Molyslip - snake oil or used and good?

Some may have noticed I use my Jimny to tow a 750Kg caravan. It works hard to do this, very hard, so I keep an eye on servicing and how it's doing. 
I've noticed the rear axle is the weak point in the transmission, it gets very hot after a day's towing. 
Today's service has confirmed this, a little more debris on the drain Magnet than I would say is normal, certainly compared to the gearbox and transfer case. 

So wondering what can be done to help and Molyslip additive came up in conversation. 

Anyone got experience with this stuff in the axle? 

Snake oil or possible assistance for my poor axle? 

I have to admit I'm not a fan. In my opinion a good quality fully synthetic gear oil is probably a better bet.

You are still operating well within the standard capabilities of the vehicle. Stick to regular gear oil and observe the service schedule reccomendation of changing the oil every 24 moths/18,000 miles if towing. A small amount of metal on a diff drain plug is normal.

I change my transmission oil every 18k, have done  from the day I purchased it. This last 18k has seen some long (8hrs +) towing, i first notice the waxoyl on the axle case had "pimpled", it appears to be the result of heat, the axle simply gets hot over a long period with extra load. It doesn't happen if I run the vehicle for long periods without the caravan.
SO with interest I decided to change early,  this change was at 14k.
The gearbox / transfer oil looked new, minimal grey metal "fuzz" on the magnet for both. That's normally how the axle looks, but this time it had approx 3x the grey "fuzz" and  more concerning a few very small shiny slithers.

That's what's driving my question, the oils definitely working harder in the axle when you tow for long periods of time.

I think I'll change the axle oil more frequently, possibly every year if I tow. The gearbox / transfer case looks fine at the 18k interval.

THanks for the feedback, tend to agree and be cynical with additives, but Moly (for gearbox/axle) gets good reviews on Amazon.
 

At my work we make gearboxes for ships. Not the same i know as we are mostly in the 2000kW to 6000kW but still some similarities.
The point where the gear wheels touch make the most heat. The teeth on one gear is supposed to roll on a film of oil on the other gear. If they rub it is called scuffing and this produce heat and breaks down the oil and wear on the surface.
The point of contact can reach high temperatures and will degradate the oil. How well the oil can withstand this is important.
We do not approve any additives or mixing of oils. Well known brands and good specs is all there is to it. And regular test intervals and oil change.

Sound advice from all - thanks.