I take VitaPulse dietary supplements from the Princeton Nutrients. Once the bottle is open for a week or so, the contents begin to smell. Should I be concerned?

Answer:

We have not yet tested VitaPulse, but the label states that each capsule contains NAC (250 mg), as well as CoQ10 (100 mg) and PQQ (10 mg). The odor you smell is likely from the sulfur that is part of NAC (N-acetyl-cysteine) — this is normal. This is discussed in the "What to Consider When Buying" section of our NAC Supplements Review.

If you want these ingredients, be aware that you can purchase them as individual supplements at a much lower cost than in VitaPulse, which currently sells for $235 for 6 bottles (containing 30 capsules each), i.e., $1.30 per capsule. In our NAC Supplements Review, capsules with twice as much NAC as in VitaPulse sell for as little as 10 to 20 cents. In our CoQ10 Supplements Review, capsules with 100 mg of CoQ10 sell for as little as 9 cents — and these are products which we have tested and approved for their quality. We have not tested PQQ (but have written about it). It is a relatively expensive ingredient, but you can get 10 mg capsules of PQQ from reputable brands for less than 40 cents. In short, you should be able to cut your cost by at least half by purchasing the individual supplements — and you will limit the odor issue to just the NAC product.  

Also see answers to these related questions:

If I buy NAC as a loose powder in a large bag, as opposed to in tablet form, will it spoil? I've heard it can spoil or degrade into a harmful by-product. >>

Can taking N-acetylcysteine (NAC) supplements reduce my risk of liver damage from acetaminophen? >>

Is it true that NAC can help clear nasal passages? >>

What is the difference between cysteine and cystine? >>