Annoyingly Youtheory joint collagen advanced hides behind "proprietary" blends, and said blends do not add up to nearly enough to have the correct ingredient dosages. In fact only two of their ingredients can be properly dosed, the bromelain and the collagen. And whilst this will likely have some benefit for healthy joint cartilage, a lot of other joint supplements contain the same ingredients and more correctly dosed around the same price point. Meaning that whilst Youtheory joint collagen should have some benefits we don't recommend them against their competitors.
Unfortunately some of the best ingredients in Youtheory joint collagen are the ones that have to be underdosed. For example curcumin (the turmeric extract) has been well studied to be effective at reducing joint and knee pain and is particularly effective for inflammation, however, it requires 500-1000mg and it only makes up 20% of turmeric. In Youtheory's example the blend of 4 ingredients only contains 500mg in total of turmeric which means there simply isn't enough space as they'd need at least 2500mg for that one ingredient. YouTheory's Joint Collagen formula's not going to be effective for severe osteoarthritis, and certainly not for rheumatoid arthritis which requires even higher doses to have shown any efficacy.
It's also worth noting that YouTheory has some similar supplements such as YouTheory Joint Complex which are similarly underdosed and reliant on boswellia.
This is a pretty common issue with Youtheory products and Youtheory joint collagen advanced is no exception.
Customers reviews of Youtheory Joint Collagen Advanced aren't bad, they're actually pretty positive by Amazon standards. This is likely to be largely down to the hydrolyzed collagen. If you listen to reviewers who've tried other joint collagen supplements however, that's where the story gets a little bit different, with several complaining that it was less effective than their normal supplement.
In general YouTheory do create well packaged products and have decent customer service so there's no serious complaints there.
Hydrolyzed collagen 600mg - Hydrolyzed collagen has been shown in a couple of studies to have statistically significant results when it comes to improving joint health . It's not the best joint supplement for people who don't already have healthy joints in terms of the level of scientific backing and a lot of studies do show that the majority of collagen is broken down in the stomach and doesn't make it to the targeted area unless it's injected directly into the site. It's likely it has some impact, although it definitely isn't the best joint complex ingredient.
Proprietary blend 500mg
Boswellia - Boswellia is typically dosed at 100-200mg which would sit well within the reasonable range for this proprietary blend. That's about the only ingredient in here that is likely to be particularly effective however, and whilst it has been shown to have some impact on joint pain, in both people with osteoarthritis as well as people with injuries and otherwise healthy joint cartilage.
Cinnamon - There is a couple of studies that show cinnamon to be effective at improving symptoms of arthritis  however, the doses start at 500mg, of concentrated extracts. Added to which studies are limited, although there is generally a reasonable amount of backing to suggest that it should have some mild benefit for inflammation even in this dose. There are better options though.
Turmeric - As we mentioned in the intro, for turmeric to be effective it would have to be dosed at 2500mg and up. The Youtheory joint collagen formula can't possibly contain even remotely close to enough to have an impact on whether or not someone's joints hurt.
Quercetin - Quercetin is a flavonoid, several flavonoids do have a lot of benefits that make them a decent ingredient in a joint compound. However, there is a problem here, and that is you need about 2.5grams of it a day to be effective according to most recent clinical trials.  Once again for our Youtheory joint review it's not a bad idea, it's just not quite executed as well as we'd like it to be.
1 - https://pubmed.ncbi.nlm.nih.gov/18416885/
2 - https://pubmed.ncbi.nlm.nih.gov/29722610/
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777580/