"Ordered it 5 times now and they have yet to deliver it on time. Order and expect it to be late, so order/reorder early. Like it enough to keep reordering but removing a star because they can deliver it when they say."

"FINAL UPDATE, 1/16/2016: I've decided to cut way way back on this. Might even quit. I've used it continuously for over a year. For the last 6 months I have taken 1 g per day, in 4 divided doses. I'm not sure that it is benefiting me anymore, to the extent that it actually did. Regarding my night vision improving, I am not an outdoors person, and I had not noticed how much brighter the sky is at night when the moon is out! On the Vince Giuliano & Jim Watson Aging Sciences blog, Jim Watson suggests that certain homeostatic mechanisms tend to cause NAD+ increases to be transient. I have come over to that opinion. What finally made me decide to quit was the reappearance of a peculiar visual disturbance associated with modest LSD use when I was 19. For 40 years I have often gotten these bright sparkles or lights in my visual field when I turned my head suddenly or coughed with unusual force. The visual characteristics of these sparkles had been absolutely unchanging -- always of exactly the same brightness, size, thickness of the trail, etc. Then after I started taking nicotinamide riboside they suddenly dimmed dramatically, and then flat-out disappeared. I figured that was a good sign. But it was discouraging even to see it come back one-time. This stuff is too expensive. The hearing improvement was very real, I believe. I noticed around July of last year that I could hear a mosquito's buzzing, and I think that people my age (64) normally can't hear that high-frequency sound. Never did get my ears checked, though.
update, 3/4/2015: here is an update after 4 or 5 months of continuous use:
(1) something I just noticed a week ago: a number of people on the web have said that their night vision improved dramatically. I didn't notice any such effect at first and stopped thinking about its possibility. For the last month or so I've been wondering at the brilliance of the night sky as seen from my front windows. I get home late from work, around 1 or 2 AM, and I don't turn on the lights so as not to disturb my wife. So at this time I tend to be walking around in a dark house, and I've been almost shocked at how light the night sky is as seen through my windows. I live in a large metropolitan area, and I've been explaining the brilliance as owing to some sudden increase in urban illumination. But it suddenly struck me that my night vision for some reason had greatly improved. After observing my night vision in my house in various situations for a week, I have concluded that my night vision has greatly improved.
(2) I also just realized that the bad habit I complain about below that has basically prevented me from getting any writing done for the past couple of years at home has just dwindled and dwindled and dwindled and finally -- poof! -- has disappeared. I attribute it to overall and progressive but imperceptible improvement of brain function. This blows my mind (I'm glad not literally).
(3) the male problem I also complain about below has continued to progressively improve to the point that function has been, I would guess, about 85% restored. This also blows my mind. Note: here there is a possibility that my loss of a good deal of belly fat on a low-carb induction diet lately has significantly contributed. Losing belly fat is supposed to improve blood vessel function.
(4) I take 4 capsules daily, at (more or less) 6 AM, noon, 6 PM, and midnight. I take them with food about half the time. If I take more than 4 per day, a strange and enervating fatigue sets in.
(5) my hearing still seems to be marvellously improved, but I don't pay much attention to it anymore.

HERE IS THE EARLIER REVIEW:
I think that the nicotinamide riboside that is the only active ingredient in this product is an extremely important advance in anti-aging, though I'm skeptical of many of the ad-copy-like or placebo-effect-like comments. I'm reasonably confident that HPN is giving us an unadulterated product. HPN is definitely giving us the best deal in terms of how much you get for what you pay for. (I've done the math.) I think HPN is hyping the effects of nicotinamide riboside a bit too much. People contemplating a purchase should bear in mind that David Sinclair and Leonard Guarente say that you have to take 500 mg to 1000 mg a day to benefit from it (I would give you the link but Amazon doesn't like links). At 500 mg a day you would run through about two bottles a month. I personally think it is worth it.

Here is my experience based on a total of about two months use. I'm a 62-year-old male. All of the effects about to be noted occurred within a month of starting to take the product. I've noticed these effects: 1) startling indications of sudden improvement in my hearing (I have no hearing impairment), 2) a sudden striking moment where I was able to lay aside a home-computer addiction of sorts and get on with work of real importance with a focus that was extraordinary for me (been struggling with this issue for months, and not once had I been able to get past it), and 3) a sudden and substantial improvement in a certain male issue common enough in and hard on geezers like myself.

The seeming unrelated character of the effects tells me that systemic improvements are taking place. Wunderbar!

Effect #2 prompted me to suddenly increase my dose from 375 mg (3 pills) a day to six and more. Onward and upward! At this time a general and quite serious fatigue settled on me that was very vexing. I never did notice my energy level increase, but it has always been high. Today I just got back to 375 mg a day, where I intend to stay. The fatigue is mostly dissipated, and I believe will dissipate completely in the next day or two.

I sure want to know where the fatigue came from. It is not necessarily a bad sign. One result of the increasing NAD+ deficiency that occurs with aging is that some cells -- maybe that of whole subsystems -- switch away from a mitochondrial genesis of energy to a much more harmful and pro-aging means of generating energy. Maybe the fatigue comes from a partial or incomplete switching-back to the earlier way of generating energy. Maybe with more time the fatigue would go away and I could take a higher dose.

Please note that I am a verified purchaser (of four bottles so far). I intend to keep buying this particular product."

"Nothing to say yet, but I take a lot of supplements so hard to tell."