Every day, the body’s metabolism works diligently to convert food to energy. Some people need a lot of nourishment to keep their internal engines going, while others have a very slow metabolism, which requires consuming fewer calories to maintain a healthy weight. A slow metabolism can be a sign of a body running very efficiently, but it can also signal an underlying condition causing fatigue and diminished mental clarity. Not only can the body’s metabolic rate be altered by weight loss and frequent dieting, but it can also shift with age and medications. A sluggish thyroid could also be responsible.

“As naturopath doctors, we are always really intrigued at finding the cause as to why someone’s metabolism may not be as robust as it should be,” says Micah Allen, N.D., owner of Essential Natural Health in Richmond, Virginia. Allen, also a licensed acupuncturist, says thyroid dysfunction, autoimmune issues, blood sugar levels and metabolic syndrome—a precursor to diabetes—can all influence metabolism.

Eating a balanced diet (with lots of protein), exercising regularly, hydrating properly and getting enough sleep are all key to maintaining a healthy metabolism, but here are some natural metabolism boosters for an extra fuel-burning nudge, if needed.

Coenzyme Q10

Our bodies naturally produce coenzyme Q10 (or CoQ10), which creates energy on a cellular level, speeds up metabolism, regulates lipids, and fends off oxidative stress and fatigue. It’s particularly abundant in muscles, including the heart. When we are deficient, our metabolism can slow down, and we may feel sluggish. Also, studies show that when statin drugs are taken to lower bad cholesterol, the drugs also block production of CoQ10. It’s something to think about, considering that 28 percent of Americans over age 40 are on statin medications.

Doctors usually recommend CoQ10 in the form of ubiquinol because it is easier to absorb. A 100 mg dose is suggested for maintenance; consult with your doctor to confirm the best dose.

Vitamin C

Yes, the trusty cold fighter that is great for immune-system support can also accelerate your metabolism by fighting off oxidative stress. This can particularly help older people, as a study conducted at the University of Colorado Boulder discovered. Researchers noted that the body produces ample antioxidants in younger people, but with age this production diminishes, causing more oxidative stress and damage to cells, which in turn can reduce resting metabolism, especially in older adults, researchers believe. The study found that when adults ages 60 to 74 received vitamin C injections, their resting metabolism increased on average by almost 100 calories per day.

Vitamin C has also been shown to boost fat burning and regulate glucose metabolism and blood sugar levels by helping to shuttle glucose into cells to be used as fuel. This glucose regulation is important for diabetics, for whom too much glucose in the bloodstream can damage organs and blood vessels. The body needs vitamin C to produce sufficient amounts of L-carnitine, an amino acid that has also been shown to enhance metabolism. A recommended dose is 100 to 200 mg each day.

Alpha-Lipoic Acid (ALA)

This powerful antioxidant, which is rich in anthocyanins—the dark pigments found in fruits such as raspberries or blueberries—not only fights off cell-damaging free radicals, but has also been shown to increase weight loss and reduce blood sugar levels. It encourages the production of the protein hormone adiponectin, which regulates fat cells and can improve metabolism while influencing the rate at which your body breaks down fat.

Although more research is needed to understand long-term benefits of ALA on weight management, studies have shown it to promote weight loss compared with placebos. A recent study conducted in Spain and published in the journal Obesity indicated that ALA may raise metabolism, promote the burning of fat as energy and encourage reduced food intake. The body can produce ALA naturally—it does so inside the mitochondria, the cell hub where it helps enzymes transform nutrients into energy. But the body is capable of producing only small amounts. Likewise, it’s hard to get a larger dose through food. This is why supplementation—300 mg each day—is recommended.

Green Tea

Frequently lauded for its health benefits, green tea contains catechins, natural antioxidants that thwart cell damage. One type of catechin in particular, epigallocatechin gallate (EGCG), is known to increase metabolism. It does so in part by inhibiting the enzyme that breaks down the fat-burning hormone norepinephrine. When this happens, more norepinephrine can be produced, resulting in greater fat breakdown. Add this to green tea’s caffeine content, which is lower than coffee but still significant, and green tea is at the ready to jump-start metabolism.

In a 2017 research review, it was found that daily consumption of green tea with doses of EGCG between 100 and 460 mg can reduce body fat and body weight, especially when taken for periods of 12 weeks or longer. In addition, daily use of caffeine in doses between 80 and 300 mg has been shown to stimulate EGCG’s metabolism-boosting effects. When a lesser amount of caffeine was taken, the results were not as pronounced.

Chile Peppers

Certain foods are known to be metabolism boosters. Chile peppers or hot peppers are a member of the capsicum family and contain both capsinoids, including dihydrocapsiate and capsaicin, the oily compound found in the membrane surrounding the seeds. The latter is what gives peppers their heat or spicy flavor. Research has shown dihydrocapsiate and capsaicin to increase metabolic rates modestly. Capsaicin also has been studied for its ability to use heat to spur metabolism and burn fat. In this capacity, the online journal Open Heart outlined that capsaicin has been shown to modestly enhance energy expenditure, while boosting fat oxidation and diminishing appetite. Although peppers do give your metabolism a lift, supplementation is necessary to maintain the increase, because you would have to eat peppers daily to sustain these effects.