That depends on which of the Weider Prime Testosterone Support claims that we're actually looking at. If you have low testosterone caused by a deficiency it addresses (Vitamin D3, Zinc or Magnesium) then yes, it could help you lose weight, improve lean muscle mass and give you a performance boost. Beyond that the benefits you'll be getting largely come from Ashwagandha extract. Whilst it has been shown to raise test, improve performance and reduce cortisol (stress hormone) build up, it would be notably cheaper to just buy it as a stand alone supplement rather than as Weider Prime. But, yes as more than half of the US (90%  by some studies, largely made up of Vitamin D) have at least one of these deficiencies it should actually work.
Customers reviews of Weider Prime are mixed, there's a lot of what appears to be review spam on Amazon, although a decent amount of legitimate looking positive reviews. As you'd expect most of the negative reviews of Weider Prime are simply people saying the supplement doesn't work. Which is what you'd expect, with very few complaining of Weider Prime side effects, which is actually surprising for and Ashwagandha based supplement as some gastric distress is not too uncommon. Weider Prime is a lot of men's first testosterone booster, which tends to mean that they're well received vs not taking any supplement at all.
The most commonly asked questions about Weider Prime
Yes, excluding the risk of allergens Weider Prime should be safe for human consumption. Some people will experience Weider Prime side effects, but these are typically limited to nausea and stomach pain which can often be mitigated by taking Weider prime Testosterone Support with food. That said, supplements are not regulated by the FDA in the same way that medications are, although all of the ingredients have been deemed fit for human consumption.
Vitamin D 400ui - Weider Prime includes 100% of your recommended daily intake of Vitamin D. The interesting thing is that taking more than the RDI can be incredibly beneficial when it comes to athletic performance and building lean muscle mass.  It has also been shown to dramatically increase free testosterone levels in deficient men and moderately increase it in none deficient men as well. It's a good inclusion, but they could've added more for a supplement focused on helping you build lean muscle.
Vitamin B6 10mg - This is a relatively high dosage of B6, although it's commonly found in sports drinks to increase energy. It does play a roll in testosterone production, although a deficiency that could cause an issue is relatively rare.
Vitamin B12 120mcg - Pretty much the same notes as Vitamin B6 in terms of how it relates to testosterone and performance boosting.
Calcium 35mg - This is only 4% of your RDI for calcium, whilst it is important for testosterone, we're not sure why supplementing this low amount would be necessary. It won't make much difference, several supplements do this and to be quite honest we're sure that it's only done to add another ingredient to the box.
Zinc 15mcg - This is 100% of your Zinc daily needs, and that's quite important for a testosterone booster. Even a very small deficiency can lower testosterone production severely and supplementing men with zinc deficiency and low testosterone is very effective at dealing with the issue. 
Chromium Picolinate 200mcg - Chromium has been shown to help increase weight loss in active dieters, however, in overlarge doses it can actually reduce testosterone production  Weider Prime Testosterone Supplements contain 167% of the recommended daily intake, which is fine, but it's important to make sure you don't take in too much from elsewhere.
DIM 50mg - DIM does depress estrogen leading to more free testosterone (the amount your body can actually use) which is a good thing. The problem is that some studies are suggesting that long term use of DIM, years not months, could suppress test production too.  And most men want a testosterone booster they can take for the long term, ruling DIM supplements out.
Ashwagandha Extract 675mg - Ashwagandha extract is great for any healthy testosterone support supplement as long as the user tolerates it well. It directly raises testosterone levels according to studies and has a bunch of tangential benefits to testosterone production. Such as stress reduction and better sleep quality, both of which in turn raise testosterone levels as well. This is a good choice for Weider Prime Testosterone Support.
Cordyceps Extract 390mg - Only shown to work in Rat Studies  cordyceps extract could in theory reduce the break down of testosterone within the body, but rat studies mostly don't translate to humans, so we can't say this is a good pick by Weider Prime Testosterone, we'd actually say it's quite a bad one when there's so many other proven ingredients available.
Bioperine 5mg - Bioperine is used to help your body absorb vitamins and nutrients, it's a good ingredient for any healthy testosterone support supplement, but it doesn't do anything do directly raise testosterone levels.
When comparing Nugenix vs Weider Prime Testosterone Support it dose depend on which of Nugenix T boosters we're actually looking at. For the most part Nugenix do win out although they're not much better, and certainly worse when you consider their price point. Nugenix win out on ingredients with some of their newer formulas, but Weider Prime do win out on price point. We wouldn't recommend either to be perfectly honest, although a lot of people seem to want to compare the two.
Read About Nugenix Total T
Weider Prime isn't terrible it just is an example of you get what you pay for. It's a relatively budget supplement that could easily be replaced by a multivitamin for most men. It doesn't stack up very well against the best testosterone boosters on the market even if it does contain some effective ingredients. It misses out on a host of more expensive proven test boosting supplements in an effort to keep the price down and appeal to a mass audience.
It's not going to be anywhere near the best option to help you build lean muscle mass or strip body fat. It does address some core (and common) deficiencies, so a lot of men will likely have positive results with Weider Prime by addressing these in the short term, but they could get a lot more from a better testosterone booster without the downsides of DIM.
1 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4658772/
2 - https://lpi.oregonstate.edu/mic/micronutrient-inadequacies/overview
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071499
4 - https://centertrt.org/blog/does-zinc-increase-testosterone.html
5 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3600969/
6 - https://pubmed.ncbi.nlm.nih.gov/26926141/
7 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824671/