Sneeze in a room full of family, friends, or coworkers, and you’re bound to receive buckets of unsolicited cold and flu remedies people swear by—assuming they haven’t put on their gas masks and run away.

Given the ineffectiveness of this year’s flu vaccine (although it’s still worth getting—here’s why) and that forever-elusive “cure for the common cold,” many of us have found ourselves turning to some combination of Grandma’s home remedies, health food stores, and integrative health specialists for help. But even as we’re meticulously dosing ourselves with vitamins and herbs, we’ll be reading the latest headlines about scientific studies indicating it’s all snake oil.

Who should we believe? Is there a Big Pharma conspiracy out there, or are alternative medicines just another product in a for-profit system? If I think my favorite homeopathic cold medicine makes me feel better… can’t I just trust my anecdotal experience?

“I don’t think mainstream medicine is looking to be proactive,” says Deepa Verma, M.D., AIHM, an integrative health physician, says of the mainstream approach to cold and flu viruses. “They’re reactive—they just wait for things to happen and then treat it. That’s what I was taught in med school.”

Natasha Bhuyan, M.D., the district medical director of One Medical in Phoenix, Arizona, explains that unfortunately, money often plays a role in whether traditional doctors recommend alternative medicine.

“Doctors can’t often endorse these treatments as there is a lack of trials and research on them,” she says. “This is simply because funding a research trial is super expensive. It would be amazing if there were a lot more funding support for alternative treatments.”

In many instances, alternative treatments may be as effective—perhaps more effective—than mainstream approaches. However, these treatments generally don’t receive the same kind of funding for high-quality clinical trials, so we can’t know for sure about their efficacy.

Where Science and Integrative Health Agree

Verma bases her practice on her own analysis of published research—and most of what she prescribes for her patients revolves around boosting their immune systems.

One of the supplements she recommends for immune system health is vitamin D (yeah, you may have thought we were going to say C—we’ll get to that surprisingly controversial vitamin later).

“I live in Florida, and the number of people who are vitamin D deficient here is staggering—so you can imagine what it’s like in people in the Northeast or Midwest,” she says. “Studies have shown that vitamin D is very powerful in boosting immunity and preventing cancer, and also helping with a host of other things like heart disease, obesity, and diabetes.”

Because the FDA doesn’t regulate what goes into supplements, Verma said the best bet for patients is to get pharmaceutical-grade supplies straight from an integrative health specialist, naturopathic doctor, or other medical professional. She often administers her supplements via IV, so the active ingredients bypass the digestive system and enter the bloodstream in purer forms.

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Does Vitamin C Really Help Prevent a Cold?

Verma also relies on established knowledge about how our immune systems sometimes fail us. The thymus gland, for instance, is where the body produces disease-fighting T-cells, but it naturally atrophies with age. An age-old remedy for treating the gland involves consuming the thymus glands of calves, and some current studies support this practice in the form of a supplement, which is derived from the same source but thankfully doesn’t involve actually snacking on a literal thymus gland.

The liver produces the antioxidant glutathione (GHS), which helps us fight infections but depletes naturally as we age. Reduced levels of GHS are associated with upper respiratory tract issues. In hospitals, when patients have overdosed on Tylenol, they’re given N-acetyl-cysteine (NAC), a glutathione precursor, to replenish their GHS. Studies have shown that NAC has also helped HIV patients and postmenopausal women improve their immune function, and some studies have shown it to be effective in fighting influenza. That’s why Verma often administers glutathione infusions after an IV.

Elderberry, aka sambucus nigra, also appears promising. This plant (when processed to eliminate naturally occurring cyanide) has antiviral properties and has been shown in multiple trials to be moderately effective in preventing people from catching the flu and colds, and failing that, in shortening their length.

Bhuyan is optimistic about Pelargonium sidoides, an ingredient in Umcka, a common natural cold medication. “There have been two fairly good randomized studies that show this can reduce the severity of symptoms of the common cold and acute bronchitis,” she says.

“This is an herb that has been widely used in South Africa and Europe. Early lab studies show it has antibacterial and antiviral properties, in addition to giving your immune system a boost. However, in medicine, we are always seeking more evidence (i.e., multiple, super-strong trials with thousands of patients). But I still recommend this, as it’s safe to use and has good early data.”

Remedies Science Isn’t So Sure About

Headlines about the efficacy of vitamin C fluctuate about as much as those for red wine, eggs, and coffee. The latest verdict from the National Institutes of Health on vitamin C is that it’s an important antioxidant, and adults should consume about 75-90 mg a day, preferably from food. But they say it’s not the miracle cure for colds and flu.

“There are fascinating studies on vitamin C,” Bhuyan says. “A large analysis of 29 trials showed a small reduction in the duration of cold symptoms, but only in adults taking regular vitamin C (200 mg a day). It didn’t really show a benefit for people who start taking it when they feel a cold coming on.”

The results have been similarly disappointing for echinacea and colds. But when you go to the research on the immune system, both vitamin C and echinacea seem to do some good work. That’s the research Verma pays attention to when she formulates her IV fluids in a combination called Myers’ Cocktail, after a doctor who developed the method in the 1960s. When someone comes into her office feeling cold or flu symptoms, she typically uses about 25 grams of vitamin C, plus trace minerals, B vitamins, and glutathione.

“I take all those articles and I just compare them,” she tells Greatist of what she does if the latest studies cast some inconclusive doubt on certain supplements. “I look at how the research was done. If they’re inconclusive, I just do more research. If I can pull more articles that are saying it’s more beneficial than not, then to me, that works. When I’m doing these treatments with my patients, I do check in on them a few days later, or they send me a text or email and tell me they’re better or didn’t come down with the flu.”

After administering her Myers’ IV, Verma sends her patients home with echinacea, thymus extract, and two more ingredients with ambiguous science behind them: medicinal mushrooms and astragalus root.

The National Center for Complementary and Integrative Health (NCCIH) says the research on Chinese herbal remedy astragalus is sparse and poorly conducted—which doesn’t mean that astralagus isn’t a good supplement, it just means we don’t know yet. Studies on various medicinal mushrooms seem quite positive so far—particularly in terms of its antiviral properties in the face of influenza—but very few have been conducted. As Bhuyan notes, it seems there just hasn’t been enough money used to look into these naturally available ingredients.

What No One Is Recommending: Homeopathic Medicines

Coldcalm and Oscillococcinum are two brand-name homeopathic medicines widely available in stores. I load up on them every time I feel like I’m getting sick, and I feel like they keep me healthy or shorten my illnesses. But there’s a huge chance that’s all in my head.

A review of six studies of Oscillococcinum, which is derived from duck heart and liver but diluted down to one percent, found that the only evidence that this treatment shortens the flu came from a possibly biased study. The idea behind homeopathy—that an almost undetectable amount of a thing that’s similar to what is making you sick will activate your body to get well—has been met with a lot of criticism, and manufacturer Boiron has been sued for its claims. At the same time, Bhuyan doesn’t tell people not to use it.

“It’s up to the patient if they want to use this product and spend the money,” she says. The benefit of this medicine might be (read: probably is) a placebo effect, which is another way of saying that our minds can make us feel better too—at least a little bit.

“There is definitely validity to the placebo effect,” Verma says. “When you think of something, it can manifest. That’s why we encourage people to do meditation and think positive thoughts. When you have positive thoughts, you’re releasing chemicals into your body that boost your immunity. That mental aspect goes hand-in-hand with the physical aspect. But your thoughts only go so far.”

How Can We Make These Decisions?

Read up! Most of this research is available online, after all.

“Patients should feel empowered to read medical studies themselves and discuss them with their doctors,” Bhuyan says. “When reading a medical study, here a few questions to ask yourself: Who funded this study and could there be some bias? Is the study well-designed, with enough patients and a control group? Were the end results actually meaningful to my life?”

Sure, these make for dry reading on a sick day—but you can always balance it out with a few hours of streaming Riverdale.

Sabrina Rojas Weiss lives in Brooklyn, surrounded by her fellow freelance writers and competitive stroller-pushers. Follow her on Twitter @shalapitcher.