Ashwagandha's Effects on Muscle Growth

Find out more about ashwagandha's impact on muscle growth beyond stress relief—uncover its impact on cortisol and testosterone levels, and how it can enhance your health and fitness journey for improved strength.

Inside Tracker icon
By Staff Writer
Lucia Gcingca
Edited by Lucia Gcingca

Published January 20, 2024.

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What benefits does ashwagandha offer for muscle growth? When we think of supplements for strength and muscle building, modern options like creatine, whey protein, or BCAAs come to mind. But evidence links ashwagandha supplementation to notable muscle mass and strength boosts, showing us it can be handy alongside a resistance training program. [1]

This herbal supplement with ancient roots deserves equal attention from today's performance and strength-building communities.

What is ashwagandha?

Ashwagandha, hailing from the roots of the Indian Withania somnifera plant, is an herbal supplement that's been used in naturopathic medicine for centuries. As an adaptogen, it helps our bodies adapt to certain situations.

It's best known for reducing stress and anxiety and restoring "the strength of a horse,” as its loose translation implies. While these effects are well-established, lesser-known effects like ashwagandha's impact on muscle growth, glucose, testosterone, and strength levels make it an excellent addition to your gym bag.

» Find out how you can improve your athletic performance with a blood test

What is cortisol's role in stress management?

The body is constantly reacting to stressors in the world, both physical (like from exercise) and emotional (like from deadlines at work). Regardless of its source, the body deploys the hormone cortisol to respond to stress. This is why cortisol has earned itself the nickname "the stress hormone."

Cortisol is produced in the adrenal glands. It regulates your energy, metabolism, and immune function during stressful moments. Cortisol's effects have deep evolutionary roots. When humans lived in caves, if they stumbled upon a threat (like a predator), the body would immediately produce cortisol to initiate the fight or flight response.

Cortisol re-wires how the body uses energy by breaking down muscle for energy, increasing blood sugar, and halting digestion—literally preparing their bodies to fight for their lives.

Most of us will never be chased by predators, but we do have 21st-century physical and emotional stressors that elicit the same responses in our bodies. And cortisol's effects are still useful, despite the differences in livelihoods from our evolutionary ancestors.

Cortisol's effects help us stay wired when working against the clock and be mentally sharp in high-stress situations. But these benefits come with a price.

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Negative effects of high cortisol levels

High cortisol encourages muscle breakdown, fat storage, and impaired recovery.

Cortisol is considered a catabolic hormone, so it increases the energy available to our bodies in times of need by stimulating the breakdown of muscle. However, this can negate some of our hard work and training in the gym if left unchecked.

High cortisol levels will slow digestion and, in turn, stimulate the storage of fats. High cortisol can also:

  • Reduce testosterone: High cortisol levels can slow down testosterone production. When compounded with cortisol's impact on muscle breakdown, this can be bad for gains as testosterone is an important player in muscle repair, growth, and recovery.
  • Prevent deep sleep: Cortisol levels naturally rise in the morning to stimulate a wakeful state. Chronically elevated cortisol can disrupt your natural sleep/wake cycle, ultimately preventing the body from entering restorative deep sleep and contributing to fatigue.
  • Suppress the immune system: High cortisol levels will slow down immune function, making you more susceptible to getting sick and preventing recovery after hard workouts.

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Ashwagandha's impact on cortisol and muscle growth

Scientists haven’t yet nailed down the exact mechanism of action for ashwagandha's impact on cortisol. Still, the practical evidence of its usefulness is from a large and robust body of scientific evidence.

As mentioned, elevated cortisol is terrible for muscle building, so keeping cortisol levels low is in our best interest—exactly where ashwagandha shines. Recent studies have shown that this herb's effects on strength and power aren't just cortisol-dependent as it:

  • Decreases serum cortisol by up to 27% [2]
  • Contributed to a 17% increase in total testosterone [3]
  • Increases raw strength, muscle size, and VO2 max [1, 4, 5]
  • Lowers LDL (bad) cholesterol, blood glucose, triglycerides and hs-CRP [6]
  • Increase HDL (good) cholesterol and DHEAS [6]

Ashwagandha can’t remove the stresses from our lives, but it can help us cope with them. Keeping an eye on your cortisol levels and having an arsenal of solutions that work with your lifestyle will help you stay strong.

» Bulking up? Check out our nutrition checklist for muscle building and recovery

What to look out for before you try ashwagandha

Before you add ashwagandha to your supplement regimen, there are some circumstances that you need to consider:

  • Taking ashwagandha while pregnant There haven't yet been studies on the effects of ashwagandha in expecting mothers, so if you’re pregnant, best hold off on adding this to your supplement plan.
  • Allergies The W. somnifera plant is a close relative to the nightshade family, those who are allergic to nightshades should avoid ashwagandha at all costs.

Ancient benefits with a modern twist

Keep in mind that before diving into supplements like ashwagandha for muscle growth or stress relief, chat with your doctor and be sure to check your bloodwork—this can help you figure out the best supplements and doses for you.

Interested in determining effective ways to meet your health goals? InsideTracker brings personalization to your wellness journey, guiding your nutrition, exercise, and lifestyle choices based on your unique blood biomarkers, genetics, and physiological data from wearable devices.