While consumers have become more savvy about chemicals in food, clothing, and household products, it's often hard to distinguish speculation from science.

Some chemicals have known associations with cancer, autism, and reproductive issues, but others have been falsely linked to adverse health effects.

As with any chemical, the toxicity of a substance depends on the dose and how often a person is exposed.

The following chemicals are sometimes considered "toxic" or "unsafe," but don't actually seem to present a risk to human health.

Aspartame (artificial sweetener) was once thought to cause cancer, but scientific evidence suggests it's not a health risk.

Aspartame has gotten a bad rap over the years for the wrong reasons.

Most of the public concern surrounding the artificial sweetener has to do with rat studies that linked aspartame to blood-related cancers like leukemia and lymphomas. Both the US Food and Drug Administration (FDA) and European Food Safety Authority (EFSA) have discredited these findings, saying that aspartame is safe to consume.

The real issue with aspartame is that it's found in diet sodas, which aren't necessarily healthy. Research has shown that diet sodas can intensify your sugar cravings and may even lead to obesity.

Saccharin was once rumoured to lead to cancer, but there's little cause for concern.

Another rat study prompted a similar association between saccharin, a zero-calorie sweetener sold under the brand name Sweet'N Low, and cancer. In the 1980s, products with saccharin were required to carry a warning label saying that the sweetener was "determined to cause cancer in laboratory animals."

The study was later debunked after scientists discovered that the rats were prone to bladder cancer to begin with. Dozens of other studies have also found no association between saccharin and cancer.

In 2016, the National Toxicology Program removed saccharin from its list of cancer-causing ingredients.

Aluminium in your deodorant isn't going to give you breast cancer.

In the late 1990s, a viral email suggested that the aluminium in antiperspirants might be giving people breast cancer. The claim was backed up by preliminary research, but has since been proven false.

Both the European Commission's Scientific Committee on Consumer Safety and the American Cancer Society find no clear link between breast cancer and aluminium-containing antiperspirants.

Evidence suggests that our bodies only absorb small amounts of aluminium from antiperspirants – not enough to be considered dangerous.

Parabens can actually prevent harmful bacteria from forming in your make-up.

In 2004, a small study linked parabens – preservatives found in make-up and skin-care products – to breast cancer, but its methodology was flawed. The study looked for evidence of parabens in existing breast cancer tissue, but didn't identify where they came from or whether they caused or contributed to cancer.

There's also been some concern that parabens may disrupt hormone systems in a manner similar to estrogen, but the most common parabens are far weaker than the body's natural estrogen.

The FDA hasn't found any concrete evidence that parabens in cosmetics have an effect on human health. In fact, the chemicals help to prevent harmful bacteria from forming in your make-up, lotion, or sunscreen.

No, MSG won't give you headaches.

In 1968, a biomedical researcher claimed to experience numbness and heart palpitations after eating at Chinese restaurants. The cause of his symptoms, he said, was a food additive called MSG, or monosodium glutamate, which is also found in processed meats, chips, and canned vegetables.

In the 1990s, the FDA commissioned a review of the additive and found that MSG was safe to consume. The review also found that people who experienced headache, numbness, or drowsiness were likely to have eaten large amounts of MSG on an empty stomach.

But the stigma surrounding MSG has carried on: Around 42 percent of Americans still try to avoid consuming the ingredient.

Sulfates in shampoo are fine, if you're not already sensitive.

Conscious consumers might be inclined to purchased shampoo or body wash labelled "sulfate-free," but there's little reason to fear the sulfates. The ingredients are a surfactant – essentially a heavy-duty soap that makes it easier to trap oil and grease.

In the 1990s, sulfates were thought to be carcinogenic – a theory that isn't supported by scientific evidence. The only people who should be concerned for now are those with existing sensitivities, since sulfates can be both drying and irritating to the skin.

This article was originally published by Business Insider.

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