendor's NAD+ is yellow doesn't make it a scam.
2. Fluid color is not a lab test, especially with products like NAD+, anything containing copper, etc. (blue or yellow tirzepatide on the other hand is something to probably be concerned about, but still likely wouldn't qualify as a scam).
3. Even bad lab test results would still only demonstrate a bad product and NOT A SCAM.
4. People who probably shouldn't be buying certain products over the internet are always the first ones to scream "SCAM!" at the slightest thing they perceive as not being whatever their definition is of an ideal transaction.
5. Even if the OP didn't claim this was a scam and instead posted this as a review, it probably would have been disallowed without lab tests supporting their conclusion, especially since the product in question is NAD+.
The first reply containing "The yellow color indicates..." is clearly AI-generated garbage. Anyone relying on AI to help them understand such important topics like something they're injecting into their body should absolutely not be DIY'ing and should instead stick with licensed professionals and clinics.
The product may be junk, or it may be perfectly fine. Without independent lab tests, nobody can say for certain.
Anyone with difficulty understanding the differences between not understanding what they're buying, dissatisfaction with a vendor and/or their product, and scam should probably avoid buying these products over the internet. They probably jump to the same irrational scam conclusion if they order AA batteries from Amazon but accidently get sent AAA batteries.