Force factor alpha king supreme isn't a bad supplement, they just have a habit of annoyingly missing the mark. It's clearly a testosterone booster that's focused on the "ahem" evenings activities, rather than gym performance, and it's really close to being great. It just misses the mark and there are as a result better options at it's price point.
They almost nail the vitamins and minerals (they use the cheaper magnesium and this is unfortunately a laxative for about 10% of people), get the Ashwagandha root extract dose right, include a lot of good ingredients libido and enhanced blood flow, but go on to include a large amount of blood flow ingredients in the place of DAA (D Aspartic Acid) and Panax Ginseng which are two of the best testosterone boosting ingredients on the market right now.
The problem is it's trying to be two things at once, and as a result doesn't quite do either as well as you'd like. If you compare this to Prime Male for example, they split these two functions into two blends which allow for both a better all rounder and a better specialised option.
But, despite this, it is a decent supplement, and we don't think it's bad, just we'd recommend either a more focused testosterone booster or a more focused male supplement.
Alpha King Supreme's marketing focuses heavily on it's enhancement effects rather than being an overall testosterone booster. Which makes sense with the inclusion of Maca and Horny Goat Weed (we're less of a fan of HGW's inclusion). The inclusion of L Citrulline does help blood flow to the nether regions, but, the studies are from rats.  And the volume this takes up is very heavy, maybe it works maybe it doesn't. This is why we'd rather have seen DAA which also needs to be dosed around 1500mg.
In short it's libido claims are fine, it's testosterone booster claims are also fine. However, it could do better. As a muscle builder it's not great. It's ok in that boosting testosterone levels will have some positive impact, but they miss out on better ingredients for this.
Not dosing vitamin D high enough, missing optimal fenugreek seed extract doses and as previously mentioned DAA.
The mental clarity claims seem reasonable as a lot of the ingredients in Alpha King Supreme belong in a stress reducing nootropic.
We answer some of the most commonly asked questions about Alpha King Supreme
The reviews are pretty good, and as we said the supplement isn't bad so we're not surprised amazon has it at about 4* as does their website, whilst you can't trust the later amazons seem mostly real, and the main complaints are about stomach upset.
Alpha King Supreme vitamin blend contains B vitamins, magnesium, selenium, Vitamin D, Calcium (odd and unnecessary choice), phosphorus (same again) and zinc. Which is what you'd expect from a testosterone booster. Deficiencies in these can cause low test, and vitamin D supplementation has large benefits in athletic performance up to 5000mg. 
As for the choices of herbs in force factor alpha king supreme Ashwagandha root extract is proven to boost testosterone levels and reduce stress  making it a great choice. The most tested dosage is also 600mg, so it does seem like Alpha King Supreme have gone with the smart option here.
But horny goat weed and maca don't boost testosterone. Maca does help raise libido, in both humans and animal studies. Fenugreek seed extract has also been shown to raise test levels in double blind studies. The rest of the herbal extracts however, such as lion's mane, pumpkin seeds and nettles either do nothing or very little for test levels.
The nettle extract should have a mild boosting effect, the lions mane mushroom and pine bark are more of a mental clarity ingredient and pumpkin seeds don't really do anything. Both ingredients typically make it into nootropics more often than testosterone boosters, although there has been one animal based study that backs pine bark, but it was hardly convincing. 
So, as stated they missed out on DAA and ginseng, for no real reason, so we can't give force factor alpha king supreme top marks as a testosterone booster.
So close, yet so far, they had to include the 1500mg of unproven L Citrulline, it's a shame, other than that there's some minor dosage issues. For some reason Force Factor Alpha King decided that it needed to be different rather than good. And our alpha king supreme review reflects that. It's very close to being a good supplement, but we can't recommend it over Prime Male or any of the other competitors on our best testosterone boosters list.
In short, we're not mad we're just dissapointed by alpha king supreme.
Make sure you get the right testosterone supplement for you.Check Best List
1 - https://pubmed.ncbi.nlm.nih.gov/24372616/
2 - https://pubmed.ncbi.nlm.nih.gov/34202578/
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6979308/
4 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6170226/