1. It Lowers Stress Hormones
The most profound benefit, according to Dr. Berg, is stress relief. “If you feel nervous, this is the best herb to take,” he says. Ashwagandha is what’s known as an adaptogen—a natural substance that helps your body cope with stress by balancing the nervous system and hormone levels.
“Ashwagandha has been known to significantly lower cortisol,” Dr. Berg explains. Cortisol is the body’s primary stress hormone, and chronically high levels can lead to anxiety, poor sleep, weight gain, and even insulin resistance.
2. It Can Help With Sleep and Brain Fog
Stress-induced insomnia is another area where ashwagandha shines. “Because the lowering of cortisol is occurring, you’re going to feel calmer, you’re going to have less anxiety, better brain function, and less brain fog,” Dr. Berg notes.
For those who toss and turn due to stress or anxiety, taking ashwagandha could be a natural solution to help restore healthy sleep cycles.
3. It May Boost Metabolism and Weight Loss
Too much cortisol doesn’t just affect mood—it also messes with your metabolism. “Cortisol can cause insulin resistance,” Dr. Berg says, which can lead to conditions like fatty liver, elevated blood sugar, and stubborn weight gain.
By lowering cortisol, ashwagandha may support weight loss and improve your body’s sensitivity to insulin, especially if you're struggling with stress-related weight gain.
4. It Supports Hormonal and Immune Health
Ashwagandha also plays a role in hormone regulation—particularly male hormones. “It’s been known to improve male hormones, specifically testosterone,” says Dr. Berg. This can lead to improved sex drive, sperm count, and even sperm mobility.
It may also support thyroid health—especially in cases of underactive thyroid (hypothyroidism)—and can help regulate immune function by balancing stress hormones.
5. It Helps With Pain, Inflammation, and Endurance
This herb doesn’t just work on the inside. “Ashwagandha is good for pain, helping people with low back pain, improving muscle spasm, and it’s good for fluid retention,” Dr. Berg explains. It’s also known to improve endurance and stamina during exercise thanks to its anti-inflammatory properties.
When to Avoid Ashwagandha
While generally safe, Dr. Berg cautions that ashwagandha isn’t for everyone. Here are some situations where it should be avoided:
If you’re sensitive to nightshades “If you have a sensitivity to the nightshades, you probably don’t want to take it,” he says.If you have excess iron or hemochromatosis “Ashwagandha is high in iron, so if you have a genetic problem where you accumulate iron, it’s not good for you.”If you have hyperthyroidism While ashwagandha can stimulate the thyroid in helpful ways for underactive thyroid, those with an overactive thyroid (such as Graves’ disease) should steer clear.If you’re pregnant Though it’s been used traditionally in pregnancy in India, Dr. Berg warns: “There are no safety studies that look at pregnant women taking this herb. So it’s best to avoid it during pregnancy.”
He also notes that ashwagandha may interfere with thyroid and barbiturate medications, so always check with a healthcare provider before adding it to your routine.
How Much Should You Take?
Based on randomized clinical trials, Dr. Berg recommends:
250–500 mg of ashwagandha capsules, twice a dayOr 40–80 drops of a tincture (2–4 mL), three times per day
“I personally don’t like tinctures in alcohol,” he says, “so I take capsules. But many people like tinctures, and they seem to work just fine.”
The Bottom Line
Ashwagandha might smell a little funky—its name literally refers to the scent of horse urine—but it’s earned its place in the spotlight. From stress relief to hormonal balance and better sleep, this adaptogen offers a wide array of benefits. Just make sure you’re taking it safely—and not if you fall into one of the “avoid” categories.