Since the Fen-Phen fiasco of the 1990s (in case you forgot, that’s where weight loss turned into life loss as a result of the deadly drug combination of fenfluramine/phentermine), weight loss supplements have been battling an uphill battle for legitimacy. But that hasn’t stopped us from scarfing them down to make sure those chocolate chip muffins don’t wind up as our own muffin tops.

Though each supplement and every individual is different there are four important questions everyone should ask themselves before deciding to buy and swallow a weight loss supplement. Like Fen-Phen taught us, actual weight loss is only one part of what you should be thinking about.

1. Is the weight loss supplement you are taking banned?

Unfortunately, the Food and Drug Administration (FDA) doesn’t regulate any dietary supplements, including for weight loss. That means that marketplace is full of both legitimate and dubious products, with little more than your own smarts to distinguish which is which. That means you have to do your homework when thinking about a particular product.

Even if the FDA doesn’t regulate supplements like it does other drugs, it does monitor its safety once it is on the market and may issue recalls or bans. Check its website to see if what you are considering ingesting is part of the more than 100 weight loss supplements that the FDA has found to contain hidden and often dangerous drugs or ingredients.

The most important thing to do, however, is to read the label carefully and talk it over with a pharmacist or your doctor.

2. Do you have health conditions which are compromised by weight loss supplements?

Before you take any kind of supplement, especially for weight loss, consider your current state of health and particular health conditions. Supplements may contain seemingly harmless ingredients, which could provide dangerous with certain preexisting conditions.

Take one of the more popular recent weight loss supplements, garcinia cambogia (which comes from the tamarind fruit). It has some very positive fat-blocking and appetite suppressing qualities. What you should know is that the same hydroxycitric acid that is credited with producing those characteristics is also dangerous for women who are pregnant or breastfeeding and can increase the negative effects of Alzheimer’s disease or dementia.

You also have to take into account any other medications or supplements you may be taking as certain combinations can be dangerous and even lethal. That information is usually beyond what the layperson would know, so it is important to talk it over with your doctor or pharmacist.

3. Can natural weight loss supplements be dangerous?

Although it always makes sense to consider weight loss supplements with all natural ingredients, that doesn’t necessarily mean you are out of the woods.  Take, for example, ephedrine, which comes from the Chinese plant ma huang and which was the main ingredient of a number of dietary supplements in the last decade.  Until that is, the FDA banned it in 2004 as a result of accumulating evidence of adverse effect and several ephedra-related deaths. The lesson: Mother Nature can be as lethal as any laboratory.

4. Are your expectations reasonable?

By now you should know that a magical pill or elixir that promises to burn all your fat without you having to get off the couch is not realistic. But that doesn’t stop users from creating unrealistic expectations. And when those are not met, often they up the ante and start taking more of a weight loss supplement than is recommended or for an extended period of time to sometimes dangerous levels.

That’s why you have to keep your expectations within reason. If a weight loss supplement is not working like you hoped it would within the prescribed dosages, just ingesting more for longer isn’t going to do any better and it may very well do harm.